Hi Andy,
The best idea might be to contact the yacht clubs* in the area that you visit. Not
commercial marinas.
Usually this time of year there are a lot of races and cruisers going out for the day. Someone may need crew.
There are yacht clubs all over your proposed area, as I remember.
Good luck!
(and I hope you're not reduced to drinking your own urine...lol!)
*Or "sailing clubs".