B25 transom/bracket mounting

[Corey Mason]

Got the old outdrives off recently.

We already have an Armstrong bracket. It's not a custom made one, but one we picked up off the internet. It's a twin set up, floatation bracket.

The flotation part under the "swim deck" area is able to JUST fit inside the bump out portion. We were thinking of installing it straight on to the bumpout and essentially fiberglassing in "shims" on the out sides where the transom would curve away from the bracket.


Thoughts?

We need to glass in our holes still. We actually probably need to cut alot of the bumpout away and reglass it. Decent bit of rot in there. Not sure how much til we start cutting, but I'm assuming it's pretty far.


How have you guys done it? Pictures?

We both have never touched fiberglass. Any tips appreciated. Father in law thinks somebody else should be hired for it. I say, we better learn to do it ourselves or this project will exponentially get expensive!

[Yannis]

Corey,

This is a fairly technical job on a very crucial part of the boat. I would assume it takes some skill to do it right. It has to be right all the way.
To put it differently, a heart surgery is damn expensive but I wouldn’t try doing it myself to save some coin...

[CamB25]

Corey,

Re-coring the bump out is not too difficult. Hardest part, and most of the labor cost, is getting all the old wood out! I removed the old core and made a new core (2 pieces of 3/4 (23mm) fir plywood) myself, but since I had the boat at a shop I had them install and glass the holes for convenience. They vacuum-bagged the core with 8 layers of glass, then epoxied into place. See pictures:
https://www.amazon.com/photos/shared/bu ... U7N7LU7Da2

It's not rocket science, but if this your only major fiberglass work on the boat, it might be better to hire out the installation instead of investing in tools and education/practice.

I have seen pictures of brackets with the filler pieces between the hull and the bracket. Do-able.

Good Luck!
Cam

[John Swick]

Go at it from the inside.
You might be surprised how well the old transom core held up(?).
Do the grunt work (old core removal) yourselves to save some of the labor costs and have the pro's glass in the new core.
It's not rocket science, but it is structural, so maybe not the area to learn on.
I'd use coosaboard or gatorboard for the core material.
Good luck.

[Corey Mason]

Hmm, I may end up getting some estimates then. How much would you guys expect to have the trans one repaired and bracket installed? I'm guessing $2,500?

Would it be easier to just cut most of the bumpout out entirely and just use one/two thick pieces of filler instead of even bothering to figure where to core is good or not good?

[ktm_2000]

I recently took out the core of my transom and put a new core in, cold weather has put my project at a standstill so it is not quite finished. I've done quite a bit of glassing and working with epoxy so I didn't think much about doing this project, but if I were not experienced I would not have taken it on, if you think about it, you are going to bolt on @600# and 250-300hp so the forces involved are quite significant. Add on to that the cost of the motor being @$20,000 or more and what happens if you mess it up?

as for getting the old core out, OMG was it a pain. easily 16+ hrs labor to get the core out. There were 50+ SS ring nails holding the layers of plywood together and the Bertram folks did a fabulous job laminating everything together so nothing came out easy. Destroyed a couple cheap circular saw blades cutting relief cuts, Lots of time with chisels and pry bars. Towards the bottom under the outdrive holes my core was wet but in no way breaking down. Had to cut out @6" of the center stringer to get the last bit of the transom down low.

core out
https://photos.app.goo.gl/MydXWfZyDpXZJ4Ho9

new core going in
https://photos.app.goo.gl/tGg8sB4RzkzWniAx6
https://photos.app.goo.gl/9b95j5CJgspevTmNA
https://photos.app.goo.gl/WycDKaWaV1Qg8HN38

[Corey Mason]

No center stringer for me, so not too bad.

Hmm ok. I was thinking you just cut the entire thing out with a sawzaw. This makes more sense now.

I bet an air hammer/chisel would make things a little easier.

Think I may get it down to where you have it, then have it glassed by a pro.

[CamB25]

Nice work and pictures, Matthew! I too remember the quality time spent with chisels, hammers, grinders getting mine out! Fun times! It's always easier to destroy than create!

Corey - don't go halfway with it. Make it look like mine or Matthews. It is possible to replace the entire curvy transom, but that's a HUGE project. This guy did it:

https://www.thehulltruth.com/boating-ho ... -25-a.html

[Corey Mason]

Yes I saw that guy cam. But much for me.

So, what am I looking at in the picture? I see where you clearly removed the core. What is left? What is the part I'm see that is actually left?

I'm assuming that there is the core on the inside, made of wood. And it is covered by fiberglass on both sides.

So I'm going to cut through the fiberglass on the inside of boat to get to the core. And then dig through the core until I get to the other side of the fiberglass "sandwich" right?

Basically cut wood out til I get to fiberglass and that's what I'm looking at in those pictures?

[CamB25]

You got it!

[Joseph Fikentscher]

If you cut the transom out you could add 3 more feet of boat!!

Just dreaming at the desk today.

[CamB25]

You're right! I was really skeptical when he first proposed the idea, but he pulled it off. You could make an entire bespoke euro-transom plug, or modify one from a wrecked boat. Possibilities are endless!

[cariedl]

Corey -

You're father-in-law and the rest of these guys on here are right. It sounds like the margin of error with the bracket is extremely small and having never done any glasswork you will make errors that could prove extremely costly. Catastrophic failure of the mount, core or anything on the transom would be horrible, especially given all the other work, time and money you're putting in to re-do the boat. Practice working with fiberglass somewhere else on the boat. Taking on something this complex seems with no experience seems dangerous to me. I would advise spending the money on a professional once the cutting and removal is done. Find a shop that knows what they are doing and will let you learn.

CR

[Corey Mason]

That's what we're going to do.

We talked about it. We're going to core it ourselves and then take the bracket and boat to a pro and have him do it.