Servicing the Arctic. Report 2: Evaluation of Damen Concepts in Arctic Conditions: Concepts Survey

Background At the start of a design it is often good to look at comparable designs. What choices were made, what are the operations, what equipment is used? This report looks at three Damen ships, which are already capable of offshore support. These vessels are designed for open water. Looking just at what has to improve for operating in the Arctic will give a feeling for the design of such vessels. The recommendations are taken into account in the next report, where a concept design of an Arctic Offshore Support Vessel will be developed. Results There are two operational profiles per vessel. One is the original operational profile and the other one is about the same operations but then in ice. The operational profiles are used for calculating an indication of fuel consumption. The ships themselves are tested on winterization, resistance, propulsion, construction and stability. This is done according to rules and guidelines available. For the resistance prediction the Lindqvist and Riska formulae are used. Winterization of the ships is very well possible, because the superstructure that is in place is already providing cover. The working and safety areas that are still outside have to be enclosed and the equipment that is on deck will have to be winterized. The resistance of the ships can only be determined with Riska, due to the fact that the bow angles are not intended for icebreaking. This results in a negative crushing component with Lindqvist. A high resistance is the result for the three vessels, leading to a high required propulsion power, around 30 MW. This is rather high compared to similar vessel, Vitus Bering, which requires 13 MW for the same speed and ice thickness. Sailing backwards through the ice could be an option to decrease this power requirement. There are relatively minor adaptions required to do so. Looking at the construction, a ice strengthening has to be applied to the hull. Dependent on the class notation and location around the hull, the steel thickness ranges from 20 - 80 mm. This is considerably thicker than the more common 15 mm. The general layout of the ship gives good stability, and meets any requirement on this subject. Conclusions Optimizing a vessel for the Arctic requires a lot of adaptations. Due to the impact of these adaptations on the entire vessel design, a ship should be specially designed for operating in the Arctic, especially with the higher ice classes such as 1A Super, PC6 and PC 4