Restoring a 1963 Sea King! NEED HELP! Transom Repair...

acminor

Cadet
Joined
Apr 29, 2015
Messages
9
Hello anyone,

I am currently in the middle of a huge project and have almost no idea what to do going forward.

Background info: The boat is completely sanded and the transom outer skin has been cut out with a 2 inch gap from the hull. Almost all of the wood was rotted and so it was removed. I removed the floor the previous owner had placed inside only to find extensive damage to the stringers.

I need to know how much resin I will need? How much and what kind of fiberglass mat/roving will I need?

I can post pictures if needed.

Thanks in advance,
Chase
 

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
Yeah, pics will be helpful. Hopefully you don't mean you cut out the entire back side of the boat!!!!:eek::faint2:
 

sphelps

Supreme Mariner
Joined
Nov 16, 2011
Messages
11,429
Yep ! We love pics ! Welcome aboard !
I know it,s a bit late but we almost always recommend cutting the inside skin out to replace a transom and not the outside ...
It can be done from the outside but structurally and cosmetically it's better from the inside ...;)
 

acminor

Cadet
Joined
Apr 29, 2015
Messages
9
Ok well I can't get the pictures until tomorrow. I already cut it from the outside becuase to get to the inside piece the entire hull would need to be seperated. It'll make more sense when I get the pictures up...
 

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
24,829
We know, the 2 halves separate is more work prep, but might be less work in the end, but give a better result, IMO.

You'll still have challenges to overcome, but it can be done from the exterior.

Pix when you can
 

acminor

Cadet
Joined
Apr 29, 2015
Messages
9
Here's just a couple pics.
 

Attachments

  • download_20150503_175829.jpeg
    download_20150503_175829.jpeg
    252.4 KB · Views: 1
  • download_20150503_212134.jpeg
    download_20150503_212134.jpeg
    284 KB · Views: 1

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
I would have recommended this method...



Would have been a LOT easier to do and much easier to repair on the "Go Back". But, what's done is Done!!!

Soooo... What's your plan now?
 

acminor

Cadet
Joined
Apr 29, 2015
Messages
9
As of right now my plan is to cut a piece of exterior grade plywood. One 1/2 inch and one 3/4 inch so it will be the original thickness. I will epoxy the two pieces of plywood together and then epoxy the inside layer of the transom as well. Let both cure and then epoxy the outside piece back on and fiberglass the gap from the previous cut. I will have to do a little bit of gel coat repair around the cut.
 

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
Uhmm, the Transom is THE most structural component of the boat. How big of Motor will you be hanging off of her? With the Motor hanging on it, it sustains a lot of stresses to it. I'm afraid your plan is not sufficient to accommodate all of the forces and stress that it will be put under. I would encourage you to do a lot of research here on the forum to learn more about transom replacements and what needs to be done especially doing it the way you are. Using Epoxy IS a good idea since it's a very strong adhesive. You'll need that. You'll also need a lot of other issues to be covered. How thick is the inner skin? How well is it tabbed to the sides and bottom of the hull.? Having left a bit of a lip on the upper part of the outer hull, I'm not quite sure how you're going to get the new wood core into place?:confused: Also, Make sure your measurements are exactly Spot On. Most transoms are 1.5" thick not 1.25". In a Normal transom replacement the entire inner skin is removed, the wood core is glued to the outer skin and then New Glass and resin is applied to reform the inner skin and attach everything back to the hull on the inside and this is where the majority of the strength is gained. Doing it your way will necessitate doing the tabbing on the outside. So as you can see, just regluing the old glass piece back on and patching the seam is not really going to be sufficient.

Now, I AM just an Old Dumb Okie, and this IS just my opinion soooo, you should always do your own research and listen to all the experienced advice you can and then "Go with your Gut!!!":D;)
 
Last edited:

sphelps

Supreme Mariner
Joined
Nov 16, 2011
Messages
11,429
Epoxy will be your strongest repair but if you plan on gell coat over it from what I here does not bond as well . Something about getting rid of the blush that epoxy produces .
 

acminor

Cadet
Joined
Apr 29, 2015
Messages
9
Outer skin and inner skin thickness is about 1/4 in. I am now thinking about not attaching the old outside skin and instead place a new layer of glass mat, glass roving, followed by two or the more layers of glass mat. I will be putting a 1950's era mercury Mark 58a 50 hp motor.
 

acminor

Cadet
Joined
Apr 29, 2015
Messages
9
Now all I need to know is what epoxy system to use. AND how much I will need. Looking to keep price down if at all possible.
 

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
I'd recommend U S Composites They have good prices and products. Get the 3 to 1 epoxy and get the pumps. Makes it soooo much easier to measure. If all you're doing is the transom I'd recommend the 2 gallon kit. You don't use Glass Mat with epoxy, only fabric. I'd recommend 8.5oz eglass and use multiple layers. Lot's more strength that way. Keep posting pics and asking questions. We'll be here to help thru the entire process.
 
Last edited:

zool

Captain
Joined
Aug 19, 2012
Messages
3,432
The proper way to do an outside transom repair is to adhere the new wood to the inner skin, like you plan. You can also reattach the cut out portion of the outer skin, if you grind and clean the inner side of the outer skin thoroughly, and clamp them tight together, epoxy would be best, like you plan.

What you havnt planned on, and you need to, is you need to grind about 12 inches in both directions from the seam, and feather it...that means around the side corners at a minimum, and preferably the bottom. You then wrap the lams around the back sides, and up the sides of the hull, built back up the original hull side thickness. Then fair it all smooth and finish. You can glue the wood and skins in with epoxy, and do the lams with epoxy also, as long as you clean any amines off thoroughly, before gel coating, or you can do the outer lams in poly, to better accept the gel.

All the fairing required is why it usually better to do the repair from the inside, where fairing isn't necessary..

If you just repair the seams cosmetically, it wont be structurally strong enough, and your motor can pull the transom out.
 

henleyhale

Petty Officer 2nd Class
Joined
Oct 5, 2013
Messages
136
I see alot of talk about epoxy resin systems here, but strength rigidity and adhesion would best be suited to use vinyl ester resin in my opinion, this will also take gel coat well, i would use epoxy to bond to the inner skin and likely use poly puttied with talc to bed the new wood into the bottom and sides, either system epoxy or vinyl ester will do well, but zool is 100% correct when he says you need to wrap that repair 6" around the sides and bottom of the boat.

P.s. vinyl ester resin needs a well ventilated area, outside with a fan blowing it down wind from you pointed at your least favorite neighbor. Work from one side to the other with the fan at your back, the fumes will give you quite a hellaciois headache for about 2 days
 
Last edited:

acminor

Cadet
Joined
Apr 29, 2015
Messages
9
Thank you all for all the advice! I watched a youtube video of the guy who runs www.boatworkstoday.com and he was showing that the gel coat will stick to epoxy extremely well. Since I have ditched the idea of reattaching the old outer skin to the plywood core, I want to make sure my gel coat will adhere to the new transom. Since I live in a somewhat nice neighborhood I doubt they are going to appreciate the extreme fumes of vinyl ester resin. Boatworkstoday also said never to place poly on top of epoxy because it won't always bond correctly.

Thanks again!
 

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
24,829
the boatworks today videos are a good resource and I highly recommend them

there has been some debate on this forum and another about his epoxy and gelcoat tests, he hasn't posted any long term results yet, he did work all in 1 product line from WestSystems, which is an important detail, and working w/ 1 resin 'family' of products designed to work together isn't always the case

Search for posts by Ondrvr, he's our resident resin expert, and still doesn't recommend putting gel over epoxy
 

zool

Captain
Joined
Aug 19, 2012
Messages
3,432
Thank you all for all the advice! I watched a youtube video of the guy who runs www.boatworkstoday.com and he was showing that the gel coat will stick to epoxy extremely well. Since I have ditched the idea of reattaching the old outer skin to the plywood core, I want to make sure my gel coat will adhere to the new transom. Since I live in a somewhat nice neighborhood I doubt they are going to appreciate the extreme fumes of vinyl ester resin. Boatworkstoday also said never to place poly on top of epoxy because it won't always bond correctly.

Thanks again!

You wouldn't be putting poly over epoxy if you glue it in with the epoxy, and laminate a new outer skin in poly, you would just be reconstructing a polyester outer shell, with more poly....the two resins would barely meet, if at all. BTW, if you're applying gel over epoxy, then you are basically putting poly over epoxy, just not structurally, so boatworks is kinda contradicting themselves...

Bottom line:

Gel over poly resin is polyester over polyester, so no issues.

Gel over epoxy wont chemically bond, but a properly cleaned and sanded epoxy base will hold gel, provided all the unreacted amines (blush) is removed. That just involves multiple washes with water, then a solvent wipe.
 

acminor

Cadet
Joined
Apr 29, 2015
Messages
9
Ok so with all that said about how much polyester resin will I need for the transom.The boat has a 5' 10" beam. And fiberglass mat, cloth, or roving?
 
Top