Dilemma

[Sixbrothers]

I’m installing a wind vane on the transom with four large bolts. The bolts go through the transom and large washers and nuts go on the inside. Because of the required position of the wind vane, two of the washers and nuts will be tightened on an uneven portion of the inside of the transom. It actually is about a 1/2inch step where the coring ends and all glass begins. The area is a very tight space to work. Any ideas?

[treilley]

Have some SS backing plates machined to match the angle.

[JimPendoley]

I've been planning this appraoch to making backing plates for all the stanchions on my old Pearson Vanguard. I have the same challenge: uneven undersides to tighten against.

I plan on temporarily putting a thin, filmy non-stick material like polyethelyne sheet against the underside of my deck where the bolts protrude. Then, I will create a strengthened with fibre epoxy slurry to the consistency of cold peanut butter, the underside of the backing plate will be coverd in plastic and coated with a 1/2 or so layer of epoxy slurry. This epoxy layered backing plate will then be attached loosely to the stanchion bolts and the epoxy will fill the low spots un the underside of the deck. I expect some oozing. Once cured, I'll remove the formed plate, trim to the outline of the backing plate and reinstall. The result should be a level and solid bolting platform against which I can tighten the nuts and washers. I can't think of any easier way to do it, but I'd love to hear of an easier approach if anyone else has a better way-I may wind up permanently epoxied to the underside of my deck.

[Sixbrothers]

The "step" in question is not at a right angle but rounded. I was thinking of some sort of epoxy that has the consistancy of silly putty before cured. With the nut and washer in the place and in a position that is disired, the putty could me molded into place. After it has hardened the nut and washer tightened.

[mitiempo]

Mixed epoxy with colloidal silica added until it is a peanut butter consistency works well. But the plastic is not necessary. Slather the backing plate with the thickened epoxy and loosely bolt in place until cured. The edges where the squeeze out is can be smoother with a gloved finger or plastic putty knife. When cured overnight remove the bolts and bed the fitting properly and you`re finished.

[Sixbrothers]

Thank you. I will collodial silica etc.

[JimPendoley]

It will make it a lot easier to remove the bolts if you coat them with something slippery, like paste wax. If not you may have a hard time getting them out again. Also, epoxy with silica does not add much strength; I should have said to add some kind of fabric like roving maybe. Just epoxy and colloidal will not have any strength to speak of.

[mitiempo]

Epoxy with colloidal silica added is quite strong. I have used this popular (for good reason) thickener in epoxy for over 20 years and had no reason to doubt its strength.

[Sixbrothers]

Thanks for the paste wax advice. I hadn't thought of that.

[hellosailor]

Epoxy and colloidal silia (or other thickener) is ideal, but unless you've got it on hand you'll get the same end result cheaper and faster using a tube of "plumber's epoxy putty" or similar from the hardware store. Some of that is rock hard in less than 15 minutes, so you may want to work with a helper, one to mix and apply inside the hull, the other to drop the bolts through so you can tighten it up right away. Bolts & backing plate, so the plate is snugged down in place, even if you don't erect the mast on that first shot.

Epoxy will go stale on the shelf, $5-10 of plumber's epoxy putty won't leave you with a hole in the wallet when that happens. (As opposed to buying cans of marine epoxy and thickener.)

Remember to wax the fender washers or backing plate too, in case you ever want to unembed it from the filler.