Jon Boat Transom replacement - fasteners?

G26

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Jun 9, 2005
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I need to replace a rotten transom on my 12ft jon. I don't own a rivet gun, so would like to replace the rivets with some sort of bolts. The rivets that will have to be replaced are, for the most part, above the waterline. However, with a small jon boat there is really no part of the hull that *isn't* under the waterline at some point!<br /><br />Are there some sort of waterproof washers or something of the sort that are commonly used for this? What type of bolt would be the best? Of course it would be stainless...<br /><br />Thanks,<br />Brian
 

snapperbait

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Re: Jon Boat Transom replacement - fasteners?

On something like that I'd use 1/4"-20 and/or 5/16"-18 bolts, with fender washers to back up the nuts...<br /><br />Seal the bolt holes with 3M 5200 or some other sealant that's for use below the waterline.. In a pinch, there are some silicones and sealants for gutters that'll work just fine... Lay a thick bead of sealant around the hole, insert the bolt, slide a washer in place, thread the nut and tightent it down untill tight... Clean up the excess sealant that spoooos out from around the washers and bolt heads.
 

G26

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Re: Jon Boat Transom replacement - fasteners?

Good deal. Thanks for the input.<br /><br />Regarding material for the transom.... I only need a piece of plywood about 8 inches tall by about 4 ft long. I'd have to buy a whole sheet of PT ply, which is expensive. I need to use regular plywood, if possible.<br /><br />Would coating regular ply with lots of layers of urethane seal it well enough to protect from rot? I could seal the mounting holes before mounting it, even. It would look really nice, if nothing else. I would think urethane would protect it from moisture, but maybe some sort of Thompon's Water Seal would be better?<br /><br />Brian
 

snapperbait

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Re: Jon Boat Transom replacement - fasteners?

If using regular plywood, I'd use several coats of thin epoxy to seal the wood up, paying particular attention to the edges.. <br /><br />Then I'd paint the epoxy coated wood with something to protect the epoxy from UV rays...<br /><br />Now, that said, the cost of enuff epoxy to do the job plus the cost of half sheet of plywood would be about equil to buying a sheet of PT plywood..<br /><br />I dunno if urethane or paint would do much to protect from rot.. Might not help, but it could'nt hurt... :cool: <br /><br />Another thought would be to use a piece of pressure treated lumber, like a 2" x 10"... I've gone that route with good results..
 

G26

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Re: Jon Boat Transom replacement - fasteners?

I like the 2x10 idea... glad I thought of it. :)<br />That'll be much cheaper than ply. I'm not sure of the thickness... the way things go for me sometimes, it'll be 1 1/4" thick.<br /><br />I'll measure it this weekend and do what I have to do. Thanks for the advice.<br /><br />Brian
 

warekl

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Jul 6, 2005
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Re: Jon Boat Transom replacement - fasteners?

I'm doing the same thing. I went to Menards and bought a 2'x4' peice of 1/2' acx plywood for $9.00. (they sell small sheets) Cut out 2 pieces and used Gorilla Glue $7.00 to laminate up it to 1" then used some stainles steel screws $2.00 to screw the two together. Use exterior Polyurethane $10.00 qt and give 3 coats.<br />Paint over the polyurethane to protect from uv and the transom should last many years. I used stainless steel screws and washers with self locking nuts $15.00 and Aquaseal $2.00. This procedure was recommended by a custom boat shop...<br />Good luck
 

Winger Ed.

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Mar 24, 2004
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Re: Jon Boat Transom replacement - fasteners?

The last one I did, I just humped up and bought a sheet of the green pressure treated 3/4" plywood, and made the transom board double thickness. <br /><br />Figuring your time is worth 9 cents an hour---- it works about the same with the savings from regular ply. and putting on the coatings.<br /><br />Instead of rivets, as metioned, use 1/4 or even 3/16ths stainless bolts, Stainless locknuts, & the large Stainless fender washers mopped down with plenty of silicone. <br /><br />The last jon-boat I did a transom replacement on was a 14'er with a 18 horse hanging off the back of it. That was over 10 years ago, and its still doing fine.
 

G26

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Re: Jon Boat Transom replacement - fasteners?

Originally posted by KLW2:<br /> I'm doing the same thing. I went to Menards and bought a 2'x4' peice of 1/2' acx plywood for $9.00. (they sell small sheets) Cut out 2 pieces and used Gorilla Glue $7.00 to laminate up it to 1" then used some stainles steel screws $2.00 to screw the two together.
That's more or less what I went with. I used PT 1/2 greenboard, laminated to make 1". Fit perfectly under the aluminum lip across the back of the transom. Used liquid nails to laminate them because I had some on hand, and didn't coat it with anything. I figure if it lasts 3 or 4 years, I'll be happy. I probably won't own it that long anyway - need something a little bigger.<br /><br />Thanks for all of your suggestions, everyone. It was a great help, and the transom is rock solid.<br /><br />Brian
 

Beck

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Feb 24, 2004
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Re: Jon Boat Transom replacement - fasteners?

G26,<br /><br />I replaced the transom on 2 all. boats. Had to glue two pieces to get the right thickness. Once had to router out for three transom braces, miscalculation I guess. <br /><br />But anyway I have replaced many rivets on my current flat, I used 1/4" x 1" stainless steel carriage bolts and coated the heads with 5200. This works very well. I also used lock washers with lock nuts (nylon piece in nut to prevent it comming loose).<br /><br />Beck
 

Beck

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Feb 24, 2004
Messages
165
Re: Jon Boat Transom replacement - fasteners?

G26,<br /><br />I replaced the transom on 2 all. boats. Had to glue two pieces to get the right thickness. Once had to router out for three transom braces, miscalculation I guess. <br /><br />But anyway I have replaced many rivets on my current flat, I used 1/4" x 1" stainless steel carriage bolts and coated the heads with 5200. This works very well. I also used lock washers with lock nuts (nylon piece in nut to prevent it comming loose).<br /><br />Beck
 
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