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Installing a foot brace in a balsa boat

Posted by 2trout 
Installing a foot brace in a balsa boat
May 30, 2020 11:51PM
While I have my boat upside down for repairs, I figured that i should finally install a foot brace in front of the rowers seat. Cant seem to find anything using the search engine or in the plans. Any ideas? (I have had to cut and remove two sizable areas of glass and core material due to wet core.)

trout
Re: Installing a foot brace in a balsa boat
May 31, 2020 12:10AM
If you could be satisfied with a fixed position foot brace just glue something down. Sand and clean it up and weight down a piece of wood with thickened resin.

If you want adjustable it gets more complicated. Problem solving rears its head. With Plascore I might cut out two Circular areas and bury a bolt in resin so just the threads poked up.
Re: Installing a foot brace in a balsa boat
May 31, 2020 02:10AM
Maybe just glue down a wood slab with bolts poking up?
Re: Installing a foot brace in a balsa boat
May 31, 2020 10:07AM
That would work. I'll stew on it.
Re: Installing a foot brace in a balsa boat
June 01, 2020 11:03PM
Working on a similar project. I've purchased for $5 a piece 12" samples of Trex Decking. Ordered from Trex directly. Look for the solid boards.
Great because they're cheap to ship, don't have issues with trying to get a long board shipped. Will cut to fit, resin down to plascore floor. These could be notched for a horizontal foot brace, or could be use to screw down into.
Re: Installing a foot brace in a balsa boat
June 02, 2020 12:36AM
Like that approach
Re: Installing a foot brace in a balsa boat
June 03, 2020 12:43PM
Sounds interesting.
Re: Installing a foot brace in a balsa boat
June 07, 2020 01:03AM
To attach accessories to the boat bottom, like foot anchor release, foot braces, anchor rope fairlead, and the like, I epoxy plywood blocks that have tapped threads to the bottom of the boat. Cut the size block you need, over drill a hole, fill with structural epoxy (fillet or jb weld, etc), drill pilot hole, tap threads in structural epoxy. Finish and fair block and epoxy to the boat bottom. No need for clamping, just get a snug fit. Attach accessories with machine screws or bolts.

To finish the blocks I put a single layer of 4 or 6 oz glass on the top, sand all the edges to remove sharp edges, saturate the edges with laminating epoxy, fair, and then glue down.

Once the blocks are glued down, fair the edge that is adjacent to the boat bottom.....add glass along the side and onto the bottom if you wish.....paint....go fish.






Re: Installing a foot brace in a balsa boat
June 07, 2020 11:11AM
Think about using Trex decking boards instead of wood. Trex does not soak up water.
Re: Installing a foot brace in a balsa boat
June 07, 2020 09:06PM
I like this idea Eric!

The tapped threads into the structural epoxy are strong enough that when my feet are on the foot brace and I suddenly need to reef on the oars hard, a bunch of times, the brace will stay put?

trout
Re: Installing a foot brace in a balsa boat
June 08, 2020 10:26PM
I'm not an engineer so cannot provide an analytical response to the question of thread strength. From practical experience running class III and IV rapids in my dory, I have no undue concerns about a foot brace tearing out.

I decided to use a threaded epoxy plug rather than a threaded metal insert or using a wood screw and then wetting the hole with epoxy and then putting the wood screw back in to seat and seal the wood screw threads. I am under the impression that machine screws have better holding strength than wood screws.....but I cannot remember why I think that!

The epoxy plug reduces the chance of water getting into the plywood anchor pad. The plywood anchor pad means the boat bottom is not serving as the accessory anchor. If the anchor ever rotted or failed or needed to be moved, it could be without disturbing the bottom panel lamination.

Sandy suggests using Trex because it will have even better resistance to water. I am unsure of anchor strength - either direct wood screw, threaded metal insert, or epoxy plug - in Trek. I also have no idea about bonding Trek to the boat bottom panel. The option of using Trek is worth considering.
Re: Installing a foot brace in a balsa boat
June 10, 2020 01:40AM
Eric, I wonder if machine screws have more strength than wood screws because the shank is not tapered. It seems that the consistent diameter would provide more resistance to pulling out than an increasingly smaller screw.

Rick N
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