SS Cushag was sold once more, this time to a London broker, from whom she was purchased by the Isle of Man Steam Packet Company in May 1920, at a cost of £22,000 (equivalent to £). Small and drawing so little water, she was mostly used for cargo trade in the Island's smaller ports - Port St Mary, Peel, Laxey and Castletown. After over 20 years service with the Company, she was sold to London agents in January 1943, and then went on to Stornoway on the Isle of Lewis for four years. She transferred to Kirkwall in Orkney in 1947. "Cushag"
Castletown, Dorset is found in the village, close to the entrance of Portland Port. The area still features several hotels and pubs, largely established for the navy personnel that once came from the port. The Osprey Leisure Centre is located in Castletown, which was formerly known as the Boscawen Centre, and was opened to the public in May 2007. Originally it was a private Royal Navy facility during the 1980s. Castletown also holds the Portland Community Hospital. This was originally a Royal Naval Hospital which served Portland's naval base from the late 19th century until 1957, when the hospital was handed over