COMBINING ICE CLASS RULES WITH DIRECT CALCULATIONS FOR DESIGN OF ARCTIC LNG VESSEL PROPULSION

• Main Author: Sing-kwan Lee
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.644.704; http://www.eagle.org/eagleExternalPortalWEB/ShowProperty/BEA Repository/References/Technical Papers/2008/CombiningIce-ClassRules/

Ships navigating in ice areas perform quite differently due to ice resistance as compared to their open sea operations. It is a challenge for ship designers to find a design solution which not only optimizes the propulsion performance in open sea but also provides the ship with good ice performance. Traditionally, many ship designers have used rule formulae in Finnish-Swedish Ice Class Rules (FSICR) to estimate the required engine power. While the use of these formulae have proven to be satisfactory thus far, recently increased growth in the activities in oil and gas production in the Arctic area call into question the continued applicability of these Rules for a very obvious reason. The transportation of these oil and gas products requires ice tankers and ice LNG ships to operate in ice conditions much thicker than those previously assumed in FSICR. In such cases, more and more ship designers are turning to direct calculations and model tests for propulsion designs. In this paper, the two most critical design issues in ice ship propulsion will be discussed, namely engine powering and propulsor performance. Comparisons of propulsion designs based on FSICR and on direct calculation are presented for different propulsors. These include fixed pitch, controllable pitch, and ducted propellers for their performance in ice operation. 1.