Sea Sick by Iain Rob Wright

After a violent and traumatic incident, Police Officer Jack Wardsley’s superiors have placed him on forced leave. He boards The Spirit of Kirkpatrick, a cruise liner built for relaxation and fun. Pretty soon, however, Jack realizes that fun in the sun is the last thing he’s going to get.

There’s a virus onboard and it’s turning people insane – and there’s nowhere to escape in the middle of the sea. Jack needs to put his anger to good use and find out who’s responsible before it’s too late. So much for his vacation… (More info)