From The Arthur Conan Doyle Encyclopedia
William Addy, R.N.R., 111 W.S.E., D.S.C., was a trawler skipper from Hull, UK.
Addy was know for two notable naval achievements with the Conan Doyle H240 : he had the world's record for trawler catch, namely £10,790  made in 16 days' fishing, but most importantly he fought a German submarine with success on 20 june 1918 (see detailed report of the battle here). For this exploit, he was awarded the military decoration : D. S. C. (Distinguished Service Cross) on october 1918. 
When Arthur Conan Doyle learned about this splendid battle on his namesake, he wrote to William Addy and sent him a silver cigarette case with a congratulation carved on it : "To Skipper William Addy, D. S. C., from Arthur Conan Doyle. In memory of June 20th, 1918." In return, William Addy sent him the trawler's bell which bore the name of the boat "Conan Doyle". The bell was proudly exhibited in Conan Doyle's living room.
- Sir Conan Doyle's Gift (The Daily Mail (Hull), 9 february 1920)
- Author Honors Skipper of Ship Named Conan Doyle (The Boston Post, 14 april 1920)
- His Trawler Namesake (Sunderland Daily Echo And Shipping Gazette, 10 february 1920)
- In some articles £10,790 is replaced with 10,790 lbs.
- source : naval-history.net