Feature 5 | Ice class vessels
Ice experts plan for Arctic oil exploration
Lloyd’s Register is currently involved in developing new technological
approaches aimed at enhancing the performance of ice capable ships. By
Robert Hindley, surveyor, Lloyd’s Register Asia.
W
ith the most significant from an operational envelope definition, with and further pushing up the costs involved.
developments for Arctic shipping input from the designer, prospective operator Until now, in the few instances were hull
in the near future likely to be and other key stakeholders on exactly how monitoring has been deployed on ships in
associated with specific projects, including oil the ship will be operated in defined ice trade, it has been difficult to fully assess
and gas exploration, shuttle tanker operations conditions. the ice conditions in which the ship was
from high Arctic offshore oil fields and As Arctic shipping development continues, operating.
high-grade ore shipments from remote Arctic Lloyd’s Register Asia sees an operational However, the maritime industry has largely
mines, many of the design projects are being scenario based approach to both design and overlooked a rich source of information –
tailored to the shipping requirements and the design review as an effective way of providing what happens when ice loads on a ship’s hull
environmental conditions of the operational confidence in new ships operating in the exceed the ship’s design limits. Because ice
area. Arctic, beyond the scope of application of loads that exceed a ship’s design point can be
In addition to this project-specific work prescriptive ice class rules. evaluated by a review of the damage caused,
however, the class society is also undertaking However, one of the main issues holding such reviews, when compared to full-scale
more general work in support of assessing back research into ship strengthening is a measurements, provide valuable insights
strengthening requirements for ships lack of comprehensive ship-ice-load data, into the response of structure to ice, and at
operating in Arctic waters. correlated to recorded ice conditions. At a comparatively low cost. Also, every ship
Regarding the project-specific work, present, the collection of such data can operating in ice can potentially provide the
Lloyd’s Register Asia has recently undertaken require the installation of equipment such as measurements the industry needs.
a number of pilot applications using an strain gauges on the ships’ hulls – all of which Using recorded damage evidence to
operational scenario-based design approach can be very expensive. improve the industry’s understanding of
in order to refine procedures for design the loads ships experience when operating
review, based on real projects. in ice is not in itself new. In 1968, an
These pilot applications and an overview
“However, the
analysis of damaged ships operating in
of the approach of assessing ice strengthening the Baltic was used to refine the ice-class
using operational scenarios was presented at maritime industry rules of the Finnish and Swedish maritime
the International Conference of Port and
Ocean Engineering under Arctic Conditions
has largely
administrations.
In the paper that Lloyd’s Register Asia
(POAC) in Luleå, Sweden in June 2009.
overlooked a
presented in September 2009, in association
For such bespoke designs, classification with Aker Arctic Technology at the RINA
society ice class rules are typically the rich source of ICSOT 2009: Ice Classed Vessel conference
foundation on which a design may be based.
However, consideration of the specific
information – what
in Busan, South Korea, the authors use
analytical methods and practical approaches
operational and environmental characteristics
happens when ice
to determine the ice pressures related to the
of the project will then be added, often with damage incurred by ships in commercial
the final design differing greatly from a
loads on a ship’s
operation. The results are compared with the
standard ‘rule based’ ship.
hull exceed the
ships’ design and a number of strengthening
However, ice class rule sets that are based levels associated with current ice-class rule
on different operational and simplified design
ship’s design limits.”
requirements.
assumptions may not provide the level of Preliminary results of the study indicate
confidence to the operator needed for the that there is scope for reducing the
specific tasks that the ship must undertake. Moreover, most dedicated ice trials, strengthening levels in some areas of the
To ensure a safe level of design is reached where the ice conditions can be practically hull for specific ship types, reducing the
for such Arctic projects, the class society determined, currently require ships involved steel weight, while maintaining a safe level of
is developing an approach of using an to be withdrawn from commercial service strengthening. However, there also appears
operational scenario based design review. while they carry out the research work. to be a need to re-address the way in which
This involves ensuring that, through a hazard And in conducting such research, it is often some ice-class requirements - notably in
identification and risk mitigation process, the difficult to find the right ice conditions in terms of ice-strengthening extents - are
design requirements for the ship are derived which to test, adding to the ship’s down-time, defined. NA
74 The Naval Architect January 2010
NA Jan 10 - p74.indd 74 12/01/2010 09:54:16
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