"Oilcanning" filler material?

[Capttonyb]

Hi folks,

I am new to this forum and am in need of some help from the experts. . .

I am repairing a 20 foot sailboat whos hull was deformed through misplacement of stands during storage. The damage is "oilcanning". ie: the stands were placed on an unsupported section of the hull and the hull deformed inward. I have waited 2 seasons to see if the problem would correct itself. Unfortunately it hasn't. My question is; what type of filler should I use to fill the voids before re-glassing the hull. My initial thought is to use a foam in order to minimize weight. What type is available? What is best to use? Where can it be purchased? Is there another material that should be used as opposed to foam? All responses are welcome.

[gonzo]

It is possible to fix it with a hammer and dolly. The rest can be filled with an epoxy fairing compound.

[rxcomposite]

Fiberglass laminate has a memory. It tends to return to its original form after sometime. If it hasn't then you probably have structural damage and have to inspect the dry or innerside. Shallow dimple can be fixed by fairing compound and or "bondo" a micro balloon filled automotive putty. If thickness is over 1/4" thick, it will have atendency to crack or absorb water. you should add a layer (at least of glass over it and fair the edges.

Rxcomposite

[PAR]

Bondo type materials don't belong on a boat with any type of engine. Typically "oilcanning" is on metal hulls, between frames, not on 'glass hulls. If this is a problem on a 'glass hull, then you have bigger issues then some cosmetic repairs.

[Dutch Peter]

Originally Posted by gonzo

It is possible to fix it with a hammer and dolly. The rest can be filled with an epoxy fairing compound.

Gonzo,

Are you not mistaking a GRP for a steel boat? I never heard of this way of repairing indentations on GRP, but have not much experience with that.

[gonzo]

Oilcanning is referred to in metal hulls. I assumed he was filling in the hollows with some kind of fiberglass. Reading back, there is no mention of hull material.

[rxcomposite]

Capttonyb,

Without intention, your thread managed a lot of confusion including my reply which needed expounding.

The two gentlemen are right. Oil canning or "oil can effect" happens to the plating of steel ships when it encounters heavy seas or when submarines reaches critical depths.

I interpreted yours as "oil can damage" when a boat is propped up on the dry dock with oil can drums instead of adjustable chocks and stays.

Very rarely, in fiberglass boats, when the frames and stiffeners become pronounced due to shrinkage or warping of the skin, we have the "canvass top effect".

You mentioned "glassing the boat". I will assume you have a SINGLE SKIN fiberglass boat and the terminology of "oil canning" is loosely applied.

If it has structural damage, please consult MARINE COMPOSITES by Eric Green regarding composite repair. A more comprehensive and illustrated article appeared in PROFESSIONAL BOATBUILDER magazine some 5 years back. Perhaps Mr. Eric Sponberg would be able to help. The gentleman is a senior member of this forum and a regular contributor to PB magazine.

My suggestion was for cosmetic repair. It might be construed as repair on boat with structural damage.

Lastly, check if the boat is polyester resin based. If it is epoxy resin based, polyester will not bond well. Epoxy will bond to polyester but not vice versa.

Good luck.