free board

TYPE-’A’ SHIPTYPE-’A’ SHIP

LIQUID CARGOES ONLYLIQUID CARGOES ONLY

CARGO TANKS LOW PERMEABILITYCARGO TANKS LOW PERMEABILITY

SMALL DECK OPENINGS, WATERTIGHT STEEL COVERSSMALL DECK OPENINGS, WATERTIGHT STEEL COVERS

HIGH DEGREE OF SUB-DIVISIONHIGH DEGREE OF SUB-DIVISION

IF +150m MUST REMAIN AFLOAT AFTER FLOODING OF IF +150m MUST REMAIN AFLOAT AFTER FLOODING OF ANY SINGLE EMPTY COMPART’tANY SINGLE EMPTY COMPART’t

TYPE-’B’ SHIPTYPE-’B’ SHIP

ANY SHIP WHICH IS NOT A TYPE ‘A’ SHIPANY SHIP WHICH IS NOT A TYPE ‘A’ SHIP

HAS A GREATER FREEBOARD THAN TYPE ‘A’ SHIPHAS A GREATER FREEBOARD THAN TYPE ‘A’ SHIP

LESSER DEGREE OF SUB-DIVISIONLESSER DEGREE OF SUB-DIVISION

VULNERABLE IN HEAVY WEATHER TO FLOODINGVULNERABLE IN HEAVY WEATHER TO FLOODING

LARGE DECK OPENINGSLARGE DECK OPENINGS

TYPE- ‘B-60’ SHIPTYPE- ‘B-60’ SHIP

ANY TYPE ‘B’ SHIP OVER 100 m LONGANY TYPE ‘B’ SHIP OVER 100 m LONG

STEEL HATCH COVERS WEATHERTIGHTSTEEL HATCH COVERS WEATHERTIGHT

REMAIN AFLOAT AFTER FLOODING OF SINGLE REMAIN AFLOAT AFTER FLOODING OF SINGLE COMPARTMENT ( COMPARTMENT ( = 95% ) AT SUMMER DRAFT = 95% ) AT SUMMER DRAFT

FREEBOARD REDUCED BY 60% OF TABULAR ‘A’ ~ ‘B’FREEBOARD REDUCED BY 60% OF TABULAR ‘A’ ~ ‘B’

TYPE- ‘B-100’ SHIPTYPE- ‘B-100’ SHIP

ANY TYPE ‘B-60’ SHIP OVER 100 m LONGANY TYPE ‘B-60’ SHIP OVER 100 m LONG

STEEL HATCH COVERS WATERTIGHTSTEEL HATCH COVERS WATERTIGHT

ACCESS TO E.R. FROM DECK PROTECTED BY HOUSEACCESS TO E.R. FROM DECK PROTECTED BY HOUSE

OPEN RAILS NOT BULWARKS FOR 50%LOPEN RAILS NOT BULWARKS FOR 50%L

CREW ACCESS BY GANGWAY OR UNDER DECK PASSAGECREW ACCESS BY GANGWAY OR UNDER DECK PASSAGE

REMAIN AFLOAT AFTER FLOODING OF ANY TWO FORE & AFT ADJACENT REMAIN AFLOAT AFTER FLOODING OF ANY TWO FORE & AFT ADJACENT COMPARTMENTS ( COMPARTMENTS ( = 95% ) AT SUMMER DRAFT = 95% ) AT SUMMER DRAFT

FREEBOARD REDUCED BY 100% OF TABULAR ‘A’ ~ ‘B’FREEBOARD REDUCED BY 100% OF TABULAR ‘A’ ~ ‘B’

STATE OF EQUILIBRIUMSTATE OF EQUILIBRIUMFinal waterline MUST BE below any opening that Final waterline MUST BE below any opening that allows ‘progressive’ floodingallows ‘progressive’ flooding

Final GM at least 0.05m.Final GM at least 0.05m.

Max. GZ not less than 0.1m.Max. GZ not less than 0.1m.

Final angle of heel 15Final angle of heel 15 or less or less

Positive range at least 20Positive range at least 20

Ships over 150m in length - E.R. is classed as Ships over 150m in length - E.R. is classed as floodable compartment ( floodable compartment ( as 85% ) as 85% )

TABLE-’A’ TABLE-’B’

LENGTH F’BOARD

100m 1180 mm

110m 1240 mm

120m 1263 mm

130m 1299 mm

140m 1355 mm

150m 1379 mm

160m 1423 mm

170m 1569 mm

180m 1642 mm

LENGTH F’BOARD

100m 1380 mm

110m 1440 mm

120m 1463 mm

130m 1499 mm

140m 1555 mm

150m 1579 mm

160m 1628 mm

170m 1770 mm

180m 1850 mm

FREEBOARD ASSIGNMENT

1. TABULAR FREEBOARD FROM TABLE ‘A’ OR ‘B’a) B-60 / B-100 correction

b) Wooden Hatch correction

c) Flush Deck correction ( ≤ 100m in length )

d) Block Coefficient correction ( Cb > 68% )

2. BASIC FREEBOARDa) Depth correction

b) Deck line position

c) Superstructure / Trunk correction

d) Sheer correction

e) Bow height correction

3. SUMMER FREEBOARDa) Owners request ( increase only )

b) Other increase ( cargo doors / ports below F’board deck )

4. ASSIGNED FREEBOARD

WOODEN HATCH CORRECTION

TABULAR F’BOARD INCREASED if in ‘POSITION-1’

( POSITION-1 = ALL OF F’BOARD DECK, + 25% OF SUPERSTRUCTURE DECK )

FLUSH DECK CORRECTION

TABULAR F’BOARD INCREASED FOR TYPE-B SHIPS

IF ≤ 100m IN LENGTH AND

SUPERSTRUCTURE IS ≤ 35% OF SHIPS LENGTH

E.G. SHIPS LENGTH = 100m, SUPERSTRUCTURE = 35m

BLOCK COEFFICIENT CORRECTION

FREEBOARD INCREASED IF Cb = > 0.68 WHEN MEASURED

AT 85% OF SUMMER DRAFT

F’BOARD IS MULTIPLIED BY ( 0.68 + Cb ) ÷ 1.36

MOULDED DEPTH

85% OF MOULDED DEPTH

DEPTH CORRECTION

STANDARD DEPTH FOR FREEBOARD RULES = L ÷ 15

IF DEPTH MEASURED = MORE THAN L ÷ 15

FREEBOARD IS INCREASED

DEPTH CORRECTION

STANDARD DEPTH FOR FREEBOARD RULES = L ÷ 15

IF DEPTH MEASURED = LESS THAN L ÷ 15

FREEBOARD IS REDUCED, IF:

SUPERSTRUCTURE = 60% L AMIDSHIPS POSITION, OR

CONTINUOUS TRUNK FULL LENGTH

DECK LINE POSTION CORRECTION

FREEBOARD MUST BE CAPABLE OF VERTICAL MEASUREMENT

IF SHIP HAS ROUNDED GUNWHALE,

DECK LINE IS LOWERED THUS:

Corrected freeboard

SUPERSTRUCTURE CORRECTION

SHIPS WITH SUFFICIENT “STANDARD HEIGHT” SUPERSTRUCTURE, OR

SUFFICENT WATERTIGHT TRUNKING

FREEBOARD WILL BE REDUCED

SUPERSTRUCTURE CORRECTION

IF SUPERSTRUCTURE / TRUNKING IS NOT SUFFICIENT IN HEIGHT / %AGE L / OR WIDTH,

NO REDUCTION IN FREEBOARD

SHEER CORRECTION

GREATER THAN STANDARD SHEER

FREEBOARD IS REDUCED

SHEER CORRECTION

LESS THAN STANDARD SHEER

FREEBOARD IS INCREASED

NO REDUCTION FOR SHEER IF:

LESS THAN 20% L SUPERSTRUCTURE AMIDSHIPS

CORRECTION FOR ‘BOW HEIGHT’

MINIMUM BOW HEIGHT IS CALCULATED BY FORMULA

FORMULA IS DEPENDENT ON L AND Cb

IF THE BOW IS LESS THAN CALCULATED HEIGHT

FREEBOARD IS INCREASED