Condensation

[KenMcCulloch]

I was visiting Border Maid today to do a bit of tinkering and was surprised to find condensation all over the deckhead. Not the coachroof but the underside of the main deck. I was a bit surprised at that, I've seen it in steel and plastic boats before but not been aware of it in a wooden boat. The deck is t&g boards (some sort of pine I think) which has been covered with glass cloth & resin on the outside. There are several ventilatrors open but the humnidity has been high and it's been pretty cold at nights recently.

Is this unusual, should I be worried?

 

[oldharry]

Absolutely normal as it gets colder IME. Wooden boats can 'sweat almost as much as plastic if the interior has warmed up during the day with a bit of sun, followed by a cold night which cools the timber down quicker than the internal air mass. Worse still if theres a heavy dew as evaporation cools the wood even faster.

 

[chrishelen]

I had a look over a bristol channel pilot cutter last xmas, the whole inside deck head was dripping,i was told its was ok,it was closed up tight as a drum,i didnt like it and thought some through ventilation must help.

 

[KenMcCulloch]

Thanks for those, I do try to keep her well ventilated. The surprising thing was that the underside of the coachroof was quite dry. It may be that the paler colour of the deck makes that slower to take up any radiant heat from the sun during the day. Maybe black decks are the answer.

 

[Poignard]

I notice that on my boat. If turn in without leaving a hatch open, the underside of the deck [grp] gets condensation on it but the coachroof [1/2" plywood] doesn't. Both deck and coachroof are painted the same colour [blue grey].

 

[KenMcCulloch]

[ QUOTE ]
I notice that on my boat. If turn in without leaving a hatch open, the underside of the deck [grp] gets condensation on it but the coachroof [1/2" plywood] doesn't. Both deck and coachroof are painted the same colour [blue grey].

[/ QUOTE ]
My coachroof is also 1/2" ply, maybe it simply is a better insulator than the solid deck and so doesn't attract condensation

 

[oldharry]

It also depends how moist the air is inside. My old Eventide would sweat much more if there was a couple of inches of bilge, than if I pumped her dry.

Having a good through draft seems to make a big difference too.

 

[dur]

I was on Wind Song last weekend and noticed water on the floor and table. Then I looked up and noticed that the deckhead (ply) was dripping. I suppose it was the warm still days and cool nights. Bit worrying though. I guess more ventilation is required somehow.

 

[burgundyben]

I suffer the same.

I have a cover over the cockpit and leave the cabin door open, that way as the cover billows the air gets moved around a bit.

An aquaintence tells me keeping a cactus growing the cabin works....I've never tried.

The only year I had a dry cabin was when I had the dehum running.

HTH