Service operation vessels (SOVs) provide an offshore O&M base, with staff working from the vessel for periods of two to four weeks at sea. SOVs are the preferred way to maintain wind farms located far from shore.
What it costs
The charter day rate for an SOV is about £30,000 per day depending on size and fit out (excluding fuel).
Who supplies them
Manufacturers: Astilleros Gondanm Cemre, Damen, Royal IHC and Ulstein.
Vessel operators: Acta Marine, Bernard Schulte, Bibby Marine, Esvagt, Louis Dreyfus Travocean, Østensjø Rederi and Vroon.
Fleet of SOVs servicing fixed wind farms. Image courtesy of North Star Renewables. All rights reserved.
SOVs offer accommodation, mess, and welfare facilities for wind farm technician staff, as well as workshop and spares storage. SOVs stay at the wind farm for up to four weeks at a time, at which point they return to home port to restock and change crews.
Access to the wind turbines is achieved either by smaller CTV, daughter craft, by helicopter, or directly from the SOV using a turbine access system.
SOVs have operational speeds of up to 15 kn. They are equipped with dynamic positions systems. Vessel manoeuvrability is a key requirement to reduce positioning time and therefore costs. For this reason, there is little use of surplus platform support vessels (PSVs) from the oil and gas industry. PSVs have a more important role in supporting installation and commissioning.
SOVs can typically accommodate a crew between 50 and 100, of which up to 50 may be wind farm workers.