Royal Navy: HMS Mersey fitted with "underwater spoiler" to increase speed alongside suite of improvements

A Transom Flap has been installed on the Portsmouth-based vessel HMS Mersey. The ship’s social media team described it as an “underwater spoiler”. The transom on a vessel is the aft transverse surface of the hull that forms the stern.

The flap increases speed and decreases drag as the ship sails through the water. With the upgrade installed, the River-class offshore patrol vessel is now faster than some of her counterparts including HMS Severn and HMS Tyne, the HMS Mersey team said.

Pictures showed what the upgrade looked like while the ship was in the dry dock. Several other upgrades have been installed during her life-extension programme. A Ministry of Defence spokesperson previously said HMS Mersey’s engines have been overhauled and her propellers, shaft line and rudders being removed and reinstated.

Her communications systems have also been updated and modernised, alongside her accommodation and living quarters. HMS Mersey has also been emblazoned with a fresh coat of paint. Her upgrades were made across a nine month stay in Falmouth dockyard in Cornwall, with plans already in place for her to sail on frontline deployment.