After many years of developing the Pre-Swirl Stator concept (PSS),Daewoo Shipbuilding & Engineering Co (DSME) of Korea has now completed the first sea trial with a ship equipped with a PSS.

The vessel was a 60m beam VLCC of the yard’s standard design built for the Greek owner Kristen. The sea trial took place in good weather (Bft 1-2) in early June and showed a reduction of 4.5% of the propulsion power compared to previous sea trial results for sister vessels without PSS. Being an oil tanker, the speed trial measurement could be carried out at the actual contract draught, equal to the design draught of 21m.

The application of PSS on this type of VLCC is contracted for a further two vessels for the above owner, and another nine vessels to be delivered to three other owners. Moreover, the yard has contracted the application of PSS to a series of ten large container vessels.

SSPA has been busy optimizing PSS for the above VLCC and other sorts of vessels since 2005. The work for the above VLCC was started in 2005 and was presented in Highlights no. 2006/2. At that time we expected an average gain of 4%, which has now been confirmed. It is also important to us that it supports the method for extrapolation of PSS model tests to full scale.