U is for Unsafe Acts by Bill Kirton
Blurb (from Goodreads): An offshore platform in the turbulent North Sea is a dangerous place…
…there’s the isolation, the machinery and the constant battle with the whims of nature. For Ally Baxter, a safety officer on Falcon Alpha, those whims take a deadly turn. When his workmates decide he’s gay, an evening ashore turns ugly as they indulge in some drunken queer-bashing. Later his body is found along the route the group followed.
For DCI Jack Carston, the case seems simple enough until a second murder is discovered. This time it’s the prostitute Ally always visited—a young mother with a baby son. Complications mount as Carston, in addition to his investigations, has to deal with an inexperienced officer under his command and a disciplinary charge brought against Carston himself by a vindictive superior officer.
The obstacles keep piling up, but more is to come when he finds evidence of a plot to wreck the platform itself.