Thornwick arrived in Bridlington harbour on Saturday, 26th June, 1948, having been launched the previous December. She was built at Scarrs Yard in Howdendyke for Col. A. Butler of Leeds. She replaced Royal Sovereign, sunk during the war, and Princess Marina, sold to Whitby, both boats being owned by Col. Butler.
The vessel weighed 126 tons, was over 30 metres long and her top speed was 11 knots. Her specification included five watertight bulkheads. Thornwick could carry over 300 passengers, and was provided with a main saloon, a tea saloon and ladies' cabin over two decks.
She carried a crew of seven with Mr G. H. Colbridge of Hull as captain, G. Johnson (Bridlington) as skipper, and F. Johnson (bowman of Bridlington lifeboat) acting as the mate. G. Johnson was skipper of Princess Marina during 1936, 1937, 1946 and 1947. In 1953 Mr Colbridge was still captain.
Mr Ken Lester was skipper for 12 years before leaving when Mr Gordon Fox took over the Thornwick. Mr Jack White and Mr Arnold Woodhouse were crew members when Mr Lester was skipper.
In 1968, Thornwick was sold and went to Poole in Dorset where she was renamed Swanage Queen. She had a refit in which one of her two funnels was removed and her bridge enclosed.
It is understood that later in her life she was on the Thames at Greenwich, her accommodation covered in and being used as a restaurant.
Thornwick is, according to the latest information in April 2016, being used as a houseboat on the Medway.
This information is taken from Any More For Sailing?, published by the writer in 1996, and there's more information about Thornwick in Bridlington Pleasure Boats, by Frank Bull, published in 2010.