ice classes in brief

DNV GL © 2014 SAFER, SMARTER, GREENER DNV GL © 2014

ICE CLASSES

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ICE CLASSES in Brief

Håvard Nyseth/Karsten Bertelsen

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DNV Rules Pt.5 Ch.1 Sec.3 - Baltic ice classes

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DNV Rules Pt.5 Ch.1 Sec.4 - DNV “Arctic” Classes:

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DNV Rules Pt.5 Ch.1 Sec.8 - Polar Classes

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Typical restrictions imposed by Finnish authorities

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Polar Class in Canadian Arctic

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Polar Class in Russian Arctic /Arctic Ocean

Russian Arctic/NSR

It would appear that the minimum polar

class required for independent

navigation along the whole NSR would

be PC2 for year round operation and

PC5 for spring/summer transits

May be dictated by powering and

icebreaking performance rather than by

strength level

Arctic Ocean

It is anticipated that a PC1 and 2 vessel

of adequate power and maneuverability

could transit in polar pack year round

In summer, PC3 would be structurally

adequate to undertake cautious

voyages independently

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Antarctic Ocean

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Ice Class Comparison is not easy……

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EXAMPLE: Weight increase vs stiffening arrangement

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NB! May vary depending on size, bow form, structural configuration etc.

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DNV ICE and POLAR Ice Class

Examples of Vessels and Newbuildings built to ICE or POLAR Ice Class notation

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Idno. Name Status Typical area of operation Ice Class Notation

18620 ERNEST SHACKLETON In Operation Antarctica ICE-05 Icebreaker

22866 POLARBJØRN In Operation Arctic ICE-05 Icebreaker

21779 TOR VIKING II In Operation Baltic ICE-05 Icebreaker

16363 HMS ENDURANCE In Operation Antarctica ICE-05 Icebreaker

19920 BOTNICA In Operation Baltic ICE-10 Icebreaker

26121 PACIFIC ENDEAVOUR In Operation Sakhalin ICE-10 Icebreaker

26122 PACIFIC ENDURANCE In Operation Sakhalin ICE-10 Icebreaker

26123 PACIFIC ENTERPRISE In Operation Sakhalin ICE-10 Icebreaker

25158 FESCO SAKHALIN In Operation Sakhalin ICE-10 Icebreaker

25600 POLAR PEVEK In Operation Sakhalin ICE-10 Icebreaker

21805 VIDAR VIKING In Operation Baltic ICE-10 Icebreaker

21804 BALDER VIKING In Operation Baltic ICE-10 Icebreaker

25884 UMIAK 1 In Operation Canada ICE-15 Bulk Carrier

25414 VLADISLAV STRIZHOV In Operation Barents/Arctic ICE-15 Icebreaker

26073 YURY TOPCHEV In Operation Barents/Arctic ICE-15 Icebreaker

22685 SVALBARD In Operation Barents/Arctic POLAR-10 Icebreaker

17723 FENNICA In Operation Baltic POLAR-10 Icebreaker

17933 NORDICA In Operation Baltic POLAR-10 Icebreaker

15519 ODEN Post Class Baltic/Arctic/Antarctica POLAR-20 Icebreaker

D28089 FRONTIER DRILLING In Operation ICE-05 Ship-shaped drilling unit

Stena DrillMax ICE Pre Class PC6 (PC4 for hull) Ship-shaped DU

STX Rauma Pre Class PC5 /ICE-10

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Ice Class Requirements – High Level Comparison

Polar Class (PC) DNV ”Arctic” FSICR

Load formulation Bow shape Included Not included Not included

Displacement

dependency

Strong dependency Global – yes

Local – no

Moderate dependency

Secondary strength

members

Plate requirement Plastic, includes varying

permanent deformation

Related to plastic capacity

at zero perm. deformation

Related to plastic capacity

incl. margin wrt perm.

deformation

Stiffener requirement -Plastic

-Iterative design

-Shear/section modulus

interaction

-Elastic

- Separate shear and

section modulus

requirements

-Elastic

-Section modulus

requirement. Shear

requirement only for

longitudinal frames

Primary strength

members

Plastic mechanisms not

anticipated.

Safety factor included

Elastic Elastic

Longitudinal strength Head on ramming Head on ramming

(POLAR)

Not applicable

Power requirements No Yes Yes

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Ice-structure interaction philosophy - Rules

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ppeak ppeak

pavg

pavg

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Design condition

Load / Capacity

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Length

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Design load vs load area

DNV

“Arctic”

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Pressure Plating

Transverse frames

Longitudinals

Length

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Pressure

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FSICR Transversely stiffened plating

Transverse frames Longitudinally stiffened plating

Longitudinals

Length

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Polar

Class

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Length

Pressure

Longitudinally stiffened plates Longitudinals

Transversely stiffened plates Transverse frames

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Baltic ice classes - extent of ice strengthening

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Aft Region

Midship Region

Forward Region

Requirements to: • Plating and stiffeners in

icebelt • Girders and stringers in

icebelt • Appendages • Machinery components

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Design conditions for Baltic ice classes

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Design condition for ice strengthening is given in Table A1, and refers to operation in open sea conditions corresponding to a level ice thickness not exceeding h0 in Table B1. The design height (h) is however assumed to be a fraction of the level ice thickness. Design condition for propulsion is a minimum speed of 5 knots in brash ice channels, as given in Table J4 1) 1) Ships having the propulsion power determined by model tests, additional approval by FMA or SMA is necessary for ships requesting Finnish ice certificate

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Example calculation

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INPUT

Main Data:

L. betw. perp. Lpp: 180,000 m

Rule length L: 180,000 m AP Amidsh. FP

Breadth moulded B: 32,200 m UIWL: 16,800 16,800 16,800

Draught moulded T: 16,800 m LIWL: 8,000 8,000 8,000

Block coefficient Cb: 0,800 m

Ice Displ.: D f = 77.898 tonnes UIWL LIWL

Max engine outp. PS = 8.000 kW "LPP" [m]: 180,000 180

Service speed V = 15,00 knots x aft [m]: 35,000 40,000

x fwd [m]: 145,000 140,000

Add. data for calc. of minimum required Engine output: UIWL LIWL UIWL LIWL

Number of propellers Max. breadth at WL: B : 32,200 32,200 m Waterl. angle at B/4: a : 30,0 30,0 degrees

Propeller diam., Dp = m Length of bow LBOW : 35,000 40,000 Rake of stem at CL: f1 : 90,0 90,0 degrees

Propeller type: L. of par. midship LPAR : 110,000 100,000 Rake of bow at B/4: f2 : 60,0 60,0 degrees

Bulbous bow fitted: Area of w.l. of bow: Awf : m2 Req. engine output, Ps : #N/A #N/A kW

The T, Awf/LB, Awf/LB Parameters for calculating min engine output are outside valid range, see Rules

RESULTS

Span sF m ls Af p t/F Hpl HpbNo Location Ice strengthening Frame Type [m] [N/mm2] [m] [cm2] [kN/m2] [*] [m] [m]

Id. text item no. Spacing tc b lf/hs Aw A Z Hfl Hfb

[m] [mm] [m] [m] [cm2] [cm2] [cm3] [m] [m]

ICE-1A*/180,000/16,800/77.898/8.000/15,00 112 longitud. 3 235 13,3 1443 29,665 17,40 6,80

Plating and framing (Midship) 0,6 2 62 749 18,00 6,00

ICE-1A*/180,000/16,800/77.898/8.000/15,00 112 longitud. 3 235 13,3 1881 20,538 17,40 6,80


ICE-1A*/180,000/16,800/77.898/8.000/15,00 182 longitud. 3 235 13,3 2868 41,006 17,40 6,80

Plating and framing (Forward) 0,6 2 124 1489 18,00 8,00

ICE-1A*/180,000/16,800/77.898/8.000/15,00 182 longitud. 3 235 13,3 3740 28,137 17,40 6,80


ICE-1C/180,000/16,800/77.898/8.000 112 longitud. 3 235 13,3 721 19,058 17,20 7,40


ICE-1C/180,000/16,800/77.898/8.000 112 longitud. 3 235 13,3 941 13,833 17,20 7,40


ICE-1C/180,000/16,800/77.898/8.000 182 longitud. 3 235 13,3 2868 36,013 17,20 7,30


ICE-1C/180,000/16,800/77.898/8.000 182 longitud. 3 235 13,3 3740 25,593 17,20 7,30


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Draughts [m]:

4

5

2

6

7

8

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