DNV GL © 2014 SAFER, SMARTER, GREENER DNV GL © 2014
ICE CLASSES
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ICE CLASSES in Brief
Håvard Nyseth/Karsten Bertelsen
DNV GL © 2014
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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DNV GL © 2014
EXAMPLE: Weight increase vs stiffening arrangement
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NB! May vary depending on size, bow form, structural configuration etc.
DNV GL © 2014
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
DNV GL © 2014
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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DNV GL © 2014
Design load vs load area
DNV
“Arctic”
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Pressure Plating
Transverse frames
Longitudinals
Length
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Design load vs load area
Pressure
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FSICR Transversely stiffened plating
Transverse frames Longitudinally stiffened plating
Longitudinals
Length
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Design load vs load area
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
DNV GL © 2014
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
DNV GL © 2014
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
Plating and framing (Midship) 0,3 2 54 650 18,00 6,00
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
Plating and framing (Forward) 0,3 2 108 1292 18,00 8,00
ICE-1C/180,000/16,800/77.898/8.000 112 longitud. 3 235 13,3 721 19,058 17,20 7,40
Plating and framing (Midship) 0,6 2 21 247 17,80 6,70
ICE-1C/180,000/16,800/77.898/8.000 112 longitud. 3 235 13,3 941 13,833 17,20 7,40
Plating and framing (Midship) 0,3 2 19 227 17,80 6,70
ICE-1C/180,000/16,800/77.898/8.000 182 longitud. 3 235 13,3 2868 36,013 17,20 7,30
Plating and framing (Forward) 0,6 2 82 982 17,80 6,40
ICE-1C/180,000/16,800/77.898/8.000 182 longitud. 3 235 13,3 3740 25,593 17,20 7,30
Plating and framing (Forward) 0,3 2 75 904 17,80 6,40
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Draughts [m]:
4
5
2
6
7
8
3
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