Long time lurker but this is my first post here. On my most recent build I glued walnut cleats to the sides with thickened epoxy to mount my seats to instead of the traditional method of hanging them from the gunwales. They have survived several day trips, but I am having second thoughts about their long term durability. Anyone ever used this method and do you think they will hold up? Thanks
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Happy D.B. Cooper Day (1971)! ✈️💵🪂
Seat mounting
- Thread starter Merlin
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I've done the same. I know that Stripperguy has as well. He once glued up some test pieces and took them to work to measure how strong they were. If I remember correctly it took 300 pounds of force to break off a small piece of mahogany. You should be fine.
Alan
Alan
It's a great method, especially if you know how low you want your seat. Lowering later will be some work.
If your gunnels are soft wood, it would be a great option
OH ! Welcome aboard ! Always great to see some new views. Oh and pics too !
Jim
If your gunnels are soft wood, it would be a great option
OH ! Welcome aboard ! Always great to see some new views. Oh and pics too !
Jim
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Hi Merlin. The cleat will be plenty strong as the load is mostly shear. Peel loads will be introduced as the cleat is torqued when the seat is flexed.
As Jim said, an issue arises when you want to move the seat-- it's easy raising it because you can shim it, but lowering the seat requires more thought. I don't move my seats much these days, but there was a time when I changed them a lot-- mostly upwards; my seat is pretty much at the gunwales now.
As Jim said, an issue arises when you want to move the seat-- it's easy raising it because you can shim it, but lowering the seat requires more thought. I don't move my seats much these days, but there was a time when I changed them a lot-- mostly upwards; my seat is pretty much at the gunwales now.
For those of you that may have missed it, here are the photos and a plot to show the single shear seat cleat test. It was tested to failure at over 300 lbs load. The Cabosil thickened epoxy joint held fast, the failure was limited to the mahogany itself.
I specifically applied the load at a similar location to where a seat frame would likely contact the cleat.
For those that need guidance to read the plot, the major axis is the applied load and the minor axis is the resulting deflection. Note that the delta deflection is all that matters, the starting point is an arbitrary value.
The load was applied initially from 2 lbs to 150 lbs, then cycled back to 2 lbs, so you see the small hysteresis loop.
Next, the load was increased from 2 lbs to 200lbs, you can see the resulting deflection as I dwelled at 200 lbs. This is actual yielding of the mahogany.
Finally, load was increased from 200 lbs to 325 lbs, and cycled back to 2 lbs, that's the large hysteresis loop.
I specifically applied the load at a similar location to where a seat frame would likely contact the cleat.
For those that need guidance to read the plot, the major axis is the applied load and the minor axis is the resulting deflection. Note that the delta deflection is all that matters, the starting point is an arbitrary value.
The load was applied initially from 2 lbs to 150 lbs, then cycled back to 2 lbs, so you see the small hysteresis loop.
Next, the load was increased from 2 lbs to 200lbs, you can see the resulting deflection as I dwelled at 200 lbs. This is actual yielding of the mahogany.
Finally, load was increased from 200 lbs to 325 lbs, and cycled back to 2 lbs, that's the large hysteresis loop.
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Very impressive! Good work.
BTW, the sample cleat used in that testing was the same as I put in several tandem boats. It was 3" lg x 3/4" ht, for a total surface area of 2.25 sq in
