Primary Reason Starcraft Transoms Turn Into Mulch (My Opinion)

[bunnymoney]

Of course it's water intrusion into the plywood.

Just looking at the Starcraft transom area you might never guess there is a problem lurking right in front of you.

The transoms, for the most part, have nice aluminum channel caps that run the full width. The gunwales have real nice caps that finish off the corners.

This is where the real trouble resides.

First pic shows end cap overlapping channel cap:



Second pic shows end cap overlapping gunwale(green and out of focus)



Some of my green paint is chipping at this joint and needs to be repaired and sealed to prevent water from going under the cap and racing to the end of the gunwale and dumping right on top of the transom. Then when there is no more room for the water it runs down the top of the transom under the channel cap toward the motor.


I believe this overlap is the primary source of water intrusion and should be sealed.




Obviously you can't neglect holes, screws, and rivets in the transom itself.

If you stare at the pics of destroyed transoms you may come to the same conclusion as I.

 

[laurentide]

Yes, that seam definitely needs to be sealed. I had water intrusion there, and when combined with a less than perfect plywood edge seal and low quality ply (all my fault), I now have minor delamination on one side and I have to re-do my transom. This is a good issue to point out, especially if your boat gets rained on once in a while.

 

[jbcurt00]

Simply painting the transom wood, originally, from the factory, and a splashwell design that leaves the paint wood exposed to the elements IN A SPLASHWELL, is a much bigger problem, IMO, then water off the gunwales.

But, yep, many production boats, both tin and glass, could benefit from better attention to detail and etc on many facets of a boat. Of course that might drive new boat prices higher.....

Yikes, price a new 17 or 18ft bowrider. Ouch....

Hence the guys hanging around the Starcraft dry dock at Iboats. Fixing older stuff to better then 'new' condition.

 

[laurentide]

Jb, the reason it's an issue, at least for me, is that I took the time to seal the exposed wood above the splash well, but neglected to seal that seam. So, when combined with my less-than-great plywood edge seal, that's what caused my damage over a couple of seasons. It would've been easy to prevent had I simply thought of it. It'll be a lesson learned when I do transom 2.0 with marine ply and fiberglass cloth and epoxy (something I wish I'd done with all the wood).

 

[DLNorth]

What do you expect the glass/resin to do for you?
If might be worth some time over on the Woodenboat BB to see what their experience with it is.

And with all the trouble with regular ply in a boat, why do guys keep using it? Why don't more use MDO/HDO?
a product designed to be in the weather and totally waterproof.

Dan


"fiberglass cloth and epoxy"

 

[gm280]

The real problem isn't so much water getting in, but water getting out. Water will find any little crack or area that it can wick into. But then it doesn't dry out or run out. And that is where the rot problem begins. And since the owner/operator can't see it, the problem grows until transom (or floor, stringers) rots. And once the owner/operator finely is privy of the rot, it is too later to save. As with most anything, prevention is the key to longevity. Wicking capillary action of cellulose fibers is really amazing to see. JMHO

 

[bunnymoney]

DLNorth: Please post or "write out" a link to "Woodenboat BB". I would like to visit there.

I have however found specs from APA for MDO/HDO and frankly was not impressed. Spec for HDO with sealed edges is less than10g per square foot over 48 hours. Spec for MDO with sealed edges is less than 50g per square foot over 48 hours. That's 2 ounces of water per square foot over 2 days. The big deal about HDO/MDO seems to be the hot stamped foil that is applied to the big flat surfaces (not the edges) of various grades of plywood.

If your boat sits outside in the weather and not protected from water intrusion I don't see how MDO/HDO will save you.

I agree wholeheartedly with gm280. The actual destruction of the transom is caused by the intruded water not drying up and microbes eating the cellulose.


"After further review" of pictures of various rebuilds here I also can see that water gets between the plywood transom and the aluminum transom. I'm thinking this is mostly coming from the same area where the gunwales and end caps are dumping water onto the ply transom and some (maybe a lot) is wicking between the ply and aluminum.


I'll see if I can move some pictures from various rebuilds to this thread as examples.

 

[DLNorth]

http://forum.woodenboat.com/

you might have to do some searching but keeping water out of the wood used in a wooden boat generates a lot of discussion (and opinions) there.
The basic consensus IIRC is that ultimately no matter how well sealed, the water gets in.


This has to be a lot better resistance then std ply.

"Spec for HDO with sealed edges is less than 10 g per square foot over 48 hours. Spec for MDO with sealed edges is less than 50 g per square foot over 48 hours. That's 2 ounces of water per square foot over 2 days."

 

[Watermann]

Leaving the boat out in the elements uncovered to be destroyed due to laziness is the reason any boat goes to pot and becomes a rot bucket.

The 79 V5 SS I'm working on now has 2 sheets of AL covering the top of the transom wood, the gunnels and then the splashwell wings over them. I filled every hint of a void with 5200 on the top of the transom wood and it was given 3 coats of oil base alkyd industrial paint over a coat of the same primer. These 2 layers of AL extend out over the rub rail channel and are riveted on out over the sides of the boat so there is no way water could get to the top of the transom wood by way of the end caps. Once the SW went back on there is no wood exposed to the elements, it's all covered and the lowest point in the SW where the motor mounts has an attached one piece transom cover.

I think even if left to the elements it will outlive me as they did this boat right so not all SC boats are created equal.

 

[jbcurt00]

bunnymoney check your PMs