Just a transom rebuild...

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yardbird
Posts: 120
Joined: Thu Jul 20, 2017 3:50 pm

Just a transom rebuild...

#1 Post by yardbird » Fri Oct 13, 2017 5:33 am

1990 Landau.
Had a 30hp 2-stroke, replacing with a 40hp 4-stroke. The transom was getting really.... soft... so I decided to replace it. It’s wood. I looked at just getting it redone in aluminum, but honestly, the materials cost is high and finding someone to fabricate.... not just weld... was proving difficult. So.... it was wood... and will be wood again...

I bought a piece of 3/4 marine ply. The plan is to laminate 2 layers with epoxy glue, cover the entire thing with several coats of epoxy, and put it back on the boat.

Well.... it’s not 1-1/2 inches thick as I had thought. It’s 2 inches. So I need another 1/2 inch. I think I’m going to just get a good piece of 1/2 inch exterior ply and sandwhich it in the middle. Everything will be coated with epoxy so.... hopefully it’ll be fine.

First thing I did was build a jig. Simple. Not only is the transom a trapezoid, but the sides are angled slightly to conform to the transom pod. That will help as I dry fit the pieces before epoxy.

I’m going to be taking pictures at various stages of this, but here is what I’m starting with.
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yardbird
Posts: 120
Joined: Thu Jul 20, 2017 3:50 pm

Re: Just a transom rebuild...

#2 Post by yardbird » Fri Oct 13, 2017 7:38 am

First things first... make a template. Similar to making a template for a counter top.
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yardbird
Posts: 120
Joined: Thu Jul 20, 2017 3:50 pm

Re: Just a transom rebuild...

#3 Post by yardbird » Fri Oct 13, 2017 7:54 am

One thing I noticed when taking this apart was that the holes must have been drilled by a drunk guy. They go at weird angles and no 2 are the same. Once I get the pieces cut and dry fitted, I am going to have to redrill. Might have extra holes then, but I really can't go through all this and leave them the way they are. Because of that angle the holes on one side will be 1/8 inch off the center line towards the outside, and the holes on the other side will be 1/8 inch off the center line toward the inside.

So... besides the additional piece of 1/2" plywood, I have to make sure I have a drill bit the correct size for the through-bolts and long enough to go through 2-1/4 inches of aluminum and wood! If my drill press doesn't have a long enough travel... I might be doing that by hand. Always exciting.....

yardbird
Posts: 120
Joined: Thu Jul 20, 2017 3:50 pm

Re: Just a transom rebuild...

#4 Post by yardbird » Fri Oct 13, 2017 1:42 pm

Pieces cut and dry fit.
Next step is to glue the 3 layers together. Unfortunately I have stuff to do this weekend so I may not get back to this until Monday or Tuesday.
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TDJ2591
Posts: 325
Joined: Mon Jun 02, 2014 4:33 pm
Location: Smith Lake, AL

Re: Just a transom rebuild...

#5 Post by TDJ2591 » Mon Oct 16, 2017 6:41 am

Many years ago I rebuilt the decking and transom in my bassboat in a similar manner but encased all wood in fiberglass cloth and resin. It's less likely to crack than an epoxy coating and adds some strength. The weak spots are any hole you drill into the finished pieces and the cut edges of the plywood. If water can seep it, it will eventually deteriorate. I drilled holes large enough to insert brass tubing with i.d. the size of the bolts and sealed and epoxied the tubing in place.

I would love to have rebuilt the transom from solid fiberglass but didn't have the set up or experience to create it.
[color=#4000FF]2005 Crest Caribbean 25'
2006 Honda 135hp 4 stroke[/color]

yardbird
Posts: 120
Joined: Thu Jul 20, 2017 3:50 pm

Re: Just a transom rebuild...

#6 Post by yardbird » Wed Oct 18, 2017 6:20 am

Yeah, I thought about a lot of ways to try and do this, but at some point I gotta stop thinking about it and actually get to doing it.

As far as strength.... it's 2 inches thick! and I'm only hanging a 40hp on it. The old one was in there for an awfully long time and it wasn't even epoxied. It was just bare. Not painted... nothing. Now, in fairness, I think this boat's probably been trailered and launched its whole life and not dropped in a slip for months at a time, so I guess we shall see what we shall see. If it needs a new transom again while I own it, it's going to be all aluminum, but right now... this is what I got.

I thought about glassing it, but.... I really don't think it needs it in terms of strength. It might help as far as whether or not I get checking in the plywood which I know can happen with epoxy alone so I'll keep an eye on it.

I'm paying special attention to the edges and they're getting about 5 coats of epoxy. The faces will get 3 coats... maybe more if I'm careful with the epoxy. I wasted about 100 ml so far as I mixed too much and it went off before I could apply it all. I bought a bunch of clear measuring cups from the dollar store so I can pour in like... 50ml of hardener and then pour in 50ml of resin and be really accurate (I checked the cups with known measures to make sure the markings were accurate)

The transom wood is trapped in the channel of those side pieces so they'd REALLY have to come apart bad in order to dump the motor in the drink. I mean like I'd need a catastrophic failure of about 2 inches of wood down an entire side. And I doubt it could get that far without me noticing a problem. The old transom wood was deteriorated along the edges pretty bad and soft in the middle and it still held the motor on there.

I'm still debating how to treat the holes that I have to redrill through the side channels and wood. I might do the through-drill, then pull the wood and redrill them a little oversized, fill with epoxy, and then drill again at correct size for bolts. I have a little time yet. I am MOST concerned with any holes that will be under water while the boat is in the slip. Which is basically just that bottom pair of holes. The others are not under water. I was told by a local guy to just fill those with silicone caulk before pushing the bolts through and then clean up the mess. I'd still like to get epoxy in the holes though because I can SEE how it penetrates into the wood.

I still can see I have a few more days of this.... apply epoxy, wait for it to dry, flip, apply more epoxy, then wait 24 hours before doing it again... although I'm rethinking even that a little. I can recoat after 6 hours at 70 degrees, but have to wait 24 hours to do any sanding. I have about 5 or 6 days of around 70 degree outdoor temps so I can do this with minimal heating in the shop and spot heating on the piece.

And sorry for being so wordy, but I've seen several topics about rebuilding transoms and still had a hard time envisioning what all was involved. It sounds simple but it's pretty time consuming. Not that you have to be actually working on it all that time, but a lot of waiting for stuff to dry.

yardbird
Posts: 120
Joined: Thu Jul 20, 2017 3:50 pm

Re: Just a transom rebuild...

#7 Post by yardbird » Wed Nov 01, 2017 9:34 am

Almost forgot to wrap this up.
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yardbird
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Re: Just a transom rebuild...

#8 Post by yardbird » Wed Nov 01, 2017 9:36 am

4 coats of epoxy. Edges got 6. This is actually dry. Oh and I used a very tiny bottle brush to get epoxy into the holes.
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yardbird
Posts: 120
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Re: Just a transom rebuild...

#9 Post by yardbird » Wed Nov 01, 2017 9:38 am

Back on the boat. May be all the progress we get for now. Unless we get some very nice weather unexpectedly. Otherwise, she's covered until spring.
Even though I managed to epoxy those holes, I still loaded them with a good silicone sealant as I was installing the bolts. So.... it is what it is at this point.

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curtiscapk
Posts: 4873
Joined: Mon Nov 10, 2008 8:31 am
Location: OP KS\Truman Lake

Re: Just a transom rebuild...

#10 Post by curtiscapk » Wed Nov 01, 2017 9:45 am

LOOKS GREAT!
Craig and Paula
"THE FLOATER" rebuild Spring 2013
viewtopic.php?f=2&t=15328
94 Party Barge 24' 115 merc
Turning Point hustler 14 x 13 prop
22mph gps 3 people
12 F150
Overland Park Ks
Boat at Truman Lake, MO

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Rick McC.
Posts: 148
Joined: Fri Mar 31, 2017 7:12 pm
Location: Weeki Wachee, Fl

Re: Just a transom rebuild...

#11 Post by Rick McC. » Wed Nov 01, 2017 10:36 am

Excellent, Sir!
Rick

Sights are for the unenlightened.

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curtiscapk
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Location: OP KS\Truman Lake

Re: Just a transom rebuild...

#12 Post by curtiscapk » Wed Nov 01, 2017 11:51 am

I replaced one overnight!!!! :eviltaunt

Brand new transom cracked on the outside board what the hell, 3 hours and bad! Admiral was ready to pack it in forever! Well I couldn't have done it without my guests and my bro and his bro inlaw, but we replaced that transom in 5 hours! Thank god for my scrap PS plywood! Trying to heft a 500+ pound motor on the fly was interesting but we did it. I made a safety chain too that helps support the weight..
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Craig and Paula
"THE FLOATER" rebuild Spring 2013
viewtopic.php?f=2&t=15328
94 Party Barge 24' 115 merc
Turning Point hustler 14 x 13 prop
22mph gps 3 people
12 F150
Overland Park Ks
Boat at Truman Lake, MO

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