Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Ensuring of the strength of large Arctic LNG carriers and oil tankers for year-round transportation in the Arcticconditions
A. Andryushin, P. Zuev, A. Voronin, S. Fedoseev, S. Ryabushkin
Laboratory of propulsion complexes of ships, Central Marine Research and Design InstituteSaint-Petersburg, Russia
M. Kuteinikov
Hull department, Russian Maritime Register of Shipping, Saint-Petersburg, Russia

that there are not enough Arctic icebreakers available while the numberof merchant vessels that need assistance is growing. In this caseicebreaker assistance is carried out under the most severe ice conditionsof the route. The areas of light ice conditions are overcome by ice
vessels independently. Taking the latter into account, development andoperation of large double-acting cargo ships of improved ice
performance is a typical trend of modern Arctic shipping. Table 1
below submits the main characteristics of the large-capacity Yamal
max Arctic LNGC (“Christophe de Margerie”) and the prospective
LNGC intended for year-round LNG transportation to the East. (Glebkoet al, 2017; Shtrek, 2019; Tsoy et al, 2013; Tsoy et al, 2012). TheseLNGCs are double acting ships (DAS). Ice strengthening corresponds
to Arc7 and Arc8 classes according to the requirements of the Russian
Maritime Register of Shipping (RS). The characteristics of theprospective LNGC go beyond the previous design and operating
experience. Astern level ice capability of these ships exceeds 2 m thick,this is comparable with Arctic icebreakers of “Arktika” type (project1052, shaft power 49MW). Improved ice performance should guarantee
passage of a ship under severe ice conditions of the Eastern sector of
the NSR at speeds that ensure efficiency of cargo transportation. Highpower and icebreaking capability, increased average speed of theprospective LNGCs under severe ice conditions lead to an increase in
ice loads which should be taken into account for strength assurance andIce class assignment correspondingly. The ability to operate in thespecified ice areas is determined depending on a navigation period,current weather conditions, current ice conditions, availability oficebreaker assistance and is the responsibility of the ship-owner (RS,Circular letter 312-11-1662c of 20.12.2021). This requires anapplication of appropriate design proposals to ensure sufficient ice
strength and safe operation. The solution of the above problems
involves consideration of the direct methods to assign ice loads and hullstrengthening on large-capacity Arctic ships in order to ensure theirsafe and efficient year-round operation along the NSR including theEastern sector.

ABSTRACT
Ensuring of year-round export of hydrocarbons and other cargoes
through the Eastern sector of The Northern Sea Route (NSR) is one of
the urgent tasks of modern Arctic shipping. The implementation ofsuch projects necessitates using large-capacity icebreaking gas carriers(LNG) and tankers of high Arctic сlasses. Ensuring of hull strength ofsuch ships is one of the knotty problems of their design.
The operating modes, main dimensions and hull lines of the prospective
large-capacity icebreaking vessels including DAS (double acting ship)
go beyond the previous design and operation experience. It induces theneed of development of refined methods to ensure hull ice strength. The
article discusses the typical features of operation of large-capacity
Arctic vessels. The analysis of morphological and strengthcharacteristics of ice formations is carried out depending on anavigation period. Direct methods of assigning ice loads to a hull andensuring its strength during design and operation are presented. Basedon the analysis performed and the NSR requirements (The Rules ofNavigation in the waters of the Northern Sea Route, 2020), it wasindicated that for efficient eastbound year-round transportation of LNG
along the NSR to South Asia, it is advisable to use double-acting
LNGC Arc8 сlass with improved ice characteristics in comparison withLNGCs of “Christophe de Margerie” type Arc7 сlass.

KEY WORDS: ICE LOADS; ICE CONDITIONS,ICEBREAKERS, ICE GOING VESSELS, ICE PROPERTIES,HULL STRENGTH, OPERATING MODES, SAFE SPEED,RIDGES, LEVEL ICE.
SETTING UP AN ISSUE
The time being is characterized by intensive cargo transportation along
the NSR. Hydrocarbons are general cargo to be transported. The
Novotek’s project for year-round export of LNG to South Asia along
the NSR is at the stage of implementation. Year-round container
shipping is also planned. Traffic volume may amount to 80 million tonsby 2030. Prospective volume of the Novotek’s LNG delivery is up to40 million tons. Effective cargo turnaround of the above volumes
necessitates using large-capacity transport ships (LNGCs, tankers) ofhigh Arctic сlasses. Sufficient traditional icebreaker assistance(operation in a channel behind an icebreaker) is complicated by the fact1391