Steel hull isolation: alternatives to foam?

Now, now, boys, don't be so hard on poor old polystyrene foam.
Yes, it burns furiously and with a toxic, black smoke. Yes, it deteriorates and makes a mess. Yes, it breaks off from whatever you glue it to. Yes, most glues, solvents and chemicals will eat it. No, it really does not belong on board a boat.

But.... it makes wonderful billets to hold up a floating dock

 

Not AP Teddy, AF is the stuff to prevent condense water, it is the "basic" metal hull insulation material.
NH is the better quality used as a fire retardant insulation. If its the only type of Armaflex available at your place, you can install it instead of AF but its a bit more costly.

Matt, please forgive, I´ve forgotten that purpose of styrofoam! It is perfect for a floating jetty (as long as you prevent it from UV rays).
I would like to go deeper into it, but have to deliver a yacht and so, I´m on a shake down and delivery run for some 14 days (if all goes right). My first 36 meter format, so the "Patron" is doing the job himself.

Regards
Richard

 

Thanks
Armacell link for AF properties seems to be broken.. And forgot to mention, I'm insulating wood/epoxy hull, so corrosion isn not an issue..

Styrofoam.. we made some styro-dummie-owls for crow hunting when we were kids.. a lot of fun

 

if weight is not a problem why not use wood, no seriously

 

Are you talking about hull insulation or decoy owls?

 

how many guesses you want

 

Here we are Teddy:

http://www.armacell.com/www/armacel...0441485EFA77484580256FDC00624346?OpenDocument

and, btw. as mentioned before, I produce in wood / Ep only and use Armaflex. Condensate and the resulting mold are the issue, not corrosion.

Regards
Richard

 

Two?

 

Insulation

I've tried most of them over the last 33 years of living aboard steel boats, mostly in BC waters. No matter how I tried to get a good vapour barrier , both styrofoam and fibreglas wool got soaking wet behind it and little bubbles started to appear in the paint. Fibreglas wool got sopping wet by the end of winter.
Friends tried sheet styrofoam and found it more expensive and far more labour intensive than if they had simply had the whole thing sprayfoamd, and it was nowhere near as good a result.
The use of the vaccum filled ceramic insulating beads added to paint, drasticaly reduces condensation, but doesn't eliminate it. Cork is organic and goes a beautiful moldy green by the end of winter, altho grinding it up and mixing it with paint may work to some extent. So far I have found no reasonable alternative to urethane sprayfoam, the best money one can spend on a steel boat. I have lived in a steel boat year round in mostly cold climes for 33 years and have no complaints about sprayfoam. My boat is warm and dusty dry in all conditions.
Electrical conduits should be installed before spray foaming . This will solve the running of electrical wires. For welding I scrape out the foam for three inches around the weld , then put wet rags over the entire area, weld, quench, epoxy, then spray the foam back in with spray cans. No problem.
Make sure you have several coats of epoxy tar on the steel, before sprayfoaming. Spray foam does little to protect the steel. Cheap latex paint over the foam drastically improves fire restance. You can get it free at recycling centres. Make sure you have at least a half inch of foam over every sq inch of steel, or it will drip condensation like a leaky faucet.
Brent

 

subertres

I just wondering does anybody used Subertres paint for metal boat?

 

Wood against steel is like putting wet blotting paper against it. I have done a lot of work this year repairing wood damage on steel boats , where it has resulted in steel under wood rusting right thru, where epoxied and spray foamed steel right next to it is in perfect condition, after decades.

 

A long time ago I picked up a 26' steel inboard that was pretty rusty inside. I cleaned it back to shiny steel (a LOT of work!) and used automotive undercoating over the entire inside of the hull. It cut the condensation drastically and reduced the noise level quite a bit. Unfortunately I sold the boat and moved away so I can't comment on the long-term durability.

I now have a 21' Sylvan that I am planning to re-do next winter and I see that it has 'spray foam' on the hull. I haven't decided whether to re-do the foam or what to use if I do but for a 1987 boat, the foam is still in good shape.

 

Drag your fingernails over the foam and listen for hollow spots. If you hear hollow spots, cut the foam out there, and check the condition of the steel under it, or whether it was epoxied..

 

I have recently purchased a CN 35, which is almost a carbon copy of an Alberg 37, but in corten steel. The hull has been insulated with Great Stuff Expanding Foam and painted over with fire retardant paint. I have read all posts here trying to figure out whether or not to rip it all out and put something else in...can't find Armaflex dealer in Canada...and it seems like there is a lot of difference in opinion about what to use. Anyone use a similar product for a length of time and have positive/negative experiences?? I am not too worried about fire, more worried about corroding my hull to bits.

 

Great stuff is far more water absorbent and more open cell than spray foam.It can soak up water like a sponge