We were liveaboards here in Seattle for many years and encountered the same issues you are having.  At some point you will need access to the inside of your bulwarks so filling them with foam is not a good idea.  I pushed batts of fiberglass insulation up into our bulwarks, the act of installing the batts was a bit ichy, but it solved the problem.  I have recently seen small batts of fiberglass insulation at HomeDepot that are covered with plastic like a grocery bag, they would surely be less ichy to install and easy to remove!

We also installed 1/4" closed cell foam under our cabintop overhead panels, under the trim panels below the decks and against the hull inside our lockers.  We ran 2 small ceramic heaters with fans to keep warm air moving around the boat.

I never came up with a good solution to the condensation that sometimes dripped from the ports on cold nights.  Dang, thinking about it make's me miss living aboard, have you  noticed how the water tank only seems to go empty on really miserable rainy, windy nights?

Kevin

I've been experimenting with insulation on Pygmalion W32 to solve the sweating inside the bullworks area and dripping into the cabinets and et al over time.

Ran across at Home Depot some "Duct insulation".  It has a 1/8" thick closed cell foam with a aluminum foil backing in 1'X15' rolles for ~19.00.  The adhesive on the foam is quite sticky and the foil backing is shiny and form fitting.

I've applied it to the cleaned surface of the bulworks about a month ago and yesterday was back at the boat to check on the results.

What I found is that the area w/o the foam was noticably wetter (I could see the water on my hand)  then where the duct insultion was installed (it felt damp and cold).  One piece had fallen down so I dried it out and reapplied on top of another piece to make the total thickness ~1/4" and I'll check in a month or so.

I think that the sweating seems to be worse on the sunny (south) side of the boat and above the water line. 

If the sweating continues to be more of an issue - I've though about mounting 4 small computer fans on the trim piece of wood that hides the opening in the center of the cabin.  The fans should blow air up into the center cabin bulworks and out the aft and forward space, hopefully drying out the area.  What slows me down is the wiring, power needs etc.  see image below of the area I'm trying to describe.  The white paint is a new from Petite anti mildew paint.

The 120V dehumidifier is another good idea.

Same area with insulation applied

I wish that I could use a 1/2" thick version of the same product.. I think that with a higher R rating this would work even better. 

I'll advise in as more data comes in.

Jay

PS I also though about the "pink" insulation for this area but had visions of glass particles dropping down and getting into everything - as well as absorbing moisture / water from leaks et al.

I've watched the "Holms on Homes" show and do envy the blue spray on foam they often use in garages voids -- but what a mess to apply post construction.