Ice Classification of Large Vessels Kaj Riska

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Myles Logan
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1 Ice Classification of Large Vessels Kaj Riska Courtesy of Saint- -Petersburg Maritime Port Administration WHAT IS A LARGE VESSEL IN ICE CONTEXT? Beam larger than the icebreaker beam, B>28 m Ships with large inertia also ship speed influences the concept of largeness Hull shape and propulsion designed for economy in open water Production aspects (frame spacings, framing arrangement, ) Courtesy of SMA

WHAT PARTS IN THE FINNISH-SWEDISH ICE CLASS RULES HAVE BEEN FOUND DIFFICULT: The power requirement increases much for larger vessels The frame spacing limitation for longitudinal

protection required leads to gigantic ice knifes when the difference between LWL and BWL is large The stem area requirement leads to large strengthening with cylindrical bows The

2 WHAT PARTS IN THE FINNISH-SWEDISH ICE CLASS RULES HAVE BEEN FOUND DIFFICULT: The power requirement increases much for larger vessels The frame spacing limitation for longitudinal frames has been claimed to be impossible to follow if welding automats are used The brackets required on longitudinal frames increase much the number of steel parts The rudder protection required leads to gigantic ice knifes when the difference between LWL and BWL is large The stem area requirement leads to large strengthening with cylindrical bows The power delivered by slow speed engines with a FPP in ice is not the maximum power available Courtesy of SMA Escort operations with large vessels require two icebreakers Courtesy of AARI

3 WHERE ARE ICE STRENGTHENED LARGE VESSELS NEEDED? Mainly in hydrocarbon export from Russia in competion/cooperation with pipelines Primorsk m bpd White Sea Varandey Yamal Dikson Sahalin 21.3m bpd Port of Vysotsk Port of Sillamäe winter 25 Port of Primorsk Courtesy of Saint- -Petersburg Maritime Port Administration

1 5x1 3 1x1 3 15x1 3 2x1 3 Displacement [t] IA IA Super Courtesy

4 INFLUENCE OF SCALE IN ICE RULES Finnish-Swedish Ice Class Rules 22 Required power depends on ship size as P 4 Required Power [kw] x1 3 1x1 3 15x1 3 2x1 3 Displacement [t] IA IA Super Courtesy of SMA Finnish-Swedish Ice Class Rules 22 Jacobsen 25 Courtesy of SMA

P Dcalc req /P Dmeas, R CHcalc req /R CHmeas Finnish-Swedish Ice Class Rules 22 Validation situation with full scale and model scale tests 3, 2,5 2, 1,5 1,,5 Brash ice resistance Power, Full scale

5 P Dcalc req /P Dmeas, R CHcalc req /R CHmeas Finnish-Swedish Ice Class Rules 22 Validation situation with full scale and model scale tests 3, 2,5 2, 1,5 1,,5 Brash ice resistance Power, Full scale Resistance, Full scale Power, Model scale Resistance, Model scale The calculation is done using the measured channel thickness, ship speed and measured coefficient of friction., B [m] Finnish-Swedish Ice Class Rules 22 The ship scantlings depend on the scale factor k = P Origin of this is in 1979 ice rules and an ice damage survey 3/ 4 Ice class IA

Finnish-Swedish Ice Class Rules 22 2 18 16 mitattu Measured maksimi maximum jääluokka Ice

6 Finnish-Swedish Ice Class Rules mitattu Measured maksimi maximum jääluokka Ice class IA 1A Super Super maksimien Average of maxima keskiarvo kuorma (kn/m) k = P = Sisu Kemira Arcturus Kashira Finnish-Swedish Ice Class Rules 22 Does the size influence the loads? Damaged ships (hull damage) Ship visits in winter 23

Finnish-Swedish Ice Class Rules 22 Shell structure design (ice class IA) 6 Power IA 5 Pressure [MPa] 4 3 2 1 5x1 3 1x1 3 15x1 3 2x1 3 Displacement [t] Finnish-Swedish Ice

7 Finnish-Swedish Ice Class Rules 22 Shell structure design (ice class IA) 6 Power IA 5 Pressure [MPa] x1 3 1x1 3 15x1 3 2x1 3 Displacement [t] Finnish-Swedish Ice Class Rules 22 5 Ice class IA 4 Power IA Plate thickness [mm] ,,2,4,6,8 1, Frame Spacing [m] Plate thickness t [mm] s =.5 m 5x1 3 1x1 3 15x1 3 2x1 3 Displacement [t]

8 Finnish-Swedish Ice Class Rules 22 5 Ice class IA Power IA Section Modulus [cm 3 ] ,,2,4,6,8 1, Frame Spacing [m] Section Modulus [cm 3 ] Displacement [t] s =.5 m l = 3.5 m 5x1 3 1x1 3 15x1 3 2x1 3 INFLUENCE OF SCALE IN SOME ICE RULES Russian Maritime Register of Shipping 1999 Ice pressure p ~ 1/6 Propulsion power P D ~ IACS harmonized rules Ice load F ~.64 but a cut off at about =21 t DNV in POLAR or Icebreaker notation Load height h~ 1/2 i.e. F~ 1/2 GL Pressure independent of ship parameters, only a class factor Lloyd s Register, AC classes Ice pressure is only a class factor Propulsion power recommended P D ~B~ 1/3

POINTS OF IMPROVEMENT IN VIEW OF SHIP SIZE: 1. The power requirement is to be adjusted so that the level of required power corresponds to the requirements set by the winter navigation system 2.

9 POINTS OF IMPROVEMENT IN VIEW OF SHIP SIZE: 1. The power requirement is to be adjusted so that the level of required power corresponds to the requirements set by the winter navigation system 2. The influence of ship size on the scantlings is to be investigated 3. The stem area definition is to be made more precise 4. The rudder protection is to be defined more clearly 5. The hull area definitions could be re-considered THESE ARE HEADING FOR LUNCH LET S FOLLOW THEM! THANK YOU FOR YOUR ATTENTION!

VINTERSJÖFARTSFORSKNING. TRAFFIC RESTRICTIONS TO FINNISH AND SWEDISH PORTS Setting the Restrictions based on Ice Thickness and Distance Sailed in Ice

VINTERSJÖFARTSFORSKNING. TRAFFIC RESTRICTIONS TO FINNISH AND SWEDISH PORTS Setting the Restrictions based on Ice Thickness and Distance Sailed in Ice STYRELSEN FÖR VINTERSJÖFARTSFORSKNING WINTER NAVIGATION RESEARCH BOARD Research Report No 58 Patrick Eriksson, Kaj Riska and Jouni Vainio TRAFFIC RESTRICTIONS TO FINNISH AND SWEDISH PORTS Setting the Restrictions