soil and water: research by the british army's committee on mud crossing performance of tracked...

Geological Society, London, Special Publications

doi: 10.1144/SP362.9p161-186.

2012, v.362;Geological Society, London, Special Publications David A. Greenwood Armoured Fighting Vehicles in World War IICommittee on Mud Crossing Performance of Tracked Soil and water: research by the British Army's

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Soil and water: research by the British Army’s Committee

on Mud Crossing Performance of Tracked Armoured Fighting

Vehicles in World War II

DAVID A. GREENWOOD

The Kirkaldy Society, 7 Vernon Crescent, Barnet, Hertfordshire, EN4 8QG, UK

(e-mail: [email protected])

Abstract: Problems experienced by armoured fighting vehicles (‘tanks’) crossing soft groundbecame apparent during World War I. These were avoided early in World War II by the use of‘going’ maps in North Africa from 1940 to 1943, but when operations moved to NW Europe itwas realized that there would be the additional problem of changes in ground conditions due tovariations in soil moisture according to the weather. This led to an investigation into factors con-trolling the movement of tracked vehicles over water-softened ground, beginning in July 1944 withthe establishment of the ‘Mud Committee’, tasked to consider problems in light of recent develop-ments in the (then) new science of soil mechanics. Contemporary ideas, as applied to building androad construction, were found to be inapplicable, and attention was therefore focused on empiricaltrials. The Committee faced the constant problem of balancing the requirement for short-termresults with the need for long-term research. As a result, it failed to meet many of its objectivesby the end of hostilities, but its work did provide a sound basis for the development of a methodof classifying soils for military purposes and for future work on track design.

In 1944, the British Ministry of Supply set up a22-man committee entitled ‘Committee on MudCrossing Performance of Tracked Armoured Fight-ing Vehicles (AFVs)’. From the outset, this bodywas referred to as the ‘Mud Committee’, bothwithin its own reports and by others, and thatnomenclature will be used throughout this paper.The records of the Committee’s activities are filedunder its full title at the British National Archives,with the abbreviation ‘CMCP’. The Archives hold96 reports out of a possible total of 111 in Depart-ment Section WO 194, all prefixed ‘MC’ followedby a number from 1 to 111 (see Appendix 1).

There were two inherent weaknesses in the struc-ture of the Committee. First, it did not have its ownSecretariat. Second, it was expected to draw onfunding already allocated to its constituent bodies.Consequently, the Committee’s reports usually ori-ginated within these different bodies and there areconsiderable differences in format and in the exactname given to the Committee in report titles, withvariations such as ‘Chobham Committee’, ‘TrackLaying’ and ‘Bog Crossing’. The Committee hadits first meeting on 18 July 1944 and continued itswork until 1946. The work of the Committee wasrelatively self-contained, and its demise in 1946provides a natural cut-off point. As a result, sub-sequent postwar developments, often pursued byenthusiastic individuals through a variety of organ-izations, have not been considered in detail in thepresent paper. For a brief resume of such work,see Ogorkiewicz (2002, pp. 143–144).

Background

Tanks were first used on the battlefield on 15September 1916 when they were employed by theBritish Army during World War I in the Sommecampaign at the Battle of Flers 2 Courcelette(Fletcher 2004). These early machines, with theircharacteristic lozenge shape, had been specificallydesigned to cross enemy trenches up to 2.7 m(9 ft) wide and to be able to climb out of shellcraters or natural depressions. They had no suspen-sion and were fitted with a continuous ‘girder’ trackthat was supported directly by the body of the tank.The lozenge shape ensured that a large proportionof the track was in contact with the ground at anyone time. Steering was achieved by a subsidiarypair of wheels at the rear of the vehicle. Little orno thought seems to have been given to their overallground-crossing ability, and speed was restricted tono more than walking pace.

Problems in the use of these machines becameapparent from the outset, particularly with regardto bogging in soft ground and mechanical reliability.This is illustrated by the statistics from the first dayof the battle, with Fletcher (2004) noting that of the49 tanks available only 32 reached the start line. Ofthese, five were lost in shell holes or trenches, ninebroke down and nine more failed to keep up withthe advance. Only the remaining nine reachedenemy lines, despite the attack taking place overfavourable ground on Cretaceous Chalk. Conditionselsewhere along the British sector of the Western

From: Rose, E. P. F. & Mather, J. D. (eds) Military Aspects of Hydrogeology.Geological Society, London, Special Publications, 362, 161–186, DOI: 10.1144/SP362.9# The Geological Society of London 2012. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics

at Indiana University Libraries on July 1, 2014http://sp.lyellcollection.org/Downloaded from


Front were far less conducive to tank warfare. Theseranged from the residual clay-with-flints andQuaternary loess/loam (limons des plateaux), over-lying much of the higher ground of the Chalk in thesouth, to the Palaeogene clays and wet sands to thenorth in Flanders (Doyle 1998). As both Rose &Rosenbaum (1993) and Doyle (2012) have shown,there was a large amount of detailed geologicalinformation available at a local level, and this wasused extensively in the siting of ‘dugouts’ andother excavations, including maps that were colour-coded to show groundwater conditions (Rosenbaum1989; Rosenbaum & Rose 1992). ‘Tank maps’ wereprepared by the Tank Department itself, ‘certainpoints only being referred to the geologists’ (Anon.1922, p. 45), and ‘Tanks’ were furnished with themaps prepared by the British military geologistsshowing conditions for dugouts and some detailsof soils and subsoils in areas invaded by theenemy. Geological considerations were perceivedto be ‘frequently of considerable importance fromthe point of view of the possibility of movingtanks over the ground’, but the British had too fewmilitary geologists to attempt detailed work ontank maps.

In fact, the British General Staff in World War Ioften ignored information available on local con-ditions in favour of more strategic considerations,especially with regard to ground that had to be‘held’ for political considerations. A proposal wasmade by a Tank Corps Staff Officer, Major (laterMajor General) J.F.C. Fuller, to draw up what hecalled ‘swamp maps’ for the Western Front in1917, but the General Staff would not hear of it(D. Fletcher pers. comm., by e-mail). As a result,there were many occasions where attempts weremade to use tanks over the most unsuitableground, one example being the Canadian assaulton Vimy Ridge during the Battle of Arras in1917 where Fletcher (2004) records that all thetanks were bogged down before they could getinto action.

At the end of World War I, the impetus fortank design passed to the USA. Here, J. WalterChristie put forward and later patented (1931)ideas for the use of flexible tracks, with some formof suspension, on either side of the tank body.This gave rise to the basic design that is still inuse today on both military and civilian trackedvehicles. The layout enabled many different formsof track design to be used with variations in suspen-sion, track width and length, type of linkage,spacing of drive, idler and bogie wheels, and soon. Little work was done by the British in the inter-war years. The tank continued to be seen largely inits World War I role as an infantry support weaponso there was little incentive to improve cross-country performance.

Going maps

‘Going’ or cross-country trafficability maps werefirst used by the British Army in Egypt and Libyaduring the Western Desert campaign of WorldWar II. According to Major General F.W.(‘Freddie’) de Guingand (1947, pp. 146–148),these maps were prepared by staff at Middle EastIntelligence. They were based on local pre-warknowledge, published sources, air reconnaissanceand, in particular, reports received from the oper-ations of the Long Range Desert Group (LRDG),who included terrain assessment as part of theirduties. The Group was fortunate in having Colonel(later Brigadier) R.A. Bagnold as its CommandingOfficer (Miller et al. 2009). Bagnold, a formerSignals Officer, had retired from the Army in 1935and both before and after that date had spent aconsiderable amount of time exploring the LibyanDesert, eventually becoming the recognized worldauthority on the movement of desert sands(Bagnold 1941). He returned to the forces in 1940and was able to persuade General A.P. Wavell(later Field Marshal the Earl Wavell) of the needfor a deep reconnaissance force.

Bagnold quickly recruited two other Britishdesert veterans, Captain (later Lieutenant-Colonel)P.A. Clayton and Lieutenant (later Major) W.B.Kennedy Shaw, with the rest of the Group beingmade up of about 150 New Zealand volunteers,mostly with a rural background and selected fortheir aptitude for maintaining and using machineryin the field (Miller et al. 2009). Kennedy Shaw,who acted as LRDG Intelligence and Chief Naviga-tion Officer, notes: ‘Nothing in the way of intelli-gence interests the modern commander more than‘going’. In the LRDG no question was asked [of]us more often than ‘what’s the going like there?’(Shaw 1945, p. 26).

‘Going’ maps were drawn at a scale of 1:500 000with ground conditions colour-coded under fourheadings: ‘good’, ‘fair’, ‘bad (reconnaissance essen-tial before movement)’ and ‘generally impassable’,with supplementary comments such as ‘very goodhard sand’ added to the map (Anon. 1952, plate11). De Guingand (1947, p. 148 and maps 16 &17) comments on the effectiveness of these mapsand notes that deliberately falsified copies wereallowed to fall into Axis hands prior to the SecondBattle of El Alamein and that this had a considerableinfluence on the outcome of the operation, a viewsupported by Alexander (1948), although others(e.g. Walker 1967, pp. 111–112; Barnett 1999,p. 263) have disputed this conclusion. Going con-ditions in the desert were largely independent ofthe weather, but de Guingand (1947, pp. 210–212,map 23) also notes that operations were halted ontwo occasions due to sudden rainstorms.

D. A. GREENWOOD162



De Guingand served as Chief of Staff to GeneralB.L. Montgomery (later Field Marshal the ViscountMontgomery of Alamein) in the British 8th Army,and continued in the same role in 1943 when Mon-tgomery assumed command of the British 21 ArmyGroup, tasked with preparing the way for the inva-sion of Europe. Both men had a wide experienceof tank warfare, with Montgomery famous for com-manding battles from a tank and for wearing a blackberet with the badge of the Royal Tank Regimentnext to his British General Officer’s badge. Thisknowledge clearly had an influence on subsequentevents. Members of the Mud Committee were alsoaware of the North African experience (MC 93)and recorded that ‘In the course of the campaignsin the Middle East ‘Going’ maps were used, but,owing to the arid conditions, soil was not consideredto be a vital factor in their preparation. As far asis known no soil classification was adopted forthis purpose’.

Precursors to the Mud Committee

Events leading up to the establishment of the MudCommittee were summarized in a report byLieutenant-Colonel D.R. Skinner of the School ofTank Technology (STT) issued in May 1944 andsubsequently reprinted as Report MC 8 in August1944. As its title suggests, the report was notrestricted to considerations affecting trackedvehicles but looked at the mobility of vehicles as awhole. Skinner began by contrasting the use ofmeteorological advice by the three services as anaid to their operations and in particular highlightedthe use of specialist meteorological officers by theRoyal Air Force (RAF) at every operationalstation. He suggested that a similar arrangementwould be of benefit to the Army and would resultin the effects of weather on tank going being fore-cast by scientific means. This approach had thesupport of the Intelligence Section (Operations)(IS (O)) of the War Cabinet, who envisaged thepreparation of ‘tank going maps’ in a similar wayto soils maps that had been prepared to guide siteselection for aerodrome construction.

Proposals from STT had been forwarded to IS(O) ‘about Christmas 1943’ and this had led to ameeting held by the Inter-Service TopographicalDepartment (ISTD) on 16 February 1944 at whichISTD proposed that the expression ‘tank going’maps should be discontinued and be replaced by‘soil maps’. The maps should have a legend thatshowed the deterioration in the resistance of thesoil due to the weather and the comparative per-formance of various tracked or wheeled vehicles, apoint also later made by Kirkaldy (1948). Inaddition, soils should be classified in some way.

The basic soil map would then be overlaid by asimple tracing showing: (i) good going; (ii) fairgoing; (iii) fair going but locally bad after heavyrain; and (iv) poor going but locally passable.(This fourfold classification reflected the simplifiedscheme used in the North African campaigns.) Itwas anticipated that the going classification wouldbe amended as required on the basis of meteoro-logical reports on a day-to-day basis. This contactbetween STT and ISTD is confirmed by Farrington(1946 p. 23).

Skinner then reviewed the factors involved inthe problem under the headings: (i) topographyand geology; (ii) meteorology (field capacity, rain-fall and evaporation, and weather forecasts);(iii) physical properties of soils (including veg-etation); (iv) vehicle characteristics; and (v) furtherinvestigations – soil examinations. He noted underthe last heading that ‘It is necessary to co-relateactual performance of wheeled or tracked vehicleswith the data obtained by soil reconnaissance’.The report continues with a full review of the theor-etical considerations involved in the problemincluding the classification of soils, noting (p. 10),‘The soils shewn on the soil maps prepared by theInter-Services (sic) Topographical Department are:(1) soil on Chalk; (2) Sand and Gravel; (3) Loam;(4) Clay; (5) Clay with Flints; (6) Alluvium; (7)Peat; and (8) Marsh’. This was clearly a simplifiedscheme with operations in France very much inmind and reflects the need, highlighted by Rose(2012), for geological information to be madeavailable to the non-specialist in an easily under-standable way. Ideas borrowed from soil mechanicsand how they might be used in connection with tanktrack resistance are then discussed in detail, andillustrated in appendices giving results of recentfield trials carried out at the Armoured FightingVehicles School (AFVS), Bovington, with Crom-well, Churchill (Fig. 1), Sherman III and ShermanV tanks, and at REME School, Arborfield, on awider variety of vehicles.

The report lists ten areas where trafficabilityforecasts might be required and concludes by pro-posing the establishment of ‘Trafficability Sections’whose duties would be ‘to produce reliable fore-casts of trafficability in the field, to be able to giveimmediate answers on day to day problems andto collect any further information necessary toincrease the accuracy of the results’. It was envi-saged that the section would act at HeadquartersArmy Group level and would consist of a Head ofSection, two officers (Army or RAF) to interpretmeteorological reports, geological or soil maps andso on, with two assistants (junior officers or WarrantOfficers), at least two officers with experience oftracked vehicles to act as liaison officers, and per-sonnel for travelling soil-testing laboratories. An

THE MUD COMMITTEE IN WORLD WAR II 163



outline was then given of their duties leading tothe production of the ‘Final Going Map’. Skinnerconsulted widely in the preparation of his report,including organizations such as the Army Oper-ational Research Group (AORG); the RothamstedExperimental Research Station (RERS) (incorrectlylisted by Skinner as Rothamsted AgriculturalResearch Establishment); the Meteorological OfficeMO 9; ISTD (via the geologist Wing CommanderD.C. Ion RAF); the Road Research Laboratory(RRL); Supreme Headquarters Allied Expedition-ary Force (SHAEF); IS (O); the Fighting VehiclesProving Establishment (FVPE); the Department ofTank Design (DTD); and AFVS. Most of theseorganizations were subsequently represented on theMud Committee, often by those individuals whomSkinner had met during his research, for exampleKirkaldy, Markwick and Schofield (Table 1).

As Skinner pointed out, tank trafficability inNW Europe would be influenced not only by thenature of the ground but also by the weather andconsequently soil moisture. This led to a specialinvestigation by staff of Department MO 9 of theMeteorological Office into the effect of the weather,and in particular rainfall, on the properties of soil.A report by F.K. Hare and Flight Lieutenant (laterSquadron Leader) J.F. Kirkaldy examined the rela-tionship between soil and the underlying geology,the general physical and drainage properties of

soil, and the influence of topography, emphasizingthe importance of the water table in the developmentof spring lines. Having reviewed the evidence indetail it arrived at a simplified description for thebalance between soil water content, run-off, evapor-ation and rainfall that included the concept of soilhaving a ‘field capacity’ beyond which no furtherwater could be absorbed (Fig. 2). From this theyderived an idealized model for the soil water cyclefor an imaginary year in the northern hemisphere.This began with a winter season when the soilwould be saturated, a drying season when evapor-ation generally exceeded normal rainfall, a sum-mer season when the soil remained dry in all butthe most exceptional circumstances, a wettingseason during which the soil moved back to fieldcapacity, and a return to winter saturation (Fig. 3).They noted that conditions were particularly trea-cherous during the drying season when the soilcould quickly become saturated. The report wasinitially issued with a ‘Restricted’ classificationand does not contain any reference to the reasonbehind the study. However, in a later paper Kirkaldy(1948) repeats the overall conclusions and statesthat the object of the investigation was tank traffic-ability. He also notes that the soils information wasbased on studies at the Rothamsted ExperimentalResearch Station by Penman & Schofield (1941).As with many wartime reports, that by Hare and

Fig. 1. A World War II Churchill tank in action in March 1945, belonging to the British 6th Guards Tank Brigadebut carrying troops from the 17th US Airborne Division. Note the presence of nine bogie wheels, the wide tracks andhigh angle of attack that gave this vehicle its superior soft ground performance despite having a weight in excess of39 tonnes. Detail from BU 2739 courtesy of the Imperial War Museum.

D. A. GREENWOOD164



Kirkaldy is undated save for a reference code at thefoot of each page to ‘5/44’ and the fact that a copywas accessioned by the Meteorological OfficeLibrary on 1 August 1944. Nevertheless, it mustpre-date the formation of the Mud Committeebecause there is a later comment that this workshould continue in parallel with that of the Commit-tee (MC 42).

Another early report was prepared by BrigadierW.M. Blagden (note not ‘W.E.’ as shown in the

report; Anon. 1949a), Deputy Director-General ofFighting Vehicles in the Ministry of Supply, entitledThoughts on the bogging of tracked vehicles, dated31 May 1944; this sets out the main elements ofthe problem. Major C.W. Hoad (Secretary to theMud Committee) commenting on this report inJuly 1946 noted that it ‘. . . should logically havebeen issued as the first of all the M.C. papers as itinspired the subsequent interest in mud-crossingmatters within the Ministry of Supply and helpedto bring about the formation of the ‘Mud Commit-tee’ . . . It is suggested that this paper should befiled with M.C.1, to which it is related’ (Hoad1946). The report can now be found as a supplementto Report MC 1 as Report MC 1(x) and is a fineexample of clarity of thought.

Blagden reduced the problem to its three basiccomponents. The first was sinkage, which herelated to the load on the soil, which was in turn con-trolled by the total weight of the vehicle, number ofbogies, diameter of bogies, spacing of bogies, trackwidth and track pitch. This made the calculation of

Fig. 2. The approximate proportions of the differenttypes of soil water. For a heavy soil the horizontal linerepresents 15–40 in (380–1016 mm) of rain. FromKirkaldy (1948, fig. 1). Copyright, and courtesy, of theRoyal Meteorological Society.

Table 1. Committee on Mud Crossing Performance of Armoured Fighting Vehicles (list of members)

Name Organization Jul 1944 Dec 1945

Mr. S.A. Wood (Chairman) Directorate of Tank Design †Fighting Vehicle Design Department †

Lieutenant Colonel C. Hunt Directorate of Tank Design †Lieutenant Colonel E. McEwen Directorate of Tank Design †

Fighting Vehicle Design Department †Major C.W. Hoad (Secretary) Directorate of Tank Design †

Ministry of Supply †Colonel R.G. Shaw Fighting Vehicle Proving Establishment †Lieutenant Colonel E. Ward Fighting Vehicle Proving Establishment †Lieutenant Colonel J.R.W.

MurlandFighting Vehicle Proving Establishment †

Lieutenant Colonel D.R. Skinner School of Tank Technology †Mr. E.W.E. Micklethwait School of Tank Technology † †Colonel O.M. Solandt Army Operational Research Group †Major D.H. Parkinson Army Operational Research Group †Mr G.G. Sherratt Army Operational Research Group †Mr S.J. Wright National Institute of Agricultural

Engineering†

Dr R.K. Schofield Rothamsted Experimental Research Station † †Mr A.H.D. Markwick Road Research Laboratory † †Major E.L. de la Rue Inter-Service Topographical Department †Major J.L. Farrington Inter-Service Topographical Department † †Mr T.A. Swinden Ministry of Supply †Flight Lieutenant J.F. Kirkaldy Meteorological Office †Major H.R. Hockley War Office †Brigadier R.M. Jerram, DSO, MC Assault Training & Development Centre †Mr S.M. Edge T.T.2., Euston House, London †

Fighting Vehicle Design Department †Brigadier J.E. Hollebone War Office †Mr D.M. Wilcox (Vice-Chairman

and Project Engineer)Ministry of Supply † †

Source: July 1944, MC 42 in WO 194/829; December 1945, MC 106 in WO 194/881.




the effective load very difficult and he concludedthat it was certainly not simply the product of thevehicle weight divided by the track area. Thesecond was tractive resistance, where the questionof track length v. track width and the ground clear-ance of the belly of the tank was fully discussed. Thethird was adhesion, where the role of soil frictionand the effect of shear strength on the use andspacing of spuds (extensions fitted at right anglesto the face of the track) and grousers (lateralextensions to the outside edge of the track) wereexamined.

Blagden concluded that (i) the conventionalcalculation of ground pressure was of little value;(ii) a wide track is preferable to a narrow track;(iii) increasing the number of bogies is ineffectiveunless the diameter can be kept large; (iv) rearbogies should be more heavily loaded than frontones; (v) higher speeds favour less sinkage andbetter grip; (vi) spud spacing should be reasonablylarge; (vii) the superior performance of the Church-ill tank was due to its compliance with points i–vi;

and (viii) the A.41 was likely to be inferior tothe Churchill. The report then recommended thatfurther research should be carried out on the pro-perties of different types of boggy ground, a pro-gramme of static load tests using actual track on avariety of types of ground, and a series of dynamictrials with actual vehicles. Blagden’s work wasreviewed by Hoad in the light of earlier work in areport dated 16 June 1944. He concluded thatthere were considerable variations in the views ofother authors and this led directly to the formationof a committee, initially known as the ‘Bog Cross-ing Committee’. Hoad’s report was subsequentlyfiled as Report MC 1.

There was also a report submitted by Mr E.W.E.Micklethwait (STT) entitled Soil Mechanics inRelation to Fighting Vehicles dated 1 March 1944.This report is referred to in other Mud Committeepapers, and is included in the list of reports asMC 7 in Appendix B of MC 42. Unfortunatelyit was not archived along with other Mud Commit-tee papers in 1992, which run from MC 6 in WO

Fig. 3. The soil moisture cycle during an imaginary year in the northern hemisphere. From Kirkaldy (1948, fig. 2).Copyright, and courtesy, of the Royal Meteorological Society.

D. A. GREENWOOD166



194/796 to MC 8 in WO 194/797. However, thereis a precis of this work in MC 3. This notes that (i) anunderstanding of soil mechanics was important forthe investigation of rolling resistance on softground; (ii) current assumptions for the assessmentof ground pressure are entirely without foundation;(iii) the characteristic mechanical properties ofsoils were briefly outlined; and (iv) there was aneed for experimental work. In a note attached toMC 3 (p. 6), Micklethwait stressed that currentarguments regarding track width were irrelevantbecause the answer depended on the nature of thesoil. It was therefore essential to collect data as towhich soil conditions were of operational impor-tance. There is also a reference in MC 3 to afurther work by Micklethwait, Tracks for FightingVehicles (written June 1943–June 1944 but onlyavailable in draft form at the time). This workdoes not appear to have been included in the MudCommittee’s papers. These early reports alsoprovide evidence of contact with personnel in theUSA with an interest in the subject (MC 26).

The Mud Committee

Personnel and geological representation

The initial membership of the Committee is shownin Table 1. Of the 22 members, 14 came from amilitary background and eight were civilians, butat least two of the military representatives wereonly in the Services as a result of the wartime emer-gency. Ten members of the Committee were tankspecialists, four had administrative roles in theCivil Service, two each came from specialist mili-tary units (AORG and ISTD), and one each camefrom the fields of agricultural engineering, meteor-ology, road construction, and soil science. Thiswide range of expertise clearly created some ini-tial problems because at an early stage the Secretaryof the Committee (Hoad) noted in Report MC 16,‘At the last committee meeting it seemed apparentthat some members not intimately connected withtank problems were under some mis-apprehensionsboth as to the conditions which a tank may beexpected to work in and the factors that fundamen-tally govern traction’.

Two members of the Committee had been pro-fessional geologists prior to War World II andresumed their civilian careers shortly afterwards.Captain (later Major) J.L. Farrington had been aneconomic geologist (Farrington 2009a, b), whileFlight Lieutenant (later Squadron Leader) J.F.Kirkaldy had been an academic. By 1944 Farringtonwas Head of the Geological Section of ISTD anddetailed accounts of his career have been given byRose & Clatworthy (2008a) and Rose (2008).Farrington himself (1946, p. 24) comments on the

relationship between ISTD and the Mud Committeenoting: ‘The meetings of the Committee . . .afforded an excellent opportunity of contactingauthorities and units concerned with soil problems,in fact many of the most valuable of the Section’sassociations resulted from these meetings’. Apartfrom advice on geological and soil problems,Farrington also notes that the Geological Sectioncontributed to the reconnaissance of suitable sitesfor tank trials, the inspection of tank bogging sitesin Germany, and the preparation of a soil classifi-cation for military purposes (see below).

The World War II career of Kirkaldy is less wellknown. His obituarists (JMH 1991; Middlemiss1990a, b) refer only to his service as a meteorolo-gist and one (Moody 1990) makes no comment onhis wartime work. Kirkaldy graduated from King’sCollege, University of London, in 1929 with FirstClass Honours in geology and lectured at bothKing’s and University College, London, until 1939.His research interests were in the Cretaceous andCenozoic stratigraphy and the geomorphology ofSE England. He was unable to find geologicalemployment during the war and instead joined thecivilian staff of the Meteorological Office wherehe received full training as a weather forecaster.On 1 April 1943 he was commissioned in the Mete-orological Branch of the Royal Air Force Volun-teer Reserve (along with many others of thecivilian staff including the late S.H.U. Bowie)(Anon. 1943) and was elected a Fellow of theRoyal Meteorological Society (F.R.Met.S.) in thesame year (M. Walker pers. comm., by e-mail). In1944 Kirkaldy was selected for ‘special duties’and joined the Special Investigations Branch(Department MO 9) of the Air Ministry (Farrington1946, p. 22). In a brief reference to this, Kirkaldy(1947) noted ‘In the branch of the Meteoro-logical Office that dealt with the effect of weatheron operations, we also had many nasty questionsto answer’.

By the time the Mud Committee was formed,therefore, Kirkaldy was both a fully qualifiedgeologist and meteorologist, probably a uniquecombination of skills, covering precisely the areahighlighted by Skinner in MC 8. This explainswhy Kirkaldy was subsequently posted to HQ 21Army Group in Germany in early 1945, wherehe is believed to have provided advice direct toField Marshal Montgomery (Mrs A. Crowtherpers. comm., by e-mail). This is supported by thefact that a well-used Soils Map (currently withthe author) covering the area of the Rhinecrossing by 21 Army Group in March 1945 (Oper-ations Plunder and Varsity) and marked ‘S/LKirkaldy’ was found amongst his papers (Green-wood 2009). The significance of this map isdiscussed later.




Terms of reference

The terms of reference of the Mud Committee areset out in its first Interim Report (MC 42):

(1) The Committee will investigate the effect ofsoil characteristics on the performance oftrack-laying A.F.V.s in general, and the per-formance of such vehicles over soft mud orboggy ground in particular.

(2) The Committee will investigate the effect oftrack, bogie wheel and suspension character-istics on the performance of track-layingA.F.V.s crossing mud or boggy ground andwill make such recommendations for theimprovement of the design of these com-ponents as it considers necessary, bearingin mind the possible loss of hard-ground per-formance.

(3) The Committee will investigate the methodnow used for the calculation of groundpressure of track-laying vehicles and will rec-ommend an alternative method, should suchbe deemed necessary.

(4) The Committee will investigate any otheraspects of the design of track-laying A.F.V.swhich in its opinion affect the performanceof such vehicles when crossing soft mud orboggy ground.

(5) The Committee will initiate and supervise thecompletion of such laboratory and field testsas, in its opinion, are relevant to the generalinvestigation.

(6) The Committee is authorized to co-opt theassistance of such persons, firms and compa-nies or research institutions and organizationsas, in its opinion, can assist in these investi-gations. Financial approval must be soughtfor the expenditure of funds not already auth-orized under appropriations of organizationsrepresented on the Committee before financialcommitments are made.

(7) The Committee will report direct to Mr. A.R.Code, Deputy Director General (Engineering)A.F.V. Division, M[inistry] of S[upply],Room 535 B2. Extn. 2918, Adelphi.

Applicability of soil mechanics

The First Interim Report of the Committee exists intwo forms that vary considerably in detail. The firstis in MC 38 and is labelled as a ‘Draft’, whereas thesecond, in MC 42, dated 31 October 1944, appearsto be the final version and notes that the Committeeand its two working sub-committees (the Soil andthe Test Equipment Sub-committees) had heldnine meetings. Work had begun with a literaturesearch for all soil mechanics papers that mightseem relevant to the problem of tank trafficability

starting with a paper by Minikin (1944). This hadled to a review of papers published by Piette(1944) and Scott Blair & Veinoglou (1944) and tomore general works (not cited in detail) by Boussi-nesq (theory of pressure distribution), Golder(ultimate bearing pressure with rectangular foun-dations), Keogler and Scheldig (‘Bulb of Pressure’theory), Krey (‘Earth Cone’ theory), Terzaghi(pressure intensities with semi-rigid footings inplastic soils) and Vierendeel (‘Lateral Flux’ theory).This search was largely unsuccessful because of thecomplete difference in the situation faced by thetank designer in comparison with that of the civilengineer. In particular the Committee noted that‘There seems to be a dearth of knowledge of thereaction of soft soils to a moving vehicle and howthis is affected by the characteristics of the suspen-sion and the track’.

These conclusions are set out in Appendix A ofMC 42 which notes that almost all work publishedon soil mechanics to date had been from the pointof view of the civil engineer interested in high-ways or foundations and any conclusions reachedhad to be accepted with considerable reserve. In par-ticular it was highlighted that: ‘(a) The civil engin-eer is mainly interested in sinkage that may occurover years or centuries, whereas a track will beclear of a piece of ground in seconds or fractionsof a second; (b) The civil engineer will normallyremove the top layer of soil, whereas the trackdesigner must cater for an upper layer either in thenatural state or broken up by heavy traffic or cultiva-tion or compacted by light traffic; (c) The civilengineer is mainly concerned with large generallyrigid footings, whereas the track is small and flex-ible; (d) The soil under a foundation is static andrelatively firm, while that under a tank is disturbedand may be quite soft; and (e) In the case of a build-ing the resultant forces are vertical, whereas thetrack has to produce tractive effort to propel thevehicle forwards’.

In particular in relation to item (c) the Commit-tee drew attention to the complexities of the inter-action between a tank track and the ground, notingthat the track consists of a series of individuallyloaded shoes. Furthermore the load on each shoe,or a series of adjacent shoes, will depend on thediameter of the wheels on the tank. There was alsothe added complication of there being an invertedcatenary in the track in the spaces between thewheels where the track was not being loaded. Thiseffect was subsequently confirmed experimentallyby trials with Crusader and Churchill (Fig. 1)tanks using a piezo-electric pressure gauge underthe track (MC 60). The test did not provide an absol-ute value for track loading but did reveal five dis-tinct maxima where the load rose to three timesthe mean for the five-wheeled Crusader and nine

D. A. GREENWOOD168



times for the nine-wheeled Churchill. In the case ofthe Crusader, the load between the five maxima fellto almost zero under the inverted catenary. In con-trast, the ground loading beneath the Churchillwas much more uniform, particularly at speed, andthis correlated with the known better soft groundperformance of this vehicle. The soil was testedfor average dry density, average moisture content,liquid limit, plastic limit and compressive strength.The site of the trial is not given, but it is notedthat the soil was ‘Harmondsworth brickearth – anunsaturated silty clay’, which suggests the locationwas the RRL. This is confirmed by subsequentwork by Giles (1945). Giles was never a member ofthe Committee but some of his work was includedin their reports (MC 74, 75 & 105) and much laterformed the basis of further work by Rowland(1972a, b), who developed the ‘mean maximumpressure’ criterion that is still in use today forthe design of military tracked vehicles in the UK(Ogorkiewicz 2002, p. 144). The catenary effect wasin turn influenced by track tension, which gave riseto a more ‘girder’ like track as the tension increased.The presence, absence, design and spacing of spudsattached to the track also gave rise to lateral shearforces that were absent in the civil engineering situ-ation. It is not surprising, therefore, to find that awide variety of formulae for the calculation ofground pressure had been proposed in the pastby members of the Committee and others includ-ing Hollebone, Blagden, Skinner, Micklethwait andHoad (see MC 38 pp. 15–16) and that there was nogenerally agreed solution.

In spite of these reservations, the Committee feltthat soil mechanics had a part to play, especiallywith regard to methods of testing and identifyingdifferent types of soil, and that the principle oftreating soil as an engineering material, capable ofresisting applied stress but subject to failure, wassound and provided a way forward. In particular,properties such as the shear strength and the bear-ing capacity of the soil would clearly have an influ-ence on sinking and the loss of adhesion. Some ideaof the complexity of the task facing the Committeecan be seen from Report MC 16, in which Hoaddefined 44 factors under seven separate headingsthat needed to be correlated, and asked for com-ments. These ideas were followed up in ReportsMC 20, 26, 60, 73 and 95, which highlighted furtherproblems due to the lack of data. For example,Macey in MC 73 reviewed the known plastic prop-erties of clays based on information from the cer-amics industry and noted ‘Essentially the problemsinvolved in the sinking of tracked vehicles intomud have no known parallel in any industry’. Heconcluded that the problem did not lend itself tomathematical treatment and that empirical methodswould have to be employed. Similarly, MC 95

discusses earlier work (not cited) carried out in theUSA by M.L. Nichols in 1932 on the shear strengthof plastic soils and illustrates how wide the Commit-tee went in its search for information.

The research programme

In the absence of the information outlined above,the Committee embarked on its own research pro-gramme. This was divided into long- and short-termobjectives taking full account of the need for quickresults that could be immediately applied to currentoperations that by now were taking place in the‘wetting’ and ‘winter’ seasons identified by Hare &Kirkaldy (1944). For example, on 13 September1944 Ward (in MC 28) notes: ‘. . . the Committeewill have failed in its duty if the end of the war isreached before any practical proposals are made,as it is almost certain to be before the comprehen-sive full programme has been completed’. The long-term programme as outlined in MC 42 envisagedexamining sinkage, adhesion and rolling resistancein relation to all possible variations in track designand ground conditions with the proviso that the pro-gramme should be flexible enough to allow promis-ing lines to be examined in detail. The second areaof interest was the problem of forecasting vehicleperformance by the provision of soil maps andmeteorological data. Here, the Committee notedthe work already being carried out by STT,AORG, ISTD and MO 9 and restricted its own con-tribution to correlating vehicle performance withsoils data.

It was recognized that some time would elapsebefore the results of the full research programmewould become available and a short-term plan tomake minor modifications to existing vehicles(e.g. Sherman, Churchill and Cromwell or Comettanks) was drawn up. This was agreed at thefourth meeting of the Committee on 18 October1944 and is described in Appendix E of MC 42.The principal long-term research areas were to be(i) static tests; (ii) one-third scale mobile rig tests(outlined in Appendix C of MC 42); and (iii) full-scale tests. The latter two required the provision ofeither natural or artificial test sites. It was proposed,therefore, to examine various coastal areas and toconstruct an artificial ‘soil bath’ at FVPE,Chobham (Appendix D of MC 42). The need forimproved instrumentation was noted, in particularthe development of a satisfactory transmissiondynamometer so that the results of trials could berecorded in quantitative terms. There was also aneed for some form of instrument to rapidly assessthe ability of soft ground to support given vehicles.The report concludes with a series of interim rec-ommendations and opinions that it recognizedwere not as yet based on experimental evidence.




These may be summarized as the following: (i)improvements in soft ground performance werelikely to be at the expense of other factors; (ii) soilproperties were complicated by variations in thesoftness profile with depth; (iii) if possible, thisvariation should be incorporated into soil maps;(iv) the best soft ground performance from a flexibletrack would come with the load distributed aswidely and evenly as possible; (v) a rigid girdertrack would provide the best pressure distributionalthough its limitations were recognized; (vi) along track pitch favours soft ground performance;(vii) the current simple formula of vehicle weightdivided by total track area was inaccurate in asses-sing loading; (viii) maximum adhesion depends onspud design; (ix) instruments for assessing bogshave yet to be tested; and (x) a long narrow trackwould be best in soft mud with a firm bottom, buta short wide track would be best in really badgoing. The latter point, of course, implies that differ-ent vehicles might have to be used in differentground conditions, thereby illustrating the complex-ity of the problems facing the Committee.

The draft version of the First Interim Report inMC 38 covers much the same ground but has adifferent emphasis on individual items. In particularthe contents page of this version indicates thatthere was an Appendix D, ‘The Applicability ofSoil Maps’, attached to the original, but sadly thisis not present among the papers held at the NationalArchives. However, MC 38 does include a copyof the Full Research Plan (as fig. 1), replacingan earlier version issued as MC 5, and the Immedi-ate Expedient Plan (as fig. 2), which, for somereason, were not included in the final version ofthe report (MC 42).

The Soils Sub-committee reconnaissance

party

The long-term research programme envisaged run-ning a series of trials of different track configur-ations over a standard test area. As a result, at itsfirst meeting, the Soils Sub-committee set up aReconnaissance Party, listed in MC 62A as consist-ing of Farrington, Hockley, Kirkaldy, Markwickand Schofield from the full Committee (Table 1)and two co-opted members, Captain Williams(AORG) and Captain (later Major) D.R.A. Ponsford(ISTD).

The party immediately set about looking forsuitable test sites with the following requirements:‘(a) It should have an area equivalent to a squareof not less than 400 yds. [365 m] side; (b) It shouldbe as flat as possible; a slope of 28 would be toler-able, provided it is free from local variations in thesurface; (c) It should be devoid of vegetation as

far as possible; (d) The soil should be homogeneousin depth to approximately 36 ins. [914 mm] andhave a slow variation across its area to give a varia-tion in going from good going (i.e. sinkage approxi-mately 3 ins. [76 mm]) down to complete bogging;and (e) The soil should be clay or silt’.

It was felt that these could be met by a suitablecoastal location where ground conditions would becontinually renewed by the action of the tide. Alist of potential coastal sites was put forward inMC 25, which records neither the author nor theoriginating organization. However, both MC 41Aand Appendix B of MC 42 show it was the workof ISTD, as does a remark by Farrington (1946,p. 24). The sites were examined by an aerial sur-vey between 21 and 26 September 1944 using aFairchild flying out of Air Transport Auxiliary(ATA) Command Headquarters, White Waltham,Berkshire, with the flying conditions being recordedas ‘100–500 ft at 80 m.p.h.’. No further details aregiven of the aircraft but it is likely to have been aFairchild F24, known to the RAF as the Argus.This was a four-seat high-winged single-enginedmonoplane that was widely used by ATA as an‘air-taxi’ and would have provided an ideal plat-form for viewing intertidal areas. The personnelinvolved in the survey are not listed but it is signif-icant that Farrington did have prior experience inthe use of air surveys (Farrington 1936).

The air survey (MC 41A) identified five sitesdefined as ‘promising for large scale trials’ from atotal of 27 put forward by ISTD, but the Reconnais-sance Party did not accept this limitation andincluded a further eight of the original sites forsurvey on the ground. They also added three moresites that had not been identified by the aerialsurvey, making a total of 16 in all (Table 2).These were investigated in the period up to 12January 1945 and are listed in MC 62A as being inReports MC 24, 37, 45A, 49A, 51A, 52A, 58Aand 59A. However, MC 37 and MC 45A are dupli-cates of the Humber Estuary reports, and the infor-mation for Grangemouth on the Firth of Forth andWelsh Banks on the Severn Estuary, which shouldbe in MC 37, is missing.

The additional three sites were at Brancaster(MC 52A), Appledore and Poole (both MC 24),the latter two having been put forward byHockley. These sites are interesting because theyhad been used in some way in the preparations forOperation Overlord, but to date no reference tothis earlier work has been found in any of the MudCommittee papers. The Committee as a wholeappears to have been unaware of this earlier activ-ity, although at Brancaster it was noted that tankscould run and bog on the clay (MC 62A), and thesite inspection (MC 52A) noted ‘clay outcropshave been torn by previous passage of tracked

D. A. GREENWOOD170



vehicles and H. E. shells’. The work done on vehicletrafficability at Brancaster (Rose & Clatworthy2008b) and on the Normandy beaches (Rose &Pareyn 2003), mainly by Major (later Professor)F.W. Shotton in the run up to D-Day, does notseem to have been made available, despite beingparticularly relevant to this aspect of the Commit-tee’s investigation, and the fact that somemembers of the Committee, notably personnelfrom ISTD (Farrington 1946, p. 26), were probablyaware that it had been carried out. Such was thesecrecy imposed at the time.

The search for coastal sites occupied a great dealof the Reconnaissance Party’s time in the autumn of1944, with each location being assessed under thefollowing headings: (i) accessibility; (ii) ground;(iii) location; (iv) remarks; (v) site details; (vi) veg-etation; (vii) soil profiles; (viii) moisture content;(ix) penetrometer; (x) unsupported compression;(xi) shear box; (xii) recovery; (xiii) other features;(xiv) administration; and (xv) suitability. Unfortu-nately despite this major effort, none of the selectedsites proved to be suitable for tank trials althoughsome were already in use for military purposes. Aninland trial on a large clay dump at the HorshamWorks of the Sussex Brick Company had also beenunsuccessful due to the variable nature of the ground.

The situation was reviewed at what must havebeen somewhat of a crisis meeting on 9 January1945 (MC 62A) attended by members of the Recon-naissance Party (Parkinson and Schofield, theco-opted members Ponsford and Williams and onenew member, Arney, from AORG) together withfour members of the main Committee (Hoad,Swinden, Ward and Wood). Apologies for absencewere received from Farrington, Hockley and Mark-wick, and it was noted that Kirkaldy (incorrectlyshown as Kirkcaldy) was unable to attend due tobeing on duty in France. The meeting decided tolook for inland sites consisting of clay, alluviumor heavy loam for the urgent small-scale trials thatwere needed to test short-term modifications, andit was noted that this should be on ground thatwould reflect current battle conditions. The searchfor suitable sites to obtain fundamental informationfrom large-scale trial sites was to continue, but thegeneral tone of the report suggests that it was feltthat such sites were unlikely to be found. Sitesimmediately identified for possible small-scaletrials were on the Somerset clay, near Bridgwater(incorrectly shown as Bridgewater), and low-lyingcountry around Pulborough, Sussex. These wereto be reconnoitered by FVPE with assistancefrom either RRL, RERS, AORG or ISTD. Thesearch for long-term sites was to continuethrough AORG, with the examination of furthercoastal sites in southern England including theNorfolk Broads and areas around Portsmouth and

Southampton (the latter two presumably havingbeen excluded from the original search due to therisk of enemy action).

The proposed soil bath and other trials

The failure to find a suitable site for large-scale trialsby January 1945 was a serious set back for thelong-term research programme of the Committee,which had to be put in abeyance due to the impera-tives of war. Instead, the Committee turned its atten-tion to the possibility of qualitative trials involvingthe use of an artificial ‘soil bath’ and other sitesfor comparative tests. The artificial soil bath wasto be established at the FVPE at Chobham andwould consist of a concrete lined bath 30 m long,9 m wide and 1.8 m deep (100 × 30 × 6 ft) withadditional ramped ends 9 m (30 ft) long. Panelswithin the bath would allow it to be divided into sec-tions and the whole was to be covered by steel-framed asbestos sheeting. Water from a controlledsupply would be directed to six points on eachside of the bath (see MC 42, Appendix D). Thisfacility was not built and discussions were still inprogress as late as 1946 (MC 106 and 111).However, a natural facility was made available atAlbery Bottom on Chobham Common consistingof waterlogged loam, sand and clay with an under-lying bed of firm clay.

Comparative trials were carried out on a ‘go, nogo’ basis similar to those being used by the USArmy (MC 66). The American research at a testfacility at Yuma, Arizona, looked at the problemsof crossing rice paddy fields and differed fromthat of the Mud Committee in two importantways. First, the trials covered all vehicles (bothtracked and wheeled) and, second, the object ofthe research was to identify what type of additionalartificial roadway might be required rather thanlooking at soil properties. It was found that, ingeneral, tracked vehicles had no problems in thiskind of terrain, but wheeled vehicles required someform of artificial mat. A 23-page booklet describingtrack modifications for use in mud crossing cover-ing landing vehicles, crawler tractors, cargo carriersand tanks (Sherman M4 and M5) is attached tothe report.

In the British trials, illustrated by MC 61, differ-ent tanks, or the same tank with different track fit-tings, were tested under as near as possible thesame conditions and then ranked according totheir performance. A wide variety of tanks weretested, including the British Churchill, Cromwell,Comet and A33 (Excelsior), the Anglo-AmericanT14, the American Sherman, captured GermanLynx (Luchs), Panther and Tigers and the RussianT34. In a summary of the results to 24 December1944, the report ranks vehicles in the following




Table 2. List of coastal sites reconnoitered by the Soils Sub-committee

Location Details A B C

Thames Estuary Whitstable Bay W

Isle of Sheppey and Swale River † W

Gillingham Reach W

Isle of Grain W

St Mary’s Marshes † W

North Bank W

Chetney Marshes 59AStray Marshes 59AWarden area 59ALeysdown Marshes 59AHam Marshes 59AGraveney Marshes 59AThe Oaze (Whitstable Bay) 59A

Shoeburyness Maplin Sands W

Chapman Sands W

Ray Sand W

Dengie Flat W

Pigs Bay 58AShelford Creek 58AFishermans Head 58A

Harwich-Colchester area †South Blackwater Estuary † W

North Blackwater Estuary Tollesbury Fleet † W

Mersea Island † W

The Wash The Wash †Brancaster area 52AHunstanton W

Wolferton W

Breast Sand W

Wisbech Channel W

Wisbech Channel to Welland Outfall W

Welland Outfall to The Haven W

Friestone Low W

Butterwick Low W

Wrangle Flats W

Friskney Flats W

Friskney Flats to Skegness W

Northcoats area Donnanook to Northcoats W

Northcoats to Cleethorpes W

Humber Estuary Somercotes Haven †Saltfleet †Paull Home Sands W

Sunk Island † W

Welwick † 45ASkeffling Clays †Easington Clays †Kilnsea Clays W 45A

Firth of Forth Bo’ness area W

Grangemouth area † 37Culross area † W

Firth of Tay Errol †Carthagena Bank W

Dog Bank † W

Powgavie Beacon to Kingoodie † W

Montrose Montrose Basin † W

Firth of Clyde Ardmore Peninsula † W

Largs Coastal area W

Wigtown area Wigtown Sands W 51A

(Continued)

D. A. GREENWOOD172



order: Churchill, Panther, Cromwell, Sherman(Skinner Platypus tracks), Sherman (extended endconnectors), Sherman (steel chevron tracks) andTiger, noting that the Cromwell and the Shermanswere easily bogged and that the performance of

the Tiger had been very poor (MC 61 p. 13). Itwas noted that the skill of the driver had some influ-ence on the results of these trials, especially withregard to the relative performance of the Churchill(familiar) and the captured Panther (unfamiliar).

Table 2. Continued

Location Details A B C

Baldoon Sands W

Fleet Bay W

Kirkcudbright area Kirkcudbright Bay W

Auchencairn Bay W

Rough Firth W

Mersehead Sands W

Solway Firth Preston Merse †Soar Point †Wigtown Bay †Priestside Bank †Annan to Gretna †Rockliffe Marsh † † 51ABurgh Marsh †Burghley Sands to Bowness †Bowness to Silloth † 51AGlasson area 51ABrowhouses area 51AEastriggs area 51A

Millom Millom Marshes † W

Duddon Sands W

Morecambe Bay Cartmel Sands W

Kent Estuary † W

Warton Sands W

Skinburness area 51ACalvo Marsh 51ANewton Arlosh area 51A

Lune Estuary Cockersham Marshes †Ribble Estuary Hesketh Marshes/Sands † W 51A

Hutton Sands 51AMersey and Dee Estuaries Mersey South Bank W

Ellesmere Port 51ADee Estuary † W

White Sands 51AParkgate area 51AFlint area 51ABagillt area 51AHolywell Bank 51A

South Wales area Tay Estuary W

Towy Estuary W

Gwendraeth Estuary † W

Llanrhadian area W

Severn Estuary Welsh Banks † 37Portlands Nab 62A

Weston-super-Mare Sand Bay 62ABridgewater (sic) Estuary Stert Flats and other areas † W

Chivenor Horsey Island 24Appledore Skern Bank 24Poole Harbour Arne Island 24

A, original recommendation from ISTD (MC 25 in WO 194/813).B, results of Aerial Reconnaissance. W, surveyed; †, recommended (MC 41A in WO 194/828).C, report number for site inspections prior to 12 January 1945 (listed in MC 62A in WO 194/846).




This report includes references to the other testscarried out by FVPE at Leatherhead, but theseresults do not appear to have been presented to theCommittee. However, the Committee did receivereports of other field trials near Faenza in Italy inlate 1944 (MC 70), concentrating specifically onthe use of grousers on Shermans, which werewitnessed by Skinner. Soil samples taken at thetest sites were analysed by Markwick. The reportconcludes that both extended end connectors andPlatypus grousers significantly improved the per-formance of the Sherman and put it on a par withthe Churchill and Panther.

The Committee also reviewed earlier work byAORG on sinkage trials carried out in May 1944(MC 48). The trials involved running Churchill,Sherman, Cromwell and Centaur tanks over a fieldof heavy brown clay near Kilmarnock, Scotland.The report notes that this site was chosen because‘At the beginning of these trials (May 21st) theonly areas in which sufficient rain had fallen tomake conditions wet enough were in Scotland’,providing a good illustration of the difficultiesexperienced by the Committee in investigatingthe effect of the weather, and in particular rainfall,on ‘going’. The main purpose of the trial was toinvestigate the relationship between moisturecontent and sinkage and it was concluded thatthis was essentially linear, although the graphsillustrating this are not entirely convincing (MC48, figs 1–8). The soil was also tested for liquidlimit, plastic limit and plasticity index. Measure-ments were also made of unconfined compressivestrength and it was found that a curve (MC 48,fig. 10) could be fitted to the results when thisfactor was plotted against sinkage. There was littleor no sinkage at an unconfined compressive strengthof more than 20 lb/in2 (138 kPa) but sinkageincreased rapidly from 4 in (100 mm) at a value of7 lb/in2 (48 kPa) to 8 in (200 mm) at 3 lb/in2

(21 kPa). No equation was given for the curve andthis aspect was not pursued further in the report asit was noted that this was not the main point of theexperiment.

Other trials were carried out in Somerset, but thefinal report on these, unfortunately, is missing (MC82). These miscellaneous trials did not yield anyquantitative information, but gave rise to usefulcomparative data; however, they were highly sub-jective and the fact that in some cases the resultswere influenced by the skill of the driver introducedyet another variable. A further complication wasthat many of the vehicles were noted as being oldand not in the best mechanical condition. Thetrials did have the advantage of being closelyrelated to battle conditions and allowed immediatemodifications, for example in the fitting of spudsand grousers, to be carried out.

Soil maps and on-site advice

As Skinner noted (MC 8), ISTD had already drawnup an interim soil classification for use in NWEurope and by 1945 this had been extended to thatshown in Table 3, from MC 93, the anonymousauthor noting that feedback received from Shottonwas used in its preparation. This contributionis confirmed by information from Shotton’s ownnotebooks in the Lapworth Museum (Rose et al.2006, p. 140). The most useful outcome of thiswork, however, appears to have been the provisionof on-site advice by geologists in the field. Thisdid not consist of the fully fledged units as origi-nally envisaged by Skinner, but revolved aroundthe work of four men, three of whom served onthe Mud Committee. They were Shotton, as SO(2)(Geology) in 21 Army Group (Rose & Clatworthy2008a), Kirkaldy in his combined meteorologicaland geological role nominally attached to HQ 2Tactical Air Force (HQ 2TAF) but actually pro-viding advice to HQ 21 Army Group (Mrs M.R.Geeling pers. comm.), Farrington who was attachedto R.E. branch 21 Army Group from 24 December1944 to 19 January 1945 (Farrington 2009b) wherehe assisted with the preparation of soil maps andvisited various fighting units (Farrington 1946,p. 26) and Ponsford, who was posted from ISTDto 21 Army Group Rear HQ (Brussels) to assistShotton as Deputy Assistant Director of Works(Geology) on 21 January 1945 (Rose 2008; Rose& Clatworthy 2008a). Farrington also notes that‘Many telephoned requests [to ISTD] for infor-mation, chiefly regarding soils, were executed’(1946, p. 26).

The benefit of this approach is illustrated by Kir-kaldy (1948), who provides an account of the jointinspection of the ground by himself and Shotton fol-lowing unexpectedly severe bogging experiencedduring the Battle of the Reichswald (OperationVeritable) in February 1945. This was found to bedue to the presence of an unrecorded layer ofloam within an area of sand, which had notbeen marked on the soil maps. Site investigationallowed immediate revisions to be made to themaps, even extending to ground in enemy hands.

The surviving copy of Kirkaldy’s contemporarysoil map (Anon. 1944) includes references to ‘AreaFiles K/52 & K/53’, which can be related to thesheet boundaries of GSGS maps illustrated byRose & Clatworthy (2007, fig. 9). The map showsthat the simplified classification of ISTD noted inMC 8 was still in use and comparison with theplan of battle (Anon. 1947, plate 13(a)) for the cross-ing of the Rhine (Operation Plunder) illustrates howwell it was used. The Rhine at this point consists ofthe main stream to the west accompanied by a seriesof old ox-bows and channels making up the Alter

D. A. GREENWOOD174



Rhein to the east with a series of areas of slightlyhigher (up to 5 m) ground in between. The latter pro-vided the landing areas for the main crossing and

were protected from immediate counterattack bythe low-lying ground to the east. Such protectionwas not available towards the south around Wesel

Table 3. Inter-Service Topographical Department – soil classification 1945

Type No. Sub-type Notes

Sands andgravels

1 Loose coarse or medium sand Less than 30% pebbles Less than 20% materialfiner than sand of whichless than 10% is clay

1a Gravel More than 30% pebbles Less than 20% materialfiner than sand of whichless than 10% is clay

2 Compact, coarse or medium sand Less than 20% materialfiner than sand of whichless than 10% is clay

3 Fine sand Less than 20% materialfiner than sand of whichless than 10% is clay

3a Fine, windblown sand Less than 20% materialfiner than sand of whichless than 10% is clay

4 Sandy loam; very friable soils 40–80% sand5 Loam; friable soil composed of

mixture of sand and clay or silt6 Non-sticky, clay-loam; composed

of clay, silt and sandLess than 60% clay and

fine silt; more than10% coarse sand

6a Sticky clay-loam Less than 80% clay andfine silt; more than10% coarse sand

6b Boulder claySilts 7 Silt 0.02–0.002 mmClays 8 Friable clays More than 80% clay

and fine silt8a Limey clay More than 80% clay

and fine silt9 Sticky clays More than 80% clay

and fine silt9a Alkaline clays More than 80% clay

and fine siltBogs 10 Swamp and marsh soils;

permanently waterlogged11 Peat11a Peat – artificially drained

Rock soils 13 Gravel or boulder-strewn surfaces13a Mainly bare rock

Special soils 14 Highly lateritic soils14a Hard laterite at, or within, 12 in.

[0.3 m] of surface.15 Saline soils. Sodium salts15a Saline soils. Calcium salts16 Highly micaceous, sandy soils.16a Highly micaceous, loamy soils.16b Highly micaceous, clayey soils.17 Limestone soils.17a Coral sands.18 Volcanic sands.

Artificialsoils

19 Artificial soils, such as built-up,industrial or mining wastes, etc.

Source: MC 93, pp. 6–7, in WO 194/873.




Table 4. Inland sites reconnoitered by the Soils Sub-committee – November 1945

Type ISTD no.* Site no. Location NGR† Horizon (where shown) R‡

Sands 2a (i) 1 Pendell Sand Pit, Bletchingley TQ 307 524 Lower Greensand R2a (i) 2 Titsey Estate, Limpsfield TQ 427 545 Sand and Gravel2a (i) 3 Ockham Common TQ 074 591 Bagshot Beds2a (ii) 1 Pendell Sand Pit, Bletchingley TQ 307 524 Lower Greensand2a (ii) 3 Ockham Common TQ 074 591 Bagshot Beds R22a (ii) 4 St Vincent’s near Trottiscliffe TQ 641 595 Lower Greensand R12b (i) 1 Pendell Sand Pit, Bletchingley TQ 307 524 Lower Greensand R2b (i) 2 Titsey Estate, Limpsfield TQ 427 545 Sand and Gravel3a 5 Camber Sands Golf Course TQ 960 187 Dune Sands3b 6 Ryarsh near Maidstone TQ 669 605 Lower Greensand4 (i) 7 Bletchingley TQ 343 526 Lower Greensand R14 (i) 8 Esher TQ 150 654 Bagshot Beds4 (i) 9 Gatwick TQ 271 408 R24 (i) 10 Wychnour House near Battle TQ 782 1454 (i) 11 Hockenden near Swanley TQ 492 6994 (ii) 9 Gatwick TQ 271 4085 (i) 12 Henley Park near Henley-on-Thames SU 761 846 R25 (i) 13 Play Hatch near Reading SU 743 7675 (i) 14 Sheffield Park Sta. near Haywards Heath TQ 406 243 R15 (i) 15 Mountfield TQ 737 2135 (ii) 12 Henley Park near Henley-on-Thames SU 761 846 R6a 16 Patcheson Park near Leatherhead TQ 164 5976a 16 Patcheson Park near Leatherhead TQ 164 6046a 17 Holmes Hill west of Hailsham TQ 533 135 R26a 18 Pig Tor near Buxton SK 088 732 R16b 19 Peasmarsh near Rye TQ 931 222 R

Silt 7 20 Caio Forest near Pumpsaint SN 679 414Clays 8 21 Sendhurst Grange near Send TQ 032 548

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8 22 Bedford – Ampthill Rd A421 Brickworks TL 038 4638 23 North Holmwood Brickpit TQ 173 484 Weald Clay8 24 North Holmwood Brickpit TQ 166 470 Weald Clay R18 25 Beare Green Brickpit TQ 183 432 Weald Clay8 26 Blindley Heath TQ 365 457 R38 27 Iron Ore Pit 3.5 m NW of Banbury A422 SP 388 439 R29a 28 Laughton near Lewes TQ 483 118 Gault Clay9a 29 Laughton near Lewes TQ 482 114 Gault Clay9a 30 Pevensey TQ 650 0789a 31 Eccles Clay Pit near Rochester TQ 723 617 Gault Clay9a 32 Rothley – Cossinton Rd near Mountsorrel SK 593 1359a 33 NE of Killamarsh SK 456 826 Coal Measures9a 34 Bangor on Dee (Bangor-is-y-Coed) SJ 385 467 R9a 35 1 mile north of Shrewsbury SJ 493 1599b 36 Clay pit off Hope-Bradwell Road SK 176 828 Yoredale Series R39b 37 Stamford Bridge near Chester A51 SJ 465 681 R29b 38 Aldford near Chester SJ 422 6019b 39 Near Foel SH 999 113 R1

Bogs 10 40 Romney Marshes TR 025 21111a 41 Butley near Orford TM 367 52311a 42 South side of Welshpool – Cemmaes Road SH 936 13611a 43 2 miles west of Mallwyd SH 856 12111a 44 Near Dovey Junction SN 704 99611a 45 Near ‘The Arch’ south of Devil’s Bridge SN 766 76211b 46 Treflyn near Tregaron SN 688 63111b 47 Higher Wincham near Northwich SJ 700 762

*The soil classification used in this report differs slightly from that proposed by ISTD in MC 93 (see Table 3) as follows: 2a, coarse sand, loose; 2b, coarse sand, compact; 3a, fine sand, loose; 3b, fine sand,compact; 4, sandy loam; 5, pure loam; 6a, clay loam, friable; 6b, clay loam, non-friable; 7, silt; 8, friable clay; 9a, clay, sticky when wet; 9b, sticky clay; 10, marsh and swamp soils; 11a, peat; 11b, peat,artificially drained. The suffix (i) indicates a high-level (dry) site and the suffix (ii) indicates a low-level (wet) site.†National Grid References calculated from the original wartime (‘purple’) grid references using conversion formulae provided by Penny (2000) and checked on current Ordnance Survey 1:50 000 maps.‡R, recommended site. 1–n used where several sites of the same type exist to show order of preference.Source: MC 107 in WO 194/882.

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and in this case it was deemed necessary to securethe crossing with an airborne landing (OperationVarsity). The initial planning for the Rhine crossing,including an assessment of the characteristics of theriver bed, was carried out by Shotton. However, ithas been noted that he was never deployed toGermany and at the time of the actual operation hehad been demobilized and was back in England(Rose & Clatworthy 2008b). With Farrington backat ISTD and Ponsford at Rear HQ, that leavesKirkaldy as the only one of the four still in the field.

The condition of Kirkaldy’s map is interestingbecause it was clearly well used, with countlessfolds, areas that have been soiled with use and innu-merable pin holes in the corners, and it is in a statethat is clearly recognizable to any geologist whohas worked in the field. The choice of units to com-plete the breakout from the crossing was clearlyinfluenced by the projected soil characteristics ofthe ground to the east of the Rhine, with an areamarked as mainly loam or fine loamy sand to thenorth being secured by the 43rd Infantry Divisionwhile an area of mainly sandy gravel to the southwas used for the main armoured advance towardsBocholt by the Guards Armoured Division.

Postwar activities

At the end of hostilities, many members of the Com-mittee were demobilized and returned to civilianlife, but the remainder (Table 1) continued until1946. Further efforts were made to identify coastalsites for large-scale trials with a final thoroughsearch with the assistance of County Surveyors(who had not been consulted earlier due towartime secrecy) in case any had been overlooked(MC 102). The ISTD representatives on the Com-mittee continued with their work to establish a soilclassification for military purposes as proposed inMC 93. This work, together with information onsoil mechanics, soil stability, soil maps and cross-country movement, was subsequently incorporatedin the textbook Military Engineering Volume XV:Application of Geology (Anon. 1949b), whichremained in use until superseded by a new volume(Anon. 1976; Rose & Clatworthy 2008a).

This new soil classification was also used as afurther basis for locating suitable inland test sites.The requirements for these were less stringent andrequired only the following: ‘(i) Each site to havethree squares of land suitable for testing. (ii) Thesize of each square to be 15′ × 15′ [4.6 × 4.6 m].(iii) The sites to be as level as possible and themaximum slope allowable is not normally toexceed 108. As noted above, this slope had to beexceeded on one or two sites. (iv) Vegetationcover not to be heavier than normal pasture if poss-ible. (v) Access to be suitable for an ordinary farm

tractor. (vi) The sites to be selected on groundwhich stands a reasonable chance of remainingundisturbed during the full period of the tests’.Potential sites were selected by ISTD and AORG.As a result of this exercise, a total of 47 sites(Table 4) were identified and inspected thatcovered the soil types identified for NW Europe,and 19 were classed as suitable for trials, but thereis no evidence in the Committee’s papers that anyof these sites were actually used.

Members of the Committee were also involvedin the inspection of bogging sites in Germany (MC103), but unfortunately this report has not beenlodged with the National Archives. However, Far-rington (1946, p. 32) notes that ‘Captain W.E.Fraser, R.E., visited Germany with a team of theMinistry of Supply Mud Committee from 11thJune to 11th July 1945 to inspect, study and reporton sites and areas of tank bogging during therecent campaign’. A full list of all these overseasinspections (not all of which involved the MudCommittee) has also been given by Rose &Clatworthy (2008a). The Committee also reportedon the work that had taken place to develop a suit-able penetrometer to measure bearing capacity inthe field (MC 111).

Conclusions

The work of the Mud Committee was summarizedin its Second Interim Report dated December 1945(MC 106), which was, for all practical purposes,also its Final Report. The report notes that thefuture of the Committee was uncertain due to organ-izational changes affecting the departments respon-sible for vehicle research and development. Themain points covered were as follows.

Historical background

It was noted that none of the belligerents had fore-seen the need for major improvements in the softground crossing of tanks and other AFVs at the out-break of World War II and that the early campaigns(Poland – September 1939; France and the LowCountries – May and June 1940; and Libya –March 1941 to 1943) had all been fought overfavourable terrain. Setbacks during the Russiancampaign in the winter of 1941–1942 had led theGermans to investigate snow crossing, but mudcrossing as a design problem had been ignored,with the official attitude being one of avoiding theproblem. Later campaigns by the Allies, however,had been under much less favourable conditions(NW Europe – June 1944 to Spring 1945; Italy1944; SE Asia – 1943 to 1945). This had led towork not only by the British (i.e. the Mud Commit-tee) but also by researchers in the USA, Canada and

D. A. GREENWOOD178



Australia, who all appeared to have worked onsimilar lines. There had been close cooperationbetween these parties, as evidenced by the exten-sive list of papers and reports received (itemizedin Appendices B to E of MC 106) and by theaccount given of a visit to the USA by members ofthe Committee (see below).

Review of work done by the Committee

The greater part of the short-term test programmeproposed in November 1944 (MC 42) had beencompleted. In particular, the relative performanceof individual tanks and the effect of minor trackmodifications had been established with respect toitems such as sinkage and traction. Routine mea-surements of soil properties had also been made.Tests on ground loading by the RRL had establishedthat having a wide track and a larger number ofwheels were important design criteria for softground performance (e.g. the Churchill). Work onthe movement of track links had been inconclusive.

In contrast to the success of the short-term pro-gramme, the report notes that full-scale long-termtests had not commenced, although nearly all theequipment had been acquired. The mobile test rigenvisaged in the First Interim Report (Appendix Cof MC 42) was ready. However, the Soil Test Bath(Appendix D of MC 42) had yet to be built. Thesearch for field test sites in England and Waleshad been largely unsuccessful and, without excep-tion, tidal mud flats had been found to be unableto support contemporary tanks. Some progress hadbeen made in relating soil properties to mobility.In particular, work by AORG had established corre-lations between sinkage (taken as being the inverseof mobility) and both moisture content and shearstrength (MC 47 and 48), but it had been difficultto relate this to tank-going maps due to the absenceof suitable penetrometers and ‘bogsticks’ to providerapid on-site results. One of the Committee’s diffi-culties had been ‘the determination of which soilfactors are relevant to mobility’. The search for anideal ‘bogstick’ continued. Work on soil classifi-cation had advanced considerably as a result of thework done by ISTD, but the application of a math-ematical approach had failed due to the inherentcomplexity of the problem. Proposals for a one-eighth scale model dynamic rig were in hand,although it was noted that the problem of dynamicscale factors in relation to soil were much morecomplicated than those for ship models in watertanks and aerodynamic models in wind tunnels.

Visits and investigations abroad

A small party had visited the USA in March 1945and had established that work by both countries

was proceeding in a similar manner, although thedifference in organizational structure had madeliaison difficult (MC 81). There had also been aBritish Intelligence Objectives Sub-Committeeteam consisting of Committee representatives whovisited Germany in September 1945, which estab-lished that there was no evidence of any German‘Mud Committee’ and that the official German atti-tude to mud was to avoid it. The latter point possiblywas due to the inherent limitations of tracks withinterleaved wheels that were very prone to mudand snow packing (MC 104). A party drawn fromFVPE, RRL and ISTD had visited Holland andGermany in June 1945 to study sites where severebogging had occurred. Its main conclusion was thatthe alluvial soils between the Rhine and Weser wereimpassable to heavy AFVs for a few months of theyear (MC 103). The use of mobile soil testing lab-oratories or ‘soil vans’ to investigate boggingduring operations had proved impractical, andonly one had been mobilized, late in the war inItaly. There had also been occasional contact withorganizations in India (MC 19), some of whichoccurred after the Second Interim Report (MC 108).

The future of the Committee

The report notes that in view of the many Depart-ments in the separate Services concerned with themobility of tracked vehicles and the ever increasinguse of them in different terrains, there was a need fora comprehensive Inter-Service Mobility Committeethat could conduct research to fill the gap in knowl-edge of fundamental and applied ‘automotive’soil mechanics.

Conclusions regarding design

The Committee concluded that for tracks: (i) there isa definite improvement in soft ground performancefrom increased track width and adequate spudding;(ii) the combination of a reduction in groundpressure and increased spudding was more effectivethan either applied singly; (iii) the use of asym-metric track extensions (grousers) caused problemsdue to track throwing; (iv) there was some evidencethat a long track pitch was advantageous; and (v)there was no evidence that inclined or chevronnedspuds gave greater tractive effort.

Similarly, for loading distribution it was noted:(i) peak pressures under a moving track are con-siderably affected by the ratio of wheel spacing totrack pitch; (ii) uniformity of loading gives superiorperformance; and (iii) the interleaved wheelsfavoured by German designers gave rise to boggingdue to mud-packing.

Areas for further investigation included the fol-lowing: (i) there was still a need for fundamental




knowledge of the factors involved in soft-groundcrossing performance; (ii) the question of quantitat-ive assessment remained unsolved; (iii) there wasstill a need for a soil bath where full-scale trialscould be carried out under controllable conditions;(iv) research should be concentrated on ‘bottomless’mud rather than shallow mud on a firm bottom; and(v) work on snow crossing would be best left toworkers in the USA and Canada (although laterthere was contact with the Swiss; see MC 109).

The Second Interim Report was not quite thefinal word on the subject, and there are two furthergeneral reports that review the whole subject ofsoft ground performance. The first, in MC 110,

brings together the principle points ‘for the infor-mation of persons newly interested in the softground crossing problem’ and provides a list ofwhat are considered to be the key papers. Thesecond, in MC 111, dated September 1946, issimilar in nature but concentrates on soil testing. Itconcludes with the remark: ‘Active interest in thiscountry is at present limited to two or threepersons, each with other commitments. Offers ofcollaboration, advice, or of untapped informationwould be welcome’, providing a sad end to morethan two years of extended endeavour by a greatmany people, often working under very adverseconditions.

Appendix

Appendix 1. List of original Mud Committee reports

MC No. Author (where

known)

Year Title Source NA Ref.

WO 194/

1 Hoad, C.W. 1944 Transmission Branch Report No. TN 73. Bog crossing

performance of tracked vehicles

DTD 791

1X Blagden, W.M. 1944 Thoughts on the bogging of tracked vehicles MS 791

2 1944 Bog crossing performance of tracked vehicles. D.T.D.

Report No. TN 73 /1.

DTD 792

3 1944 Abstracts of Papers Bearing on soft ground performance 793

4 1944 S.T.T. Chart of factors contributing to rolling resistance STT 794

5 1944 Chobham Sub-Committee’s Proposal for Research Plan 795

6 Little, L.F. 1944 Some notes on the performance of high-speed tracked

vehicles

796

7 Micklethwait,

E.W.E.

1944 Soil mechanics in relation to fighting vehicles n/a

8 Skinner, D.R. &

Richardson,

E. M.

1944 The influence of soils on operations involving tracked

and wheeled vehicles

STT 797

9/B Olley, M. 1944 Notes on field testing of A.F.V.s – instrumentation 798

10/A 1944 S.T.T. Interim Report on research into resistance to slip

using subscale model tracks

STT 799

11/A Babbitt, H.E. 1944 The flow of mud and sludge. 800

12/A 1944 Report on the work of the Beach Recovery Committee.

Prepared by ME.6. (b).

ME6 801

13 1944 M.E.6. drawings of shoes and grousers used in recovery

work

ME6 n/a

14/B Hoad, C.W. 1944 Proposal for a full scale rig 802

15 1944 Suspension and track data 803

16 Hoad, C.W. 1944 Mud crossing. short, medium and long term objectives 804

17/B 1944 Scheme drawing of proposed one-third scale rig based

on T.16 Carrier

805

18 Hoad, C.W. 1944 Scale and equipment for laboratory tests 806

19 1944 Extract from G.H.Q. India Liaison Letter No. 8 807

20 Markwick,

A.H.D.

1944 Dimensional analysis of the bearing capacity of soils

under tracked vehicles and its application to tests

with models (Replaced by MC 43)

RRL 808

(Continued)

D. A. GREENWOOD180



Appendix 1. Continued


known)


WO 194/

21 1944 Letter on track and suspension design from C.M.H.Q. to

D.T.D.

DTD 809

22/A 1944 Soil analyses from Skern Beach carried out by R.R.L. RRL 810

23 1944 Summary of the work of Sub-Committee B 811

24 1944 Interim Report of Soils Sub-Committee Recce Party.

Skern Bank, Horsey Island and Poole Harbour

AORG 812

25 1944 Clay and silt areas suggested for reconnaissance ISTD 813

26 Schilling, R. 1944 Report on bogging and gradient performance of various

AFVs. Letter to M. Olley regarding report by E.W.E.

Micklethwait.

814

27 Hoad, C.W. 1944 Observations on paper MC 26 CMCP 815

28 Ward, E. 1944 Mud Crossing Committee: Programme of Investigation FVPE 816

29 Skinner, D.R. 1944 Short term programme 817

30 Minikin, R.R. 1944 Practical considerations on the bearing capacity of

ground

818

31 Skinner, D.R. &

Richardson,

E.M.

1944 The influence of soils on operations involving tracked

and wheeled vehicles (MC 8 re-printed August 1944)

STT n/a

32 1944 Superseded by MC 40 819

33 1944 Bog crossing, Churchill tests, standard suspension and

alternate bogies removed (F.V.P.E. Report No.

FT.1332)

FVPE 820

34 1944 Hill climbing, gravel and grass, Churchill tests, standard

suspension and alternate bogies removed (F.V.P.E.

Report No. FT.1332/1)

FVPE 821

35 1944 A simplified approach to the problem of improving the

performance of tracked vehicles on mud

RRL 822

36 1944 Track Data Table: comparisons between 12 AFVS CMCP 823

37 1944 Report of Soils Sub-Committee Recce Party. Humber

Estuary.Note: This report is listed in the Committee’s

own records (see MC 106) as ‘Report of Soils

Sub-Committee Recce Party. Report on Grangemouth

area of the Firth of Forth and Welsh Banks in the

Severn Estuary.’ The copy lodged as WO 194/824 is

identical with WO 194/831 (MC 45)

AORG 824

38 1944 Draft of First Interim Report by The Committee on Mud

Crossing Performance of Tracked A.F.V.s

CMCP 825

39 1944 Extract from A.F.V.(T) Report No. 1 S.E.A.C. on G.I.P.

Railway Instrument for measuring ground pressure

826

40 1944 Proposed tests to investigate methods of improving the

mud-crossing performance of existing vehicles by

modifications applicable on a short term basis

827

41A 1944 Aerial Recce Report of Soil Sub-Committee Recce

Party

AORG 828

42 1944 Committee on Mud-Crossing Performance of Track

Laying Armoured Fighting Vehicles (First Interim

Report)

CMCP 829

43 1944 Dimensional analysis of the bearing capacity of soils

under tracked vehicles and its application to model

tests

RRL n/a

44 1944 Extracts from BAS/BSM Situation Report No. 27 830

(Continued)






known)


WO 194/

45A 1944 Report of Soils Sub-Committee Recce Party. Humber

Estuary.

AORG 831

46 1944 Interim Report of the Committee, November 1944

(superseding MC 38 and 42)

832

47 Parkinson, D.J.

& Miller,

E.R.Y.

1944 Tank Mobility – I. A method of estimating the

trafficability of soils for tanks

AORG 833

48 1944 A.O.R.G. Report No. 243 – Relation between moisture

content and tank-going

AORG 834

49A 1944 Appendix to Report of Soils Sub-Committee Recce

Party dated 13 Nov. 44 [¼MC 45]. Humber Estuary.

Results of test samples

AORG 835

50 1944 Ministry of Works plan for Soil Bath and Equipment at

FVPE Chertsey

FVPE 836

51 1944 Report of Soils Sub-Committee Recce Party of 19

Areas. Morecambe Bay, Solway Firth, Kirkcudbright,

Wigtown, Ribble Estuary, Mersey Estuary and Dee

Estuary

AORG 837

52 1944 Report of Soils Sub-Committee B. Recce Party:

Brancaster Area

AORG 838

53 Olley, M. 1944 Memo. Mud Crossing Performance. OY. 7/R/

December 1st 1944.

839

54B Grinstead, C.E.

et al.

1944 An improved indicator for measuring static and dynamic

pressures (Reprinted from S.A.E. Journal, November

1944; quoted by Olley in MC 53)

840

55B 1944 Strain gauge illustrations from Baldwin Southwark

Bulletin (quoted by Olley in MC 53)

n/a

56 1944 Studebaker Report on Light Cargo Carrier Re-design

and Development – quoted in MC 2 and MC 53

(Copies of MC 56 on loan from Secretary, Mud

Committee)

n/a

57A 1945 A.O.R.G. Memo. 457 – Description of mobile

laboratory

AORG 841

58A 1945 Report on Soils Sub-Committee Recce Party:

Reconnaissance of Shoeburyness and Foulness

AORG 842

59A 1945 Report on Soils Sub-Committee Recce Party: Isle of

Sheppey, Ham Marshes, Graveney Marshes and The

Oaze

AORG 843

60 1945 An exploration of load distribution beneath track-laying

vehicles. I. Preliminary Tests with Crusader and

Churchill Tanks

RRL 844

61 Ward, E.M. &

Morrogh,

W.F.

1944 Field Trials Report on comparative trials of various

A.F.V’s. in soft ground conditions

FVPE 845

62A 1945 Interim Report of Soils Sub-Committee Reconnaissance

Party. Covering activities up to 12 January 1945

AORG 846

63 1944 Extended end connectors for light tank: Milford tests

(drawbar pull). Extract from B.A.S.(A.F.V.)

Technical Situation Report No. 28.

847

64 1944 Extract from B.A.S.(A.F.V.) Technical Situation Report

No. 29

848

65 1944 Test Plan superseded by MC 72 and MC 82 n/a

(Continued)

D. A. GREENWOOD182





known)


WO 194/

66 Ward, E.M. &

Gould, V.G.

1945 Committee on the Mud Crossing Performance of

Track-Laying A.F.V’s (U.S. War Department Report

900 – ‘Methods of Passing Vehicles over areas

similar in character to Rice Paddy Fields’)

CMCP 849

67 1945 Extract from B.A.S. (R.A.C.) Technical Situation

Report No. 30

850

68 1944 Reprint of Section 1 of U.S. War Dept. Pamphlet

No. 25–1 Equipment for traversing muddy terrain

(Nov. 1944)

n/a

69 1945 Draft Soil Report (in connection with item 3 of the

Agenda for the Meeting March 6th 1945).

Superseded by MC 87

n/a

70 Gordon-Hall,

C.W.,

Skinner, D.R.

& Markwick,

A.H.D.

1945 Report of Track Trials carried out in Italy 11th–24th

December 1944. Also Soil Analysis Report by Road

Research Laboratory on the soils of the above trials

CMCP 851

71 1945 Extracts from minutes: SAE War Tracks Emergency

Committee, Aberdeen, USA

852

72 1945 F.V.P.E. Report No. F.T.1553/2 (Somerset Trials) FVPE 853

73 Macey, H.H. 1945 Some consideration of the mud crossing performance of

tracked vehicles in the light of the plastic behaviour

of clays

BRRA 854

74 Giles, C.G. 1945 Load distribution beneath track laying vehicles: D4 and

D8 caterpillar tractors (R.R.L. Report 438 CGG)

RRL 855

75 Giles, C.G. 1945 Load distribution beneath track laying vehicles:

measurements with a Sherman tank (R.R.L. Report

439 CGG)

RRL 856

76 1945 Italy Trials, 2nd March 1945 857

77 1945 Extract from Situation Report No. 31 l 858

78 Olley, M. 1945 Report OY I/R.Feb.24.’45 commenting on MC 47 and

48 and other matters, including a sinkage recorder

859

79 1945 The recording of sinkage and angular movement of

track links of A.F.V.I. Preliminary records on

Churchill and Sherman Tanks

860

80 1945 Extract from Aberdeen proving Ground: first report on

ordnance program no 5688

861

81 1946–

1947

Report on visit to U.S.A. 862

82 1945 F.V.P.E. Report on 1553/3 (Somerset Trials) Pt.II (Final) FVPE n/a

83 Micklethwait,

E.W.E.

1945 Review of instrumentation in relation to future

programme

863

84 1945 Superseded by MC 90 864

85 1945 Preliminary consideration of mobile rig and equipment 865

86 1945 Appendix ‘A’ to A.F.V. Extract from Mediterranean

area Technical Report No. 27 (summary of soil

investigation in Italy)

866

87 1945 Instructions for completing AFV mud mobility incident

report. Mud Mobility Report (Parts O.I, II & III)

867

88 1945 An exploration of load distribution beneath track-laying

vehicles IV. Measurements with girder track (R.R.L.

Report 448/DGG. May 1945)

RRL 868

(Continued)






known)


WO 194/

89 1945 A.O.R.G. memorandum No. 533. A method for

estimating ‘tank going’ using a towed wheel

AORG 869

90 1945 Notes on ‘rolling resistance’ of tracked vehicles

(Transmission Branch Report No. 88/1 16.6.45)

870

91 1945 An appreciation of various laboratory methods of

investigating A.F.V. track link performance on mud

(R.R.L. Report MOS/452 H.W.W.P. June, 1945)

RRL 871

92 1945 Test procedure for Auburn soil bins and field testing.

Extract from Progress Report No. 3 of the (U.S.)

S.A.E.-T W.E.C. May 1945)

872

93 1945 The classification of soils for military purposes CMCP 873

94 1945 Tank Mobility III. A theory of tank sinkage (A.O.R.G.

Report No. 253 29.5.45)

AORG n/a

95 1945 Mud crossing of A.F.V.s – Ordnance Paper V –A-1, on

shear strength of plastic soils

CMCP 874

96 1945 Some preliminary trials with A.O.R.G. vane machine

(A.O.R.G. Memorandum No. 540)

AORG n/a

97 1945 Some experiments with the Machine Beach Test Mk.III

(Modified) (A.O.R.G. Memorandum No. 579

(26.7.45)

AORG n/a

98 Lewis, W.A. 1945 Static tests on resistance to slip of model track links

with inclined spuds embedded in soft clay (R.R.L.

Report M.O.S./463/W.A.L. July, 1945)

RRL 875

99 Lewis, W.A. 1945 The recording of sinkage and angular movement of

track links of A.F.V.II. Detailed analysis of report on

Cromwell, Churchill and Panther tanks (R.R.L.

Report M.O.S./466/W.A.L. August 1945)

RRL 876

100 1944 Committee on the Mud Crossing Performance of Track

Laying A.F.V.s. Interim Report. [Reprint of MC 42]

Note: This report is listed in the Committee’s own

records (see MC 106) as ‘The development of a

technique for handling soft clay for use in an A.F.V.

soil test bath, by W.A. Lewis’

CMCP 877

101 1945 Tank mobility IV. A theory of tank sinkage, extended to

cover non-homogenous soils (A.O.R.G Report

No. 294)

AORG n/a

102 1945 Report of Soils Sub-Committee Recce Party: Thames

Estuary, East Anglia excluding The Wash, The Wash,

Humber, N.E. Coast, Lancashire and Solway [Firth],

Lakes, Wales and Border Country

AORG 878

103 1945 Report on visit to N.W. Europe to study the soil

conditions critical to tank mobility

n/a

104 1945 Report on visit to Germany, by B.I.O.S. Team No.1172,

to study German soft-ground crossing research and

development; suspension development and

miscellaneous aspects of A.F.V. design

879

105 Giles, C.G. 1945 An exploration of load distribution beneath track-laying

vehicles (V) Measurements with a number of

different types of A.F.V. (R.R.L. report No. M.O.S./

471/cgg. October 1945)

880

(Continued)

D. A. GREENWOOD184





known)


WO 194/

106 1945 Committee on the Mud Crossing Performance of

Track-Laying Armoured Fighting Vehicles. Second

Interim Report

CMCP 881

107 1945 Soils Sub-Committee Recce Report on Soil Analogues.

[Inland Sites]

ISTD 882

108 1945 The bearing properties of liquid muds: some work

carried out in India

900

109 1946 Preliminary report on investigation of Swiss study of

snow mechanics

901

110 Hoad, C.W. 1946 An outline of research in connection with soft-ground

crossing by track-laying AFVs

FVDD 902

111 Hoad, C.W. 1946 Ground testing, soil classification and vehicle mobility

prediction

FVDD 903

Key to source organizations (col. 5): AORG, Army Operational Research Group; BRRA, British Refractories Research Association;CMCP, Mud Committee; DTD, Department of Tank Design; FVPE, Fighting Vehicle Proving Establishment; FVDD, FightingVehicle Design Department; ISTD, Inter-Service Topographical Department; ME6, War Office Department Military Engineering (6);MS, Ministry of Supply; RRL, Road Research Laboratory; STT, School of Tank Technology.Source: MC 106 in WO 194/881 and Catalogue of the National Archives. Note: there are many minor variations in report titles as listed invarious sources and on the face of the actual reports. Final column provides National Archive calalogue file reference numbers, all withinWar Office series code 194. n/a, not available. Copies of these reports have not been lodged with the National Archives.

The author would like to thank the family of the late Pro-fessor J. F. Kirkaldy for access to his Service Record and todocuments that provided a lead to his involvement withthe Mud Committee. I am also grateful to staff at theNational Archives (Kew) for their excellent photocopyingservice and for providing confirmation when docu-ments were missing. Thanks are also due to WendyCawthorne, Assistant Librarian of the Geological Societyof London, for tracking down the non-geologicalpapers published by Kirkaldy in the early postwar periodand to Steve Jebson, Library Information Officer at theMeteorological Office Library (Exeter), and to MalcolmWalker of the History Group of the Royal MeteorologicalSociety, for help with the records of the activities of theMeteorological Office during World War II. Thanks arealso due to J.A. Catt and J.D. Priddy for their helpfulcomments and to E.P.F. Rose for his help with editorialmatters and continued advice and encouragement duringthis research.

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soil and water: research by the british army's committee on mud crossing performance of tracked...

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