No fear, I've had enough of floating in the sea. We were actually sleeping after a lunchtine BBQ on the beach with a few glasses of chilled wine when we were woken by a surfer tapping on the window to say we were floating off. Even in that short space of time I was seasick so I do'nt think the sea's for me. Do they do amphibious caravans nowadays like Queen Victoria used to have when she went skinny dipping with John Brown, something like that might be nice?
Jimmie, to go back to this foul smell in your caravan, had you intended to go fishing by any chance? If so, you must be very careful with rods, lines and bait. You must never let bait come into contact with interior fabrics. If that is the problem, you may have to purchase a specialist odour removal spray that you work into the fabric (or indeed carpets or headliner), and then thoroughly wash out with warm water after at least 40 minutes.
The important thing is then to let it dry properly, 24 to 48 hours, dependent upon ventilation, temperature, and, of course, humidity levels. If there is still a malodourous element, then repeat the process until eliminated.
There could be other obvious things such as misplaced items of food, or, I am afraid to say, personal hygene. I do hope that this helps.