Your thoughts on sprayed foam insulation for aluminium yacht hull

I much prefer a fitout that can be removed easily in sections to inspect and check the hull interior every 10 years. Then your steel boat will last indefinitely.

But in a fully seamless fitout ( should never do that on a steel boat IMO) well applied foam does fully stop condensation but all the metal should be buried, there are a lot of poor foam jobs too.

On alloy builds not painting the inside means you can afford a better type of insulation.

On one build the client used closed cell fire retardant mats made for the house moving industry, about 17 mm thick similar to the outdoor sleeping mats. I think they line the trucks with them.

 

We used to deal with a yard in the US who were building our designs (at my previous company) under licence. The yard always wanted to spray foam the hulls. As you say Eric, this is common in the US. But it is not common in the EU, in fact you wont find many advocates at all. Especially Class/Flag. If i recall I think one company got rather annoyed at us not agreeing to spray foam (citing Class as an example) and spent some time/money getting it through for Class approvals. Can't recall if they succeeded. We still don't recommend this method, despite what may be common elsewhere.

I also vaguely recall as you point out Mike:

This was another reason why, apart from those already mentioned, why we do not recommend spray foam.

 

I've decided on the same approach. While I have seen for myself the benefits of a thick coat of foam, via an aluminium 42ft sloop that spent a night layed hard over resting on a reef.
The foam prevented mayor ruptures from slamming by wave action, instead was reduced to buckled plates with only one minor tear.

But getting the foam out and off the frames etc was an epic task, took 4 guys a week of stripping before the boat was ready and safe to replate. We did note the hull althought oxidated had sweated under the foam.

Another project in 2006, remove aluminium hull plates on 29m sloop to rebuild 4 seperate intergral bilge fresh water tanks that had corroded thru. Same problem removing the insulation foam from around the tanks so we could safely weld and not have a 29m melt down.

Thanks to all for your interesting experiences and ideas

 

I had a call on this today. Usual problems to find insulation on hand anywhere.

There are fire retardant self extinguishing Expanded polystyrene sheets available that are manufactured for housing underfloor insulation.
Looks like would conform to all the standards. Here's one website :

http://www.homeefficiencygroup.com....dPolystyreneInsulation/tabid/305/Default.aspx

Another is called foilboard in Australia available in a range of thicknesses.
http://control.visionscape.com.au/S...ies2010comau/Foilboard_Technical_Brochure.pdf

Available cheap, very light. But we would never touch it because of the fire risk before.


Although I haven't properly looked into it it looks like it would do admirably now its self extinguishing common and cheap.

 

Daiquiri: Do you have names for other brands besides Armaflex here in Europe?
Much obliged!
Walter

 

The first one that comes to my mind is K-Flex: http://www.kflex.com/default.asp?l=en
Italian brand, very good quality closed-cell foam in sheets and tubes, very similar to Armaflex. The prices can be seen in the attached pdf file (in Italian, sorry).
You can usually get around 30-35% discount on these prices. That's a curious way of doing business here in Italy - they give you a price list and then tell you that, being a builder, plumber or whatever, you are entitled to have 30-40% discount...

Then there is also Navycell, produced by Trocellen: http://www.trocellen.com/images/trocellen/insulation/downloads/eng_troc-navycell.pdf - similar in composition to Armaflex.

Cheers!

 

Mike, foilboard is sort of what I had in mind. As you may recall my house is insulated with layers of this stuff under the cathedral ceiling. I've been quite happy with it.

The only real caveat about the stuff is its potential to generate huge clouds of toxic fumes in a fire. OK, it might not burn in itself but a hot enough heat source will I think cause it to outgas quite badly.

As I need to add a bit more insulation to the workshop I might buy another sheet or 2 of the latest stuff and heat some offcuts up, see what happens.

The other caveat I've had is the exposed edges soaking up water but it might not be an issue, or easy enough to seal them after cutting to size.

PDW

 

If you are worried about the possibility of fire in your workshop, then you should avoid polystyrene and polyurethane sheets; the former because easily flammable and the latter because it produces some very toxic fumes during combustion (Hydrogen cyanide and acrolein, for example).
You should use sheets made of polyethylene or polypropylene foam instead.
Cheers

 

Slavi
Not any more, the Expanded polystyrene product we are talking about has a fire retardant and is self extinguishing. It's produced here en masse for the housing industry. You can read the flammability idex in the pdf I posted before.

Peter
All the foams gas off when the fire gets intense.

 

I've started research for supply of expanded polystyrene here in China, so far nada plus I need to test samples myself any I do find..suppliers here often make claim to non existing properties.

 

Daiquiri,
apologies for responding so late, I was away. Thanks a lot for the links! It appears they don't have dealers in Scandinavia, but I will contact them to make sure.
Cheers
Walter

 

Think positive - it might be a good business opportunity for you.

 

I had a look at the Italian Trocellen material, its very simular in composition and assembly to several Pyrotec products we use on our 12m to 20m HS RHIB in combination with accoustic barriers.

I intend using Pyrotec or Halyard composite thermal/accoustic in the engine space and 60m closed cell PU foam slabs glued against the skin for the accommodations length of the hull - bilge WL to sheer & deck heads.

The yacht owner, a very experienced yachtie intends sailing Antarctic and Southern Oceans.