Hull damage from Vynabond
Yes. And it did not involve huge amounts.
So its not unheard of.
They changed the Vynabond formula a couple of years ago with no notice. Now you need to dry each surface for an hour before pressing together rather than 20 minutes.
Lots of “Theoretical” Problems Noted
– Last Updated: Dec-29-09 10:54 AM EST –
As for experience rather than theory, I've installed foot rests on three royalex boats. One with screws, 2 with rivets, all near water lines. Two of them sealed with plain old bathroom caulk, one (gasp) unsealed that has yet to leak in 4 years. I like rivets better as they are smaller and less prone to catching on anything. No problems with leakage, no tearing the hole larger (and I can put a lot of stress on it with my legs). They may make the canoe LOOK less "Pretty," but who cares. They help you paddle and with a damaged right leg, it's one of those things I do to keep it from going numb as easily. WW
How do they seal better in this case?
– Last Updated: Dec-29-09 1:57 PM EST –
A pop rivet only squeezes the washer (on the outside of the hull) against the metal frame of the footbrace (on the inside of the hull), squeezing the hull between them. Bolts (NOT "screws") do exactly the same thing, but they do it much better, so that they can even squeeze much larger-diameter washers against the hull with the same or greater resulting PSI than a pop rivet can do, even though pop-rivet washers are very small. Sorry, but I don't buy it.
I can imagine that a pop rivet might seal better on the "back side" if NOTHING is being fastened there (that is, if the object being fastened is being held to the "front surface" rather than the back), because in that case, the expanding plug on the back of the rivet would squish against the sides of the hole in the hull, but that's not the case when installing a footbrace.
I think you could get a bolt to seal
… every bit as well as a pop rivet. But, I don’t think you could do it with the same thinness on the outside of the hull.
As someone else said, there are lots of theoretical issues with riveting in footbraces. But so far, no real-world problems with it.
Yup, just like the theoretical issue…
… with using bolts instead of rivets (rock impact causing the hull to be torn by a bolt instead of shearing the top off the rivet).
I used to have a Royalex boat on which I’d installed a footbrace using bolts. Steel is so much stronger than aluminum that it would have been a simple matter to grind the head of the bolt to the same thickness as a pop-rivet head and still have much more strength than would ever be needed, but since the bolt heads only protruded 3/16ths of an inch, I didn’t worry about it. I also could have gone to the hardware store to buy bolts more suitable in size, and in that case the heads would have protruded less than half that amount (still, the ones I used never caught or snagged on anything during the three years I paddled that boat, and I mostly paddled it in log-strewn creeks).
Either method is fine, because this sure ain’t rocket science. I only posed my question since it seems a lot of people take it as a “given” that one always uses rivets in this case.
rivits vs. bolts
Biggest problem with bolts is two fold, one you have to have something to hold onto the secure the bolt, so it’s not smooth and two it’s difficult unless you buy in quantity to get truss head bolts the only type that’s nearly as flush as a conventional big head rivit.
Bill H.
sealing hole
Done correctly the hole in the Royalite should be drilled oversized, filled with epoxy and once set redrilled to accept the bolt/rivit. The epoxy will permanantly seal the Royalite, something that no caulk can ever do.
Bill H.
Not to beat a dead horse, …
– Last Updated: Dec-30-09 12:16 PM EST –
... but I did already address this in my reply to Clarion. My bolt heads never caught on anything in three years of paddling among fallen logs (the side of a canoe is not too prone to hard scraping), but grinding the bolt head down to avoid that possibility is simple. The torque you apply is so tiny before the hull begins to crush (try it, you will be amazed) that even the slightest trace of an "edge" for a wrench to grab is all you will need (actually, now that I think about it, when I installed my footbrace, all I did was press the bolt head against the hull with one finger while tightening the nut on the inside, and still I generated enough tension in the bolt to completely countersink a one-inch washer into the outside surface of the hull. The slight friction of the bolt head against the washer was all it took to keep it from spinning, and Royalex is such a soft, crushable material that you don't want to make it very tight at all).
Anyway, a bolt that's the same diameter as the pop rivets that Wenonah supplies with their footbraces will have a head that only protrudes about 1/16th of an inch even before grinding. I really don't think most people would be too bothered by that.
Works well for me in many boats
All materials from Lowes or Home Depot
- Aluminun channel rivited or bolted through the canoe sides. One piece on each side about twelve inches long
- Holes drilled about one inch apart along the base of the channels.
- two pieces of aluminum tubing one slight larger in diameter then the other so one slides into the other, (check on some old lawn chairs to get out cheap)
- drill a bolt hole in each end, and then use a stainless bolt with a wing nut
- Adjust length as required
Cheers,
and Happy New Year,
JackL