NOVEMBER 27, 2019
By G Torneman, AB Volvo Penta, Sweden
For wind farm workboat operations, various designs of vessels and propulsion system are used for different kind of missions, such as crew transfer, material transport, fuelling, survey and security handling. Vessels can be of SWATH design, catamaran design with symmetrical or asymmetrical hulls, mono hulls and trimarans. Propulsion systems used today are waterjet propulsion system (WJ), Controllable Pitch Propeller systems (CPP), Fixed Pitch Propellers (FPP) and Podded system (IPS). This paper will mainly cover the use of podded systems in comparison to WJ systems and FPP in catamaran applications. It’s based on discussions with wind farm service providers and skippers as well as Volvo Pentas own experience in the field. Any statements should be seen as opinions solely from the author, but could sometime be based on real case studies.
In case you would like to receive more information or discuss about this subject, please contact Jeffrey Bowles.
Volvo Penta IPS propulsion systems with forward facing contra rotating propellers have proven themself to be very successful in WFSV Wind Farm Support Vessels in the 16-19 m range. The high fuel efficiency during high speed transfer from shore to offshore site, the manoeuvrability advantages with active rudders and the high zero speed thrust with controlled exhaust temperatures has helped the operators and the vessels helmsmen to fulfil their missions of transferring crew, technicians, service engineers and fuel out to the wind farm locations in the roughest weather conditions. Now, when the operators are designing and building vessels for the new fields with much longer distances to go from nearest harbour, the multi-engine lay out with 4 engines has been recognized as one of the best concept to ensure high redundancy for the vessel operations and minimize the risk of costly down times for the wind farm operators. With Volvo Penta Quadruple IPS installation all the features of the IPS system, including active manoeuvring in high seas, no risk of losing grip in water in bollard push against the wind farm pylon and reduced fuel consumption compared with fixed pitch propellers and waterjets, are available for the 24-30 m range of WFSV. The paper will show the calculations of speed and thrust for different vessels type as well as different lay-outs of the IPS system in a multiple engine application. Experience from WFSV operation with Volvo Pentas engines and prop system will also be presented with load factors and experience from real duties.
Photos of NOS Northern Offshore Services are taken from www.n-o-s.eu
Photos of WINDCAT workboats are taken from www.windcatworkboats.com
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