sentence: inscription reads : to the glory of god and in memory of these three officers and one mechanic of the royal navy who fell on the mole at zeebrugge on st george 's day 1918 and have no known grave wing commander brock f. a. o.b.e. lieutenant commander harrison a. l . v.c. lieutenant hawkins c.e.v. mechanic second class f/50269 rouse j. wing commander frank arthur brock ( 29 june 1888 -- 23 april 1918 ) was a british officer of the royal air force who devised and executed the smoke screen used during the zeebrugge raid on 23 april 1918 , in the british royal navy 's attempt to neutralize the key belgian port of bruges-zeebrugge during the first world war .