Another approach, provided that you're mostly dockside, is to fit out your Gulfstar 41 with A/C and heat. If you're a liveaboard in CT, you'll probably want to do that, anyway.
The A/C will remove the excess humidity, and the heat will help you and your guitar's glue to survive the freezing temps up there.
I've had a wonderful old guitar aboard for some 22 years on my 42' sailboat, and an additional 15 years on a previous boat. It's a Japanese knockoff of a Martin D-28 which I bought in Hong Kong many years ago ($35 with a hard case!!!), and it's survived very well over the years.
NB: I don't keep my real D-28 aboard, though :-)