Captains outrageous - Joe R. Lansdale

Hapless chicken-plant guard Hap Collins gets into trouble when he takes his best friend Leonard on a Caribbean cruise. The two find themselves abandoned in Mexico, saved from armed attackers by a geriatric fisherman and his lovely daughter, who's currently having to fend off a Mexican mobster who is also a practising nudist... Trying for once to stay out of other people's business, Hap returns to East Texas but is overwhelmed when he learns of the senorita's murder. He then persuades Leonard to return with him to Mexico to even the score.