Insulating the boat

[mrangry]

I am currently internally refitting a Moody 33 and looking at insulating against condensation whilst it is in a stripped out state. I realise that ventilation is key but I am interested in hearing the views and experiences of anyone who has knowledge of this and the best way to tackle it and with what products.

I have been looking at closed cell foam on eBay (which is very pricey) but have also read online of people using foil backed products and to be honest the list seems endless.

 

[salar]

I have used closed cell foam for Hawke House on my hull, covered with van carpet. Coachroof sides foam backed vinyl stuck on, roof is ply faced with foam backed vinyl. All very cosy now!

 

[pmagowan]

I have explored this quite a lot and it is tricky. Closed cell foam seems a reasonable solution. You have a number of options:

Spray foam: good r value, conforms to shape, ease of application. However it can be messy and impossible to remove.

Solid Foam sheets. PU or EPS. They don't fit as neatly but are cheap and can be removed more easily.

Flexible foam. More expensive but better fit.

Aerogel: very good r value. Very expensive. Easy to fit

Then you have the moisture problem. If you insulate you need to control vapour otherwise it passes through the warm insulation and condenses behind it on the cold hull. This can cause rot and smells. Well sealed closed cell foam would work or a vapour barrier can be applied. Spray foam doesn't have this issue.

Then there is the waterline issue. What to do in the bilges? Some people leave it uninsulated to prevent bilge water contamination of the insulation.

Whatever you choose, if you do it right it will make a big difference.

 

[Seajet]

When I and 2 chums lived on my boat I fitted polystyrene tiles between the ply headlining and the deckhead.

Make sure the polystyrene is flame retardant, but I think that's standard now.

I also fitted silver foil as insulation; partly as a radar signature enhancer, pretty vague but seems worth a try along with the insulation properties - I once asked a passing ship how we looked on radar, the answer was ' fine ' but that's not much analytical use...

 

[Caer Urfa]

I sleep aboard every month for 10 days at time all year round due to the distance and travel costs from my home to the boat, last year I was getting condensation where the cushions
are against the hull even though the hull has foam back vinyl lining.

I simply insulated the area and below all the cushions with Thermal insulation foil which you simply cut to shape with sissors :-
http://www.wickes.co.uk/Wickes-Ther...match||plid|&gclid=CM_C5OuAhskCFcZuGwodM1AE6g

Oh what a difference it has made and no condensation, but the biggest difference I found even at zero outside temperatures was to leave the saloon side window open just about the thickness of your index finger during the night, sounds mad but it works .

Mike

 

[pmagowan]

The ventilation problem on a boat is a difficult one and I have been trying to come up with a reasonable solution, finding myself on a damp boat. It is easy to just leave hatches and vents open but then how do you retain any heat? You can get mechanical ventilation with heat recovery for houses and even for small rooms like a bathroom. This uses a small fan to circulate the air but instead of just passing it straight outside it allows the exhaust air to preheat the incoming fresh air. this has a number of benefits:

1)You don't simply lose heat to outside
2)You get good ventilation throughout, even if it is not a windy day
3)It acts like a dehumidifier as the fresh air is dry and the relative humidity drops even further when it is heated up

The one difficulty is that you need to have a fairly airtight house for this to work on otherwise the ventilation due to leaks is going to outweight the MVHR. Of course, on a boat this is not a big problem because they are designed to be well sealed. I am planing to see if it is possible to integrate this with an eberspacher airtronic so that you can use the same ducting for ventilation and heating. More ducting is needed for exhaust, to extract the stale moist air from the heads, cabins and wet locker.

It should reduce the fuel requirements for the ebby and make the entire space inside dry.

 

[Carmel2]

I sleep aboard every month for 10 days at time all year round due to the distance and travel costs from my home to the boat, last year I was getting condensation where the cushions
are against the hull even though the hull has foam back vinyl lining.

I simply insulated the area and below all the cushions with Thermal insulation foil which you simply cut to shape with sissors :-
http://www.wickes.co.uk/Wickes-Ther...match||plid|&gclid=CM_C5OuAhskCFcZuGwodM1AE6g

Oh what a difference it has made and no condensation, but the biggest difference I found even at zero outside temperatures was to leave the saloon side window open just about the thickness of your index finger during the night, sounds mad but it works .

Mike

+1 Also in the summer it kept the boat a lot cooler, not much of a problem if you are in the UK, but Greece and Turkey it was a big help.

 

[Trundlebug]

I've recently tried using some expanded PE (polythene / polyethylene) and it's excellent.
Closed cell
Flexible
Good insulator
Available in a number of different thicknesses
Inert
Light weight
Maybe not so good in a fire though
Available in black or white
* Edit: Forgot to add, it's great to cut and work with. No mess, unlike Kingspan!

But to buy is a bit pricey I thought.

However it is widely used as packaging material - the stuff I used was about 10mm thick and a sheet was packed both sides of my solar panel. I recently cut out 2 pieces and have inserted them in the saloon windows, they really keep the cold out, and can be quickly inserted and taken out as and when required.

I also cut out some square pieces 500x500 and placed them under the Bomar hatches in the roof.
What a difference! It's really effective.

Worth considering

 

[Kelpie]

Just picking up on the window idea- I use pieces cut from a cheap foam camping mat instead of curtains. A push-fit into the window gives total blackout and eliminates condensation. I may have stolen the idea from Dylan, IIRC.

 

[pagoda]

I have used closed cell foam for Hawke House on my hull, covered with van carpet. Coachroof sides foam backed vinyl stuck on, roof is ply faced with foam backed vinyl. All very cosy now!

I did the same. Old foam backed stuff was crumbling away. Removed. Abraded the surface and glued Hawke House closed cell foam and "van lining" on top. I now have almost 15mm of insulation and a pleasant surface to touch. Well worth the effort!