Condensation in the V-berth is always an issue our marina neighbors complain about.
We too would sometimes wake up in the morning, just to find out that we're laying on foam, that's damp or sometimes plain wet. Instead of investing in nice memory foam (think $$), we would buy cheap camping foam, that we threw away every three or so months, because it simply wouldn't hold it's shape and we walked around with backpain and never got a good nights sleep.
So, while it might be Mission Impossible to get rid of condensation, we found a way to at least keep condensation away from our bed and bodies.
Anyway... here's what we did:
in the fall of 2008, we invested in two real spring mattresses from a local shop, that otherwise would supply RVers. We figured, we needed to buy two halves to be able to simply fit the thing down the hatch and to have more flexibility when needing acces to the storage spaces underneath. For a fee, they cut it to the shape we requested (we did all the measuring). Both the mattresses and the cutting fee cost us about $850. We did pick up the mattresses ourselves. From the order to the pick-up just 7 days have past.
If this would be our weekend boat, we would probably never invest $850 into a mattress, but this is our liveaboard boat and it makes life a lot easier, if you don't walk around like a zombie with backpain. It was one of the best money in regards to the boat spent so far!
So, the mattress was awaited by a home-built wooden platform. It is about 1,5 inch off the fiberglass. This enables air to circulate without actually touching the mattress.
