transom rebuild technique (continuation of "which resin")

[Pete 88 Venus]

Hey guys, thanks again for all the help in the other thread.
I've got a few more questions about how to go about this. I originally was gonna get some premade composite panels that were supposed to be real light and real strong, but all of the distributors for the stuff won't sell me one sheet. So now I am going back to plywood.

I am attaching a basic layout of what my transom looks like (whipped it up in AutoCad). The overall width of it is about 69" and the height at the tallest point is about 17", it is 2" thick between the original outer skin (which I left attached to the boat) and the splashwell (which I cut off). So 2" is the thickness I need to achieve between the layers of plywood the laminates in between and the laminates on the outside. It was originally constructed with 3 layers of 1/2" plywood and enough laminate between each and the outer skins to come up with the 2" width. I plan to do the same thing.

Each layer of glass needs to be 1/8" thick to end up with the 2" including the inner and outer skin. What should I use to build up to this thickness? Woven roven, mat? How much of what weight do you think I will need to come up with that thickness?

The "knees" were notched into the first 1/2" layer and I plan to do the same thing, except they used only one piece of 1/2", I plan to at least use 2 layers of 1/2" or maybe even 2 layers of 3/4".

I am able to layer up and laminate all three pieces for the transom out of the boat, where I will have the ability to park a car on them or something to press them together. Once that's together I could also attach the 2 center knees and still be able to get it in the boat. The outer knees will have to go on once the transom is back in. Then i will mix up some epoxy with some silica, spread it all over the inside of the skin and where the knees contact and press it all in. This sound like a good plan of attack?

Once in I will use some cloth? (biaxial 8oz. maybe?) to laminate it all in there

So that's my basic plan of attack. What do you all think? If somebody has some better ideas please let me know. I want this thing to be real strong and last at least as long as the original, which by the way is an 83 sleekcraft.

[Pete 88 Venus]

another view

[Pete 88 Venus]

the layers

[TUG]

If the outer layer is still there, you will need to have 1 3/4"ply in the middle with 1/2 glued to each side of the 3/4" ! Glue it together with 1 layer of Mat inbetween! Glue it to the shell with 1 layer of mat and 1 layer of mat on the inside of transom with 1 or 2 layers of roven on top of that and that should do it ! That should be close to what it was before ! ........ Oh you probably already know but rouf it up with 24 grit to raise the fibers in the existing glass! Rouf it up good! I also rouf my wood up too but be sure you get the dust off before glueing it, TUG

[H2Onut]

Again, more than one way to skin a cat, I am using epoxy transom cast. with 1/4 inch ply against the outer shell, 3/8 kleg 75 for the inside, 1 inch seperation filled with transom cast EPOXY system. mix equal parts. pour into form, vibrate with a sander (to settle it) 4 hours later new transom.

Bi-axial galss with epoxy = strength of 1/2 inch plywood. Can do 3/4 marine ply in 3 layers also, but use the biaxial in between. You have a good idea, Should turn out real nice.

Thats whats so nice about fiberglass mfg/store being 2 miles away, they have several samples there showing the different laminate material and epoxies. Seeing is believing.

Transom cast epoxy, wont sag, warp, absorb water, crack, peel , or become a host for rot or any of ther other hitches that go with straight wood transom. Not cheap 70.00 for 2 gal kit mixed 1:1.

[Pete 88 Venus]

Here's some shots I took tonight. Tommorow is looking to be one itchy day, getting all that crap outta there.

[Pete 88 Venus]

2

[Pete 88 Venus]

3

[Pete 88 Venus]

why it happened:eek:

[H2Onut]

Tomorrows work

[Techno]

Did someone use it as target practice?
If you can the only thing I would change is to extend the knees all the way up as high on the transom as you can. I guess your putting the well back in?
I don't see any function they do other than take up internal space & hold water.

I would question the notching. If your reducing the true transom thickness don't do it because plywood doesn't gain much in this type of joint. A little bit works about as well as a deep notch.
The Knee fits into a dado or groove? This is only a side force thing, your trying to support the transom plate mostly. By cutting into it your actually making it weaker. The deeper you go the less transom thickness you have.

I would base the transom layup on the total wood needs. Knees and transom laid out to get what you need out of so many sheets, more than the thickness of them. You could do 4-1/2" layers but if this threw off the other parts it would be more $$
If your gluing plywood to plywood and using epoxy wet out both pieces and then put on a slightly thickened layer of epoxy and clamp those together. You can use screws near the center. You can also add the next layer after the first has set up. You don't have to do the whole thing all at once. Make sure its getting clamped up flat, otherwise it won't come out flat. Don't need massive clamping force only even all over. Start at the center and work out so the liquid doesn't lump in the center.

[Jeff_G]

If you are using epoxy you don't use mat. If the original boat was not epoxy I would go back with poly. Use mat between the layers of ply. To clamp the pieces together simply screw them together with some SS wood screws and torque them as you want. Use a lay up resin not finish resin and you can continue to work the pieces without grinding between lay ups. Just glass the knees to the transom, screw them on just to hold them in place, then glass and alternate mat and roving. Finish up with woving and a finishing resin. When mounting anything to the transom pre drill a little larger, fill hole with resin then re drill through plug and you have a watertight hole and the transom won't rot. This is the simpliest, cheapest way and will last for many, many years. Don't try to mix epoxy and poly. Just another opinion.

[Pete 88 Venus]

Originally posted by Techno
I guess your putting the well back in?
I don't see any function they do other than take up internal space & hold water.

Could I really eliminate the splashwell Techno? That would be pretty cool! Then I could make the knees come all the way up. Do you think the water would want to rush all the way up though and come up by the back seat. It does have this sundeck thing on it.

Once you mentioned that I started me thinking about a molded cowling there instead, this would be the perfect time to put one on too. What do you think?

[TUG]

That pretty boat needs somthing black hanging on the back of it:eek: :D :D

[Pete 88 Venus]

yeah, merc power all the way!!

[Pete 88 Venus]

too bad it's a grey motor the previous owner got paint happy with, but same difference.

[Techno]

When outboards were actually clamped to the transom the well served a purpose. You had to have some way to get the C-clamp onto the transom. But now they bolt on. So what purpose does this pocket serve? I don't know. They have a drain hole in the bottom that usually lets water in at rest. Bubble down into the interior of the boat.
I couldn't see it from your pic. but what does the splash well do on yours? If you stopped would it prevent a wake from washing in? I don't see how since its just a kitchen sink without the faucets.
Look at 90% of OB boats and you see the mentality of them being inboards. There is a vast wasted space like there was an engine in there somewhere.
Then there is the jack or setback that puts most of these engines completely out in the open. There sits the splashwell like a storage bin.

A problem with a cowl is the engine can't be trimmed all the way up, it hits the thing first.