Transom Help! 1978 Jon Boat

[tornkvist]

Good day,

I am stuck for some assistance on what to do next. The welds on the end caps have broken loose, and i ended up taking the support bracket (well what was left of it) off and trimmed up alittle around the areas. I have read that you have to fabercate a new support bar, and (or) you can use L channels. What are the recommendations, or next steps that would be prefered. I am really wanting to get this boat back on the water, and was a gift to me when I left active duty service.

 

[FISTer]

Re: Transom Help! 1978 Jon Boat

Lots and lots of threads on www.tinboats.net for repairing the transoms on jon boats. Basically, you'll need a sheet of exterior plywood, NOT pressure treated. The chemicals in pressure treated wood will corrode the aluminum and eat it away. Measure how thick your wood will need to be on the boat. Get a thickness of plywood that equals what you need when doubled. Use cardboard/posterboard to make a template for the inside of the transom. Cut two pieces of the plywood and test fit them. Glue them together.(You'll have to research what glue to use, I can't remember off the top of my head) Seal the whole thing really well with spar eurethane. Bolt it inside the transom, sealing the bolt holes with 3M 5200 sealant. You could add some aluminum angle across the inside to strengthen it a little more, but the plywood should be more than enough after bolted in. Then have your top cap welded back on. As long as it the wood is sealed well, it will last for a long time.

Where you at in AR?

 

[Bob_VT]

Re: Transom Help! 1978 Jon Boat

Good day,

I am stuck for some assistance on what to do next. The welds on the end caps have broken loose, and i ended up taking the support bracket (well what was left of it) off and trimmed up alittle around the areas. I have read that you have to fabercate a new support bar, and (or) you can use L channels. What are the recommendations, or next steps that would be prefered. I am really wanting to get this boat back on the water, and was a gift to me when I left active duty service.

Welcome to iboats.

Thank you for your Service! (I am retired active duty too...... there are many of us here)

That transom is a piece of cake since it is almost 1/2 way done. Once you establish the wood inside the transom (Usually a glued together piece of 3/4" doubled up) and bolt it in using SS bolts.......... Then you can form your own transom cap from aluminum angle stock available at home depot or tractor supply. Once it is together it will be rock solid.

Here is some transom wood advice.........

Cheap but pretty
2 pieces of 3/4" exterior plywood (Never Pressure treated since the chemicals attack aluminum) and glue them together with clamps and gorilla glue over night. Cut the thick piece to proper size...... and apply 3-4 coats of exterior varnish (that's the pretty part)

a bit more money
Use fiberglass chopped strand mat and fiberglass resin to seal the wood you have glues and cut to size......

a bunch more money
Use epoxy for the gluing of the wood and coating with layers of fiberglass cloth then 3-4 coats of varnish since epoxy does not like sunlight.

When you bolt the wood...... every hole you drill needs to be coated and sealed with either epoxy or 3m5200 and use only stainless steel bolts.

The secret is to keep the plywood fully sealed up so water has no chance of penetrating.

The aluminum angle for the top is what I have used on a few including my own. No need to weld it at all.... a few bolts or screws will hold it fine. You are dealing with the cap and the transom wood is where the strength comes from.

I did one transom with 4 pieces of 3/8" exterior ply that was all laminated together with epoxy and then coated with varnish .....talk about overkill .....well I had the stuff on-hand....... and that will outlive me now.

 

[tornkvist]

Re: Transom Help! 1978 Jon Boat

Im about 30 miles from Jonesboro, little town called Caraway.


I do appriciate the help on here, and procedures. Sounds to be alot better than I had orgionally expected, considering last year when I replaced the transform I used a 1" piece of fencing material, and just drenched it with tompsons water sealant. Dont know much about tin boats, was in the Navy so going from steel to tin/aluminum kinda lost where I needed to go with this.


I orgionally though that the upper brace was used to help keep the boat from shifting around, so was looking for ideas on how to replace it but leave the caps.

its good to find a place with retired military, makes me feel more at home

 

[tornkvist]

Re: Transom Help! 1978 Jon Boat

here is more photos of what im looking at, as well as adding. only used 1/4" ply for the front, with aluminum angle iron for the front.

as for transom there is no support, that is why i was under the assumption that i needed to replace the top support since it was orgionalyl a single piece bent over the wood.

but again photos will show more of what i am looking at

 

[FISTer]

Re: Transom Help! 1978 Jon Boat

I'm not retired, but did spend 8 years in the Army with two tours in Iraq.

Considering that it is a small boat, and you probably won't have anything larger than a 20 or 25 horse motor on there, the transom will be more than strong enough to support the outboard.

You'll have a pretty nice boat once it's fixed up.

 

[Bob_VT]

Re: Transom Help! 1978 Jon Boat

I HIGHLY doubt that a 20-25 HP would be good for that small jon boat. It would be suicidal!!! Post the boats dimensions - Transom height, length, and width and we can get an accurate HP rating.

Did you remove a seat for you front deck? If so was there flotation under that seat???

Thompsons is okay but not a permanent solution at all. At a minimum you should varnish the wood with 3 coats to help it last.

The transom top metal can be aluminum angle and it you are creative........ you can get a longer piece and actually tie it into the corner's that are there.

For a smaller john boat .....the transom is actually designed to support only a smaller motor...... say a 9.9 HP or less .....so it is not built to a much higher standard


Side note..... FISTer thank you for your service.

 

[tornkvist]

Re: Transom Help! 1978 Jon Boat

Transom measures 1 1/2 ft x 3 1/2 ft (h x l) boat is just over 13 ft x 3 1/2 ft wide. Unfortunately it never had any more seats, so enclosed the front. Found it weird that they put the first seat so close to the bow, figured the middle.

Thanks fister, for the comment bout the boat , as well as your service
Also thank you Bob for your service as well

I have an 1976 evinrude 6 hp that was given to me with the boat as well, runs good but still needs work.

 

[Bob_VT]

Re: Transom Help! 1978 Jon Boat

Yup due to the narrow hull...... you are probably maxed out at 15 HP.

The transom repairs will be MORE than sound for your motor.....

 

[tornkvist]

Re: Transom Help! 1978 Jon Boat

Thank you guys for the help, really appriciate it. Going to get the supplies tomorrow, and try to get this project completed this week. I will defentaly take pictures as I go, incase I lose my bearing again. Also last question before i end up going something im not suppose to do, i thought about shooting foam in the gunrail of the boat (has a couple of slits for a homemade tidown which is cool, but dont need alot of holes. should i shot foam in there or just leave it alone ?

You guys have been a major help and it will defantly not go unnoticed! thanks alot!!