Fiberglass fire damage to a fiberglass boat

[Eagle Boats]

I am contemplating purchasing a boat that has been damaged by fire. The fiberglass appears to be mostly intact, but I was wondering if there may be problems that are not readily visible. Does anyone have any experience with such repairs, and if so, what I should be looking for.

Thanks

[marshmat]

If there's evidence of fire damage to the glass itself, it's probably a bad idea. Above 60, 80, 100 Celsius, depending on resin, the resins that hold fibreglass together begin to rapidly decompose, leaving weak spots and bubbles in the laminate. The result is hard and looks fine, but will fail catastrophically under a sudden load. I would strongly recommend retaining an accredited surveyor to do a thorough structural inspection. Without a good surveyor you have no way of knowing what is going on inside the possibly damaged laminates.

[Eagle Boats]

Thanks for the response. Its a lot easier to build new boats then to tackle a headache.

[SamSam]

Above 60, 80, 100 Celsius, depending on resin, the resins that hold fibreglass together begin to rapidly decompose, leaving weak spots and bubbles in the laminate. The result is hard and looks fine, but will fail catastrophically under a sudden load.
60 C= 140 F, 80 C= 176 F, 100 C = 212 F . It's not hard for a small fire in an enclosed space to build up these temperatures. It would seem that if that happens, not only would the skin of the hull itself be suspect but structural elements attached by fiberglass, such as bulkheads glassed to the hull, might be compromised first as they would be inside and surrounded on both sides by heat. At what temperatures do common boatbuilding resins of polyester, vinylester and epoxy sustain damage? What is the order of durability of the three? Sam

[marshmat]

Order of durability: In general, epoxy is best; vinyl- and poly- ester resins are 2nd and 3rd respectively. Ambient-cure resins are rarely good for service temperatures over 80 C (which, incidentally, is a standard post-cure temperature for most ambient cure systems). Heat WestSystem epoxy (one of the best), even with flame retardent hardener, to 100+ C and it is totally wrecked. But it won't really be obvious until substantially higher when you can see it turn brown. Bottom line, boat composites absolutely suck under fire/heat. As I said earlier, only a really thorough survey will tell you the condition of this boat's laminates; without an expert's eye and equipment you cannot tell what has happened inside this hull.

[jimslade]

Stay away, hidden problems.

[olearjo]

Order of durability: In general, epoxy is best; vinyl- and poly- ester resins are 2nd and 3rd respectively. Ambient-cure resins are rarely good for service temperatures over 80 C (which, incidentally, is a standard post-cure temperature for most ambient cure systems). Heat WestSystem epoxy (one of the best), even with flame retardent hardener, to 100+ C and it is totally wrecked. But it won't really be obvious until substantially higher when you can see it turn brown. Bottom line, boat composites absolutely suck under fire/heat. As I said earlier, only a really thorough survey will tell you the condition of this boat's laminates; without an expert's eye and equipment you cannot tell what has happened inside this hull.
Hello Matt,

I am an unfortunate owner of a boat that was in a large Marina fire. I am haggling with Insurance comapny on the way heat damage is being assessed. Do you know of written authoritative documentation the subject of heat damage to fiberglass boats? Are you an expert in thie field?

TIA Joe

[rasorinc]

You might check on David Pascoe's writings/books. He is an authority on
many marine issues. Stan

[olearjo]

Hello Stan,

I will do so and post any valuable findings to the thread.

Many thanks,

joe

[marshmat]

Dealing with insurers.... not fun.
I do not have sufficient expertise in this field to provide a legal opinion.
Informally speaking, though:
The fibreglass itself is not easily damaged. It will melt at a bit over 1700 C, far above what most boat fires would be.
The polymer resin in which the glass is set is the problem. Some of the common boat polyesters have a heat deformation temperature as low as 70 C. It is perfectly OK for a polymer to exceed its HDT when it is not under load, as most will regain their original strength when cooled. But if the HDT is exceeded while the component is stressed, it will flow and warp in an attempt to relieve the stress. When it cools, it holds the new shape and its strength is often less than before. So everything is now warped, squished and twisted, and has lost its ability to hold its original form. And just about everything in a boat hull is under some degree of stress when it's just sitting there at the dock.
You might check out John Murphy's Reinforced Plastics Handbook for a bit more detail; some of it is on Google Books- there's a section relating to your problem at
http://books.google.ca/books?id=jo7KwTldSNQC&pg=PA12&lpg=PA12&dq=heat+deformation+temperature+of+marine+polyester+resin&source=web&ots=o-9a2IV1Bq&sig=KH1aChaFQKs0VWRViWI8tT0OBPo&hl=en

[Ike]

olearjo

a couple of resources that might help

Amercian Composites Manufacturers Association http://www.acmanet.org/ they have a large archive of research on fiberglass composites.

If you need an expert on fiberglass try. Robert Schofield, Naval Architect. He ain't cheap but he's probably the number 1 composites guy in the US.

Mr. Robert A. Schofield
Robert A. Schofield, Naval Architect
4105 Lake Washington Road
Melbourne, FL 32934
Phone (321) 255-8331
Fax (321) 3554
rasna@attglobal.net

[olearjo]

Many thanks to everyone on the thread for all of your help and suggestions.

I am more confident that I can back up my requests that the hull be either classified in writing as unseaworthy (scrap) or seaworthy (with all factory warranties being intact).

Now for the battle...

[mrfixits]

Hi I hope I have posted this in the right area, but what I was wanting to know is ...I just picked up a 17ft fiberglass half cabin but was never told that the boat had been sitting in the bush and a small bushfire has gone though where the boat was sitting, the bushfire only seems to have started to melt the taillights on the trailer and the nav lights have a small amount of melting to the plastic , the stickers on the boat are all ok...I see one of the rego numbers has curled a little. So I was hoping that someone here might be able to tell me if this hull is safe to put out into the water again as the paint is not burned and still has a bit of a shine to it, any help would be great and if you need any more info please let me know.
Thanks for any help.

[PAR]

A lot depends on how quickly the brush fire moved through. If it was the fast moving type of fire associated with dry grass lands, then you're probably just fine, except for some cosmetic damage. If the fire moved slowly trough wetlands or dense ground cover, then the laminates may have been damaged.

Pictures might be helpful, but your description suggests it was a pretty quick moving fire and the heat limited in duration. You can wave a blow torch over the surface of a hull with no damage, but if you hold it in one spot for very long, then you'll have issues.

[mrfixits]

Sweet thanks I will post some photo's as soon as I work out how to...when you look at the boat you would never know that a fire had been near it but it has been sitting for about 5 years, so I guess all the rain would have washed it, and the guy told me he had just moved it to where it was when I seen it so he could sell it and the back of the boat was in long grass so I never seen that the lights were melted....the tyres on the trailer are still ok just the valve caps have melted a bit and the very bottom of the mud flaps, also do you want close up photos or just a full view photo.
Thanks again for your help.

[PAR]

Sounds like you're in luck, have fun and stay close to shore until you have some confindance.