Attaching splash well back to transom

[redlinj]

After 4 days of off and on work I was finally able to remove the rotten wood in the transom of my 21' sylvan super sporster. Contorting myself to remove all the screws and bolts was the easy part. The rotted wood ply was sandwiched in between 2 layers of aluminum and was so swollen it wouldn't budge even when I screwed in large eye screws and pulled up with my engine lift. The whole stern lifted off the trailer. Ended up buying an electric chain saw from harbor freight! I pretty much know from all the research i have done on iboats how I am going to replace the transom and what ply I will use. The boat is rated for 200hp, and I am running a evinrude 150 with a weight of around 375lbs. What I would like are some opinions on whether I should go with stainless bolts rather than the inch long screws that attached the splash well to the transom. Maybe it is overkill but bolts won't pull out like the screws did. Also, I plan on filling all bolt/screw holes with peanut butter unless the consensus rules for 5200 or the like. Thanks!

 

[jbcurt00]

You know how much we love pix.

Got any before and after plywood transom removal? Or of the splashwell?

 

[Georgesalmon]

Peanut butter will crack over time because its so hard. 5200 will stay a bit flexible and I would vote for that. I am also a big fan of SS bolts for anything structural.

 

[GA_Boater]

What I would like are some opinions on whether I should go with stainless bolts rather than the inch long screws that attached the splash well to the transom

Drilling 487 (boy, they use a lot) of holes in the transom skin isn't going to prevent rot. In fact it will promote rot because over time one or more of them will develop a leak. It's all about odds. Stay with the screws and keep the transom skin as intact as possible.

The reason the screws pulled out is because the wood rotted. On my oldie, the sealant used to seal the splashwell/transom joint dried out and cracked. Any water getting into the well either went out the drains sorta or seeped through the joint and right on those screws. When you reattach the splashwell, use 5200, a more durable choice.

One use of PB filler is for the through bolts. Where a hole is drilled in the wood for a bolt, instead of making a 3/8" hole, make it 1/2". Fill the hole with PB, smooth it and re-drill to 3/8". That way the bolts have no wood contact and with liberal use of 5200, chances of rot are minimized. You must use backing plates larger than the PB plug so the plug isn't pulled out if the wood isn't sandwiched with metal..

As stated above, got any pics?

 

[redlinj]

Originally there were 72 screws holding the transom and splash well together. The boat is an '88 so when the wood rotted, the 2 dozen or so screws directly below the motor pulled out leaving a pretty wide gap for water to enter the bilge. I'd certainly like to do the best job possible in waterproofing the screw/bolt holes as well as the plywood itself. I'd love to get some pics to you all. I tried last night for 3 hours but my efforts were a dismal failure! I even joined the Photobucket,-- I think! I will keep trying!

 

[Tnstratofam]

When I replaced the transom in our 16SS I sealed the edge between the splash well and the new transom with 5200. We've been using it for two seasons now, and other than re applying some at the very corners after the first month the 5200 has held up superbly. I also coated all the transom through hole fittings and screws with 5200, as well as the 10000 or so scerws Starcraft used to attach the splash well to the transom. I did replace all the screws and bolts with new ones from my local Fastenal with stainless steel.

Oh and I would just replace the screws with screws and not bolts. Keep the boat covered when not being used and seal the new transom wood correctly and it should last for a good 40 years or more. Improper wood sealing from the factory combined with leaving the boats out in the weather uncovered are the biggest reasons for rot in most boats.

 

[GA_Boater]

On Photobucket after the pics are uploaded, click the IMG code button when viewing a pic. Paste the code into your message.

 

[fhhuber]

I'm starting to think that improper covering may be worse than not covering...

Pulled the cover and opened my rear access hatch to the batteries/gas tank/bilge... and the hatch was dripping after 2 weeks under the cover with no rain and what looked like a dry bilge. Nose of the boat raised 2 ft vs the ball connecting to the truck's hitch. (and the driveway slopes down toward the stern.. so the bow is WAY high)

I'm looking for ways to ventilate under the cover.

 

[GA_Boater]

I'm starting to think that improper covering may be worse than not covering...

Pulled the cover and opened my rear access hatch to the batteries/gas tank/bilge... and the hatch was dripping after 2 weeks under the cover with no rain and what looked like a dry bilge. Nose of the boat raised 2 ft vs the ball connecting to the truck's hitch. (and the driveway slopes down toward the stern.. so the bow is WAY high)

I'm looking for ways to ventilate under the cover.

Then start a thread of your own. Clearly this is off topic. Thanks.

 

[oldboat1]

think the hardest part of the job is getting the old transom out of the envelope. drills, screwdrivers, chisels, chainsaws....

Agree with prev. posts re. use of 5200 for sealing when replacing motor well, and would use it for screw holes as well.

 

[redlinj]

Will the 5200 work ok also for thrubolts? One thing I forgot to mention, but don't know if it makes any difference to anyone is that after the rotted ply was removed, the inner skin came right out. Will make a good template for the new transom but unsure if it will cause any unforeseen hassles when putting everything back together! We'll see!

 

[GA_Boater]

5200 is perfect for through bolts and 4200 works as well.

It sounds like a PO may have replaced the transom and added the inner liner. I'm not 100% on that with a Sylvan.

Pics would help a lot.

 

[Watermann]

The Smokercraft of the late 80's or early 90's also have the inner sheet of AL.

No way would I ever drill all those SW holes clear through, nothing but trouble and not needed. SS and 5200 are a match match in heaven.

 

[oldboat1]

Guess this is more than called for in your post, but the new transom insert needs to be sealed as best you can, the edges in particular. I like epoxy, but calls for a lot of it. (Woodonglass has discussed a sealant of 1 qt. linseed oil, 2 qt. mineral spirits, 1 qt. spar varnish -- should be about the right amount to soak and seal a transom, and cheaper than epoxy.) In building the transom of 2 layers of 3/4 inch ply, can use 5200 and drywall screws, sealing the drywall screws with whatever coating your choose. For installing the new transom, I use 5200 around the perimeter -- have also used expanding foam once or twice. Make sure you seal the inside edges of the hole after drilling to reinstall the drain tube.

I'm flat out not familiar with the inner liner you describe. It sounds like factory installation had it freestanding (not adhering to the plywood insert), but not sure. Maybe the adhesion failed when the wood rotted. Does it slide into side flanges (maybe screwed in on the edges, through to the wood insert)? In any case, reinstallation of the wood insert may prove easier and better if you can install the insert before the inner liner. You would presumably be able to caulk and fill around the perimeter of the new wood more easily. Whatever the appropriate installation of the inner liner, I would completely seal the new transom wood before reassembly.

Good project.

 

[redlinj]

Fellow boaters, I REALLY appreciate your comments! The transom looks to be stock. It's even painted the same sylvan blue and the outer skin and corner end caps do not look tampered with. Waterman's concoction is interesting. How many coats??? If I go the epoxy route I will put at least 4 coats on. I will stick with ss screws for the splash well and coat each screw hole with 5200. Unfortunately, I will have about a dozen or so thru bolts to seal up. If I don't have to deal with pb and the 5200 works as it should, i think then, things should be a bit quicker and easier. After thinking about it, I don't think the removable inner skin will pose a problem. I will just seal, seal and seal again! Thanks!

 

[oldboat1]

think the sealing rule is to keep applying until the wood no longer absorbs -- which depends on type of wood, moisture content, temp.... My sense is that four coats of epoxy is probably a little excessive, but might be about right for a thinned oil and varnish seal.

[ed. If you get serious with epoxy, might consider buttering edges (epoxy thickened with sawdust).]

 

[redlinj]

Thank you for that input. Nothing is etched in stone!

 

[jbcurt00]

Most recommend and apply finish, no matter what finish, to the edges on every flat side coat. That way the most absorbant part of the plywood, the edges, get twice as many coats as the flat surface.

2 coats on both sides, 4 coats on the edges is typical for epoxy. 3 coats on both sides w spar is typical.

More may increase the thickness of whatever you're applying it to, which may or may not make any difference.

 

[redlinj]

Good to know. And more coats may make a difference but will have to mock everything back up to be sure things will fit. Was impossible to gage the thickness of the old swollen ply.