I’ve added his Merchant Mariners service to his profile. Note that his name there is Joseph Shriff (not Sherrif) Newman.
"United Kingdom, Merchant Navy Seamen Records, 1835-1941," database, FamilySearch(https://familysearch.org/ark:/61903/1:1:KC7X-69M : 5 December 2014), Joseph Shriff Devlin, ; From "Merchant Navy Seamen1835-1941," database and images, findmypast (http://www.findmypast.com : n.d.); citing BT 112-116, 119-120, series BT349, The National Archives of the UK, Kew, Surrey.