Wished all sailboats were sold with good insulation >_<, like most narrowboats.

It is such a pain to think of having to do that after everything is built-up around the hull.

The best thing to do would be to use polyurethane spray foam directly on the hull. While insulating the boat, it also provides buoyancy (like Roger Taylor did with MingMing).

@rek haha oh wow that's wild. i guess the foam layer would also act as a potential bumper in case of *knocks on wood* sea-faring logs etc?

@rek My concern with that (from thinking and talking about green building for years, e.g., container houses) would be that the water vapour permeability of the foam (small but not zero) would eventually allow too much water vapour to get through and condense against the cold hull causing the foam to become water logged.

@rek I don't know of a tested solution but wonder if a thin layer of vapour-open material immediately against the hull could somehow be ventilated sufficiently to prevent water build up. I do know of a metal roof on a house near Cambridge, England, which uses something like that though I'm not completely sure of the details.

@edavies I was under the impression that if you didn't cut into it, or sanded it or wtr that it wouldn't be weak to water. But I've zero experience with the stuff, this is just from what I've read.
Tbh i haven't decided what we'll do. My first idea was to layer sheets of reflectix and polyethylene foam, with each layer glued down. I have rolls of the stuff with me rn

@rek All plausible insulation materials will let water vapour through eventually. How long it takes will depend on the material, of course, and the long-term history of the humidity of the air in the boat and the temperature of the hull so it's a matter of risk rather than being necessarily a problem.

The PNW in winter seems near a worst case, though. Maybe you'd be OK if you went somewhere with warm waters and dry air every so often to dry it out.

@edavies Winters here are fairly mild, but it might be because I am used to worse :).

@rek That's more of a problem than a Quebec winter because of the higher absolute humidity outside and therefore higher relative humidities in the cabin once the air's been heated a bit.

@rek is it maybe a cost/weight minimization thing? People preferring fast over comfortable?

I've never understood why homes don't have insulation. I get it from cost/complexity standpoint but it just helps so much to keep the dwelling comfortable with minimal cost relative to running HVAC.

@peregrine Adding something like spray foam isn't much added weight. I think it's just another way that builders cut corners, like how they'll bolt the deck to the hull instead of glassing the joint.

Also, most ppl don't live on their sailboats and don't suffer these issues.

Yea, dwellings ought to be insulated always. Even if it means more money, it's worth it and much harder to add afterwards :/

@rek thats a super bummer :( cutting corners seems to be the norm

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