Ride with great care
I have two Dahon Mariners on board - I found the lowest online price a few years ago was Boater's World. Dahon sort of dominates the market for low end folding bikes (and for casual use low end is fine) and the Mariner is one with some of the components (particularly the rear cluster and chain) in a corrosion resistant metal.
Very Important Note - the Dahon owners manual points out that folding bikes do not ride like normal bikes, a fact I ignored because I'm a pretty experienced rider. I know to hit the rear brake before the front and put my weight on the pedals and push back off the bars a bit when breaking on a steep hill (like a hill you might find near a marina) My 14 year old didn't know about that technique, and I forgot to tell him.
Bottom line, these bikes flip over their front wheel much more easily that you might imagine. He was wearing a helmet, thank god, otherwise it would have been a life changing accident rather than just ending the trip. He was knocked out, ended up concussed, plus he broke *and* dislocated his elbow.
Ride with great care.
Edit - storage is also an issue - in the end, all things considered, I really wish I had not bought them.