Falmouth is a town, civil parish and port on the River Fal on the south coast of Cornwall, England. Falmouth is famous for its harbour. Together with Carrick Roads, it forms the third deepest natural harbour in the world, and the deepest in Western Europe. Read more on Wikpedia
There is no documentary evidence that Lowry ever visited Falmouth though he may have visited the port on a family holiday to Looe, Cornwall in the early 1920's. Lowry refers to the port in his first novel Ultramarine when Nikolai, one of the crew of Oedipus Tyrannus, relates that he caught venereal disease in the port; “In Falmouth I make a fire to my my pipe, knaw, and I stood listening to the children playing - laughing same troubles as Norwegian children. But Falmouth left me a souvenir of my wisit (sic) , he added laughingly, 'the third time I have had a souvenir in England”. (Pgs. 19-20). Lowry is probably referring to the fact that Pyrrhus - the ship he sailed on to the Far East in 1927 - arrived in Falmouth on 24th April 1927 and went into dry dock in Falmouth the next day until May 1st 1927 when she sailed to Swansea.