Bureau Veritas has published new rules for polar class vessels and production installations, plus specific guidance on ice/structure interaction.
The objective is to help speed up Arctic and Caspian Sea oil and gas development activity by facilitating the building of tank, cargo, and offshore service vessels that can operate unsupported by icebreakers in very heavy ice.
The guidance note also covers floating LNG (liquefied natural gas) and oil platform construction in high Arctic conditions.
Philippe Baumans, development director at the classification body, said BV’s new “Rules for the classification of Polar Class and Icebreaker Ships” brings together for the first time the requirements for icebreakers and oil and gas-related tonnage.
Baumans said: “For extracting oil and gas from the Arctic and also from the very icy and difficult Caspian Sea, there is an increasing demand for vessels which can carry cargo and also ram and break ice unsupported by an icebreaker.
“Under our new Polar Rules that is possible, and the owner can choose an icebreaker class from 1 to 7 for the cargo vessel, tanker or platform supply vessel they need, which will reflect the heaviness of the ice that can be dealt with unsupported.”
BV currently classes a number of offshore vessels specifically for the Caspian Sea, which has very heavy ice characteristics that are complicated by the very shallow waters that characterise the Kazakhstan sector.
“We are considering a specific Caspian notation, as although the ice requirements in the Caspian are similar to the Arctic in some ways, in others they differ.
“Understanding ice loads and structure in detail is vital to that, as it is for the new generation of offshore floater that will be needed for high Arctic fields such as Shtokman.”
BV has also published Guidance Note NI565 Ice Characteristics and Ice/Structure Interactions. The purpose of this guidance note is to collect and provide data on ice characteristics as well as giving some guidance on the calculations of the forces generated by the ice on ships and offshore structures.
It indicates some information on the different types of ice and on their mechanical properties. It gives some analytical formulae and methodologies to estimate the forces applied on the structures due to ice, with respect to the different modes of failure of the ice.
Baumans: “We have done extensive work with St Petersburg University and Aker Arctic on ice loads, much for the Shtokman project and aimed at clarifying the needs for floating LNG platforms and LNG shuttle tankers.
“These guidance notes are a way in which we can share that knowledge with industry.
“We have further refined our IceSTAR ice load calculation software, which we hope to make available to industry next year. We also expect to publish new rules and guidance for using podded propulsion in ice next year.
“That will facilitate the development of double acting tankers and gas carriers. They will break ice stern first and make ocean transits bow first, maximising the hull form efficiency in each environment.”
A number of these vessels have been built in recent years, notably for Neste Oil of Finland.