Need advice on what to use to fill and seal seam on lower transom

[billybarue]

Did a float test on the boat yesterday and after about 10 to 15 mins in the water there was about 4 inches of water in the boat. pulled boat out of water and watched where the water was escaping. It was primarily coming out the bottom seam where the transom meets the bottom of the boat. I removed the paint at the seam and found what looked like bondo. I cleaned out the locations that need attention. The previous owner filled most of the seam on the bottom of transom and about 12 inches up each side with white filler I was told was bondo. I need to know what I should use to fill and seal these compromised spots. Should I be using epoxy or should I use the 3M 5200 caulk? For epoxy applications it was recommended I use WEST system epoxy and for an application where you don't want to use epoxy i was told to use the 3M 5200. I don't know what I should be using around the transom.

[nedL]

We need some more information for a complete answer. What kind of boat, how big, what type of construction are good starters.

Certainly not very big for that depth of water in a few minutes, Maybe plywood construction??

[billybarue]

it is a 63 grady white, 17 foot, lapstrake design

[Peerie Maa]

Pictures would help if you can. They'll give us an idea of the amount of gapping, whether the fastenings are suspect etc.

[Thorne]

For a 'quick n' dirty' fix 3M 4300 might be OK although removing it will be a hassle, 5200 is a bad idea as it is more of a glue than sealant, is extremely difficult to remove and often takes the wood along with it.

As above more info and photos would be a big help.

[billybarue]

the gapping on the sides of the transom where the boards should be flush and attached at the widest point is about 1/4 inch maybe a little more. I will get some good pictures later.

[wizbang 13]

I think this is a plywood boat. Bondo is wrong. Any bondo should be pulled out. You can identify it by scratch n sniff. Some like 5200 and some like Epoxy. I go WEST.Is the transom of the boat getting punished by sitting on the trailer poorly? Transom supported on wide wood bunks, not rollers? Pics?

[billybarue]

keel is supported on rollers and the transom is sitting on 3" inch wide bunks that are about 4 feet long.

[Peerie Maa]

the gapping on the sides of the transom where the boards should be flush and attached at the widest point is about 1/4 inch maybe a little more. I will get some good pictures later.

1/4 inch most probably needs refastened, possibly with fashion pieces inside the end grain of the transom where the nails wont hold so well.

[billybarue]

trying to upload pics now..

[billybarue]

[billybarue]

[billybarue]

hope i did that correctly...the gap in the other side is about the same and on the bottom of the transom the gap is smaller and not as long.

[billybarue]

[billybarue]

[mackaye]

That looks rather serious to me. I'm no great expert, but it looks like the wood has pulled away from the fasteners. Take a pick to the wood and see if you have rot issues. As a fast, cheap, and dirty fix you might try to refasten and glue it down with epoxy or possibly PL Premium - as long as you can get some tight clamping pressure and the wood is sound. If you can't get a tight joint, you could fill the open area with a fiberglass paste. But this wouldn't be a long term fix. I suspect you need much more extensive work than just refilling the open areas with a different type of filler. There are tons of guys on this forum that really know their stuff. I'm sure they'll chime in. Good luck.

[RodB]

I guess many approaches would work here... but EPOXY is the adhesive of choice IMHO.

First, it sure looks like you've got some rot to deal with. ... cleaning and scraping will show you more.

Looks like you need to do lots of cleanup of all joint surfaces in the entire joint, getting rid of all the gunk (in and around the joint)... Clean all to bare sanded wood. Once the major cleanup is accomplished, you can really evaluate what you have to work with. You will hve to begin the refit of the entire joint adding wood if necessary ie... closing up the joint to a much better fit.

You can use some blocks of wood that are screwed to the transom in key locations... then pull the bottom of the hull up to the blocks with more screws from outside the hull bottom and sides. Do this over the entire gap to get a nice tight fit.

Once the transom joint is stabilized/secured with the blocks and screws... then bond the joint from the outside with thickened epoxy in the joint... followed with fiberglass tape (3" and 4" 9 oz tape simultaneously wraps nicer than biaxial) or biaxial tape. Be sure to form a nice radius on the exterior corners of the transom/hull joint so the biaxial tape will wrap nicely to the exterior joint surface.

Lastly, remove the blocks on the inside of the hull and bond/fillet the interior of the transom/hull joint followed with biaxial tape.

Once cured, scrape, sand, fill, and fair all. This will result in a strongly bonded transom with all gaps filled with thickened epoxy. Thickened epoxy will make up for any shortcomings you may have in joinery of the transom and hull.

You may have some areas of partially rotted wood that will have to be dealt with during this process. CPES can help here... or you may have to scarf in some replacements pieces. You need to be sure that the transom and the stern panels edges of the bottom and sides are all structurally sound. The procedure described above assumes you will remove and structurally repair any deteriorated areas. There are many methods to do this with epoxy.

Good luck,

RodB

Edited to add... I don't know how sound the transom is, but I wouldn't hesitate a minute to replace the entire transom if it were structrually compromised at all.

R

[Peerie Maa]

It looks as though the nails have drawn from the end grain wood of the transom as I suspected may be the case.
When you have finished the clean up as advised by RodB, I'd try to ease out the fastenings that have let go. Then I would try putting a webbing tie down strap around the stern, and see if you can wind the planks back into contact. I am concerned that with them all standing off so much, the joints between the streaks have spread slightly so that the skin now has a slightly greater circumference than before. By pulling them back in, with a Spanish windlass, you will find refastening easier, 'cos you will not be trying to pull each plank sideways as well as in.

[billybarue]

sounds like a job for a professional because i don't think I have the correct tools or skill set to accomplish this task properly. I have a local boat builder I can bring it to and hopefully he will have time to work on this project otherwise I'm going to be need lots of input and assistance here. Thanks for the input thus far, it's much appreciated.

[wizbang 13]

1000 ways to fix that.Where are you BB,looks like ice damage. Clean it, open it,dry it, post more pics. One thing I would not do is put fg cloth/tape on it. These type of boats are weak in terms of keeping their shape on a trailer. The slightest "hook" in the bottom will result in dangerous handeling at planning speeds. So, for starters, if you can't bring those planks down where they belong,she will porpoise too much and steer hard.

[RodB]

Wizbang... If this is a plywood boat as you commented.... would you trust epoxy fillets alone without any fiberglass tape? ... at a minimum on the inside? Its not that difficult to fair an external layer of 9 oz fiberglass tape and if necessary, you could bring down the strake ends say the lastt 4-5 inchs at the transom a bit so that after taping the last few inches of the sides and bottom would be straight and fair. I would think the fiberglass adds lots of strength to the epoxy joint.

I'm wondering what the original construction was on this boat as far as bonding the hull to the transom... fasteners and adhesive ???

RodB