Just to state the obvious, but that skinny dipping experience probably had something to do with it. How long was it in the water and what kind of work was done to dry it out? You'd have to assume water got into all the engine internals as well as the gearbox and hydraulics. That should all have been drained, dried, flushed, etc.
Maybe you are lucky and it's just some external linkage that's frozen up.
