Condensation in the forepeak

[mm5aho]

I've noticed when I sleep in the forward bunks that the lack of lining in there means (at least in Scottish waters) that breath condenses on the inside of the fibreglass decking which forms the ceiling in that cabin.
This condensation is a pest. It makes things wetter than they need to be.

To solve the problem I see two directions of solution:

1. Ventilate:
There is no direct ventilation there. We have a special piece of teak. It is rectangular, so it has three dimensions. When put in the hatch, it can give three levels of opening. 25mm, 50mm or 150mm. A variable ventilator. But underway, this isn't practical, so no ventilation then.

2. Insulate:
I had thought to line the area with foam backed vinyl or similar, but can foresee issues like mould, moisture in the foam, tears in the fabric? etc. Apparently a smelly job glueing such stuff, but there are ways?

So what opinion on these two potential solutions? Or are there more ways to fix it?

If ventilator, what type to minimise water ingression? If, in rougher weather we ships some green over the bow (not unheard of), then we don't want a wet berth - that just makes it worse to have salty wet sleeping bag than plain wet!

[DaveS]

I've noticed when I sleep in the forward bunks that the lack of lining in there means (at least in Scottish waters) that breath condenses on the inside of the fibreglass decking which forms the ceiling in that cabin.
This condensation is a pest. It makes things wetter than they need to be.

To solve the problem I see two directions of solution:

1. Ventilate:
There is no direct ventilation there. We have a special piece of teak. It is rectangular, so it has three dimensions. When put in the hatch, it can give three levels of opening. 25mm, 50mm or 150mm. A variable ventilator. But underway, this isn't practical, so no ventilation then.

2. Insulate:
I had thought to line the area with foam backed vinyl or similar, but can foresee issues like mould, moisture in the foam, tears in the fabric? etc. Apparently a smelly job glueing such stuff, but there are ways?

So what opinion on these two potential solutions? Or are there more ways to fix it?

If ventilator, what type to minimise water ingression? If, in rougher weather we ships some green over the bow (not unheard of), then we don't want a wet berth - that just makes it worse to have salty wet sleeping bag than plain wet!

I fixed foam backed lining into the forepeak of my first boat. I used Evostik which worked well, but the fumes damn near killed me. I managed to get the hatch open when I felt myself feeling woozy then fell back. Fortunately before passing out I remembered that the fumes are heavier than air and had the strength to get up again and stick my head out of the hatch.

[wully]

In mah wee boatie I took all the side and head lining panels off, cleaned the bare GRP the hot glue gunned on cheap camping carry mat.
Once the panels were back up the cabin is now much cosier- and virtually condensation free.

( Decathlon in Glasgow is a good source of cheap carry mat. As well as cheap but good thermals, waterproofs and most importantly, Ovomaltine biscuits.)

[mm5aho]

Camping mat sounds OK. It'd be that thick stuff perhaps 15-20mm thick??

I was wondering about condensation behind any lining though?

I notice that the thin ply sheets in the main saloon, which are vinyl covered, do get condensation behind them, and some mould (or other green gunk). Taking the panels off and cleaning up behind is OK, and do that every few years, but if the vinyl were glued on permanently, that's not possible. But maybe it doesn't happen?

[DaveS]

Camping mat sounds OK. It'd be that thick stuff perhaps 15-20mm thick??

I was wondering about condensation behind any lining though?

I notice that the thin ply sheets in the main saloon, which are vinyl covered, do get condensation behind them, and some mould (or other green gunk). Taking the panels off and cleaning up behind is OK, and do that every few years, but if the vinyl were glued on permanently, that's not possible. But maybe it doesn't happen?

If you use closed cell foam mat it should be impermeable to vapour, so no condensation, providing it's well stuck down and any gaps are filled.

[wully]

Camping mat sounds OK. It'd be that thick stuff perhaps 15-20mm thick??

If 15-20 mm is the same as about 3/4" then yes