The London Mariner with a gross tonnage of 5650 was built at Haverton Hill shipyard it was owned by Furness Withy & Co.Ltd. The keel was laid on the 31st May 1920 and the ship was launched on 21st June 1921. 
Picture Stockton Archive
A Pictorial History of Stockton-on-Tees
Would one of the many knowledgeable visitors to PictureStockton be able to help me with my quest? How can I find out details of the type of vessel that one of my ancestors (who was a Master Mariner) sailed on in the early 1800″s