Advice on replacing transom wood in aluminum fishing boat

Jfoutch · Jul 18, 2013

I have an old Crestliner aluminum fishing boat that I sort of inherited from my family. It was my great grandfathers and hasn't been used in years. I dug it out of storage the other day to see what would be involved in getting it back on the water. I am not experienced with fixing and working on boats but am a DIY type of person and am gonna try to replace the wood where the outboard motor is hung on the back.

The wood was severely rotted so I removed it all. There are 2 pieces. One was a 1/2 inch plywood that went on the outside and the other was a 1 inch piece of wood on the inside of the boat that I couldn't recognize it was so rotted but it looked like a hardwood of some type. I was hoping I could just use 2 pieces of 3/4 inch marine grade plywood, so I'd only have to buy one type of wood, then coat it with some type of epoxy before putting it back on the boat. I am looking for some advice on the wood and epoxy I should use or maybe a link to a guide. Thanks a lot!

ThrottleBack · Jul 18, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

I can't offer much but since it is aluminum if you don't get marine grade just make sure you do not get treated wood, it will eat at the aluminum.

Mr. Asa · Jul 18, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

The previous owner of my boat replaced the wood on the transom with the plastic "wood" they use for decks and such. It should effectively last forever.
I can take some pics if you want, but if you can find some I'd use that stuff.

Bob_VT · Jul 18, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

I will move this to the restoration section.

Do not use any pressure treated wood since the copper reacts with aluminum.

Do not use engineered decking wood since it is not rated for the stress and is too flexible. That issue has been discussed here before.

You can save some money and use exterior plywood and epoxy or polyester resin. It will last just another 30 years or so

Jfoutch · Jul 18, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

Hey thanks for the replies! Sorry about the wrong section I misses the restoration section. Ok I think I will just use an exterior plywood and treat it myself since I already have some. This boat will probably be used lightly and stored inside anyways. Can anyone link me to the proper epoxy or resin to use for such a project? Would there need to be anything in between the wood and aluminum? Thanks

64osby · Jul 18, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

J- Welcome to the site.:joyous:

Lots of Tinny's here. Lots of good advice, like Bob's above (and TH's)

Do the knee braces attach to the transom wood in any way? If not you can do just about anything you want.

I did a transom last year and used Spar Varnish to seal it. Works good and should last many many years. It's not quite as durable as epoxy, but works really good, less expense and easy to work with.

Keep asking questions and posting pictures and good luck.

jbcurt00 · Jul 18, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

If you use epoxy resin, it needs to be painted/spar varnished after. Epoxy isn't UV stable.

Great to keep the boat in the family!

Based on the pix, it looks like the wooden transom was on the outside only:

This doesn't look like it ever had a wooden transom:

Perhaps a small curved trim board where the hull is discolored, but not 'really' a transom per se.

What motor did your grandfather run on it? Still have it w/ the boat?

Welcome to the dry dock.

Jfoutch · Jul 18, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

jbcurt00 said:
If you use epoxy resin, it needs to be painted/spar varnished after. Epoxy isn't UV stable.

Great to keep the boat in the family!

Based on the pix, it looks like the wooden transom was on the outside only:

This doesn't look like it ever had a wooden transom:

Perhaps a small curved trim board where the hull is discolored, but not 'really' a transom per se.

What motor did your grandfather run on it? Still have it w/ the boat?

Welcome to the dry dock.

Yes on the inside there was just a small piece of wood, maybe about an inch thick. The motor is a 1969 20hp Johnson and I'm hoping it will still run. I know it was tuned up and ran fine about 10 years ago but has just been in storage ever since then.

fishrdan · Jul 18, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

If you need 1/2" and 1" plywood, use a sheet of 1/2" plywood and laminate 2 pieces together to get the 1" thickness.

Buy "5-ply" 1/2" plywood as it's built much better, it's stiffer and more rigid than cheap 3 ply 1/2" plywood.

jbcurt00 · Jul 19, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

You should have NO problem getting the '69 Johnson up & running if it was in good running order when it was put away. There is a really good engine forum @iboats too, so start a thread there if you run into any trouble or have questions.

Any combination of inner & outer wood to get you to 1.5" will do nicely. More lams the better as Dan mentioned. Exterior grade, or other plywood made w/ waterproof adhesive: Aruaco (sp?) is great, but can be hard to find, and MDO or ACX are also good choices.

Jfoutch · Jul 19, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

jbcurt00 said:
You should have NO problem getting the '69 Johnson up & running if it was in good running order when it was put away. There is a really good engine forum @iboats too, so start a thread there if you run into any trouble or have questions.

Any combination of inner & outer wood to get you to 1.5" will do nicely. More lams the better as Dan mentioned. Exterior grade, or other plywood made w/ waterproof adhesive: Aruaco (sp?) is great, but can be hard to find, and MDO or ACX are also good choices.

I hope you're right about the motor. While it never sat out in the weather, it was in non-temp controlled storage for about a year so I hope that didn't mess anything up. I'm gonna go by Lowe's today and pick up a piece of wood and some varnish or epoxy of some type and get started!

The boat itself was fixed up from top to bottom at my grandfathers request before he died. Of course it was never even used one time after this and sat outside in the weeds for a couple years before being moved into my warehouse. I'm gonna see if I can bring it back to life, I know there were a lot of memories made on that boat.

kfa4303 · Jul 19, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

HI J. Here are some great links to help you get the motor up and running again. You can get any routine parts you may need like carb kits, impellers, points & condensers, etc...right here at iboats for about $20 each. Be sure you only ever run the motor in a test tank while using 50:1 mix and Champion J4C or J6C spark plugs.

1969 Johnson 20R69D 20 hp Outboard Motor Parts

Maintaining Johnson E & FD Serie

Jfoutch · Jul 23, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

When I am replacing the wood, should I use some type of marine caulk in the screw holes of the aluminum? Or just screw the wood directly to the metal.

ezmobee · Jul 23, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

Seal the holes with 3M 5200 or 4200.

kfa4303 · Jul 23, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

+1. You should be able to get the 3M 5200 or 4200 from most Lowes/HD. If they don't have it West Marine, or any other boating store will.

Jfoutch · Jul 23, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

I ordered a tube from Amazon for about $10. Ace hardware didn't carry it and I was just in Lowes and didn't feel like going back in. Should I just apply some to the threads on the screws and then maybe get some big flat washers and apply under them as well?

kfa4303 · Jul 24, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

yup, you got it. I just apply the 5200 to the bolts like mustard on a hot dog, then insert them into place. Using some nice, large washers will help too. Just make sure everything is stainless steel so it will be super strong and never rust.

fishrdan · Jul 24, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

5200 is some gooey/sticky stuff, so make sure to have plenty of paper towels and some paint thinner to clean off the excess that squishes out from the bolts. I cut the paper towels into little 2"x4" pieces, so I'm always using a clean piece of paper towel.

Jfoutch · Jul 25, 2013

Re: Advice on replacing transom wood in aluminum fishing boat

OK thanks this is good stuff. I should be getting the 3m and a new plug in the mail today. I took the motor to a shop earlier in the week and hope to hear back soon on it.
The trailer is gonna need some work as well like tires, lights, coupler, etc. Also the wiring to the bow light is super old and I'll probably replace that as well. The switch is rusted in place so that's gotta be replaced too. Then I'll have to get a battery, replace the wood one one of the seats, and hopefully if I'm lucky it won't have any leaks.
Its crazy how much needs to be done to a neglected boat, even a simple little aluminum one like this. I see these pictures of people replacing floors and stringers in glass boats and consider myself lucky though.

Advice on replacing transom wood in aluminum fishing boat

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