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Author Topic:   Transom Separating from Boat - 69 Nauset
Soho posted 06-03-2002 08:47 AM ET (US)   Profile for Soho   Send Email to Soho  
Well, After about a two year effort to totally refurbish my 69 Nauset, I have a problem; the transom is starting to separate from the boat.

It started as a hairline 3" crack in the port corner inside. Developed as the boat was trailered back from having the engine put on. I seemed to remember making some repairs on the corner some years ago for a hairline crack so I initially attributed it to the West not picking up the polyester resin that well, and just failing over time. Then picked up a 4" crack on the horizontal "shelf" surface, same corner of the transom, but in from the side of the boat, not joining the other crack. Again I seemed to recall it corresponding to a repair I had made, so I just thought that I would monitor it all. Anyhow, I took a big wave and some air yesterday and the crack on the corner opened up a fair bit more, extended itself over the gunwale and just past the bottom of the rubrail. Maybe an eighth of an inch wide now another crack opened up on the floor near the splash well and a small one appeared on the starboard corner. No cracks have appeared on the outside, except as noted. The boat has a 90 Yamaha on it, so I am not overloaded on weight.

There could be a number of reasons why this is happening - old damage I am unaware of, my previous cosmetic repairs with WEST failing etc.

As long as I do not do alot of really heavy driving, I think that I am okay, well not in danger of the entire transom falling off at least.

My thought for repair was to have an angle bracket made up of stainless and have it run across the back of the top of the tramsom ( external ) around the corner and under the rubrail forward; all on the vertical surfaces. I would route a depression in the glass to bury the bracket. I would bolt it into the hull I would then re-glass over it and put the rubrail back etc.

Any other ideas / comments ?

Thanks in advance, sorry for the length of this.


Ron the depressed !

DIVE 1 posted 06-03-2002 10:03 PM ET (US)     Profile for DIVE 1    
Cosmetic repairs with West Systems. Did you use matting with the epoxy during your previous repairs? Did you scrape or dig down to the root of the cracks to see how deep they were prior to making the repairs? I need more input to provide you with some workable answers.
Soho posted 06-04-2002 07:30 AM ET (US)     Profile for Soho  Send Email to Soho     

Thanks for the response. I did not, to the best of my recollection, use any matting for the prior repairs, I usually do grind back the existing glass a bit to give me a good surface to work on. Unfortunately, anything that was done was done a few years ago, prior to this forum and when I knew much less then I know I know now...

I went down to the boat yesterday to check the damage out again. Some of the cracks on the floor are clearly where an old west repair has been made. Some glass would have helped I think. The floor repair also was exposed to the sun a bit which might have caused it to deteriate a bit and become brittle. The corner of the transom, I do not remember any major repair there, just filling the small crack. In hindsight, I probably should have paid more attention to it. I now have some pictures of the damage now and can post them to you if you want.



Soho posted 06-05-2002 10:27 AM ET (US)     Profile for Soho  Send Email to Soho     
Maybe not much anybody can say to help here, but I would be interested if anybody has experienced this type of strcutural failure before. For instance, what is the composition of the transom/hull joint etc.

I sent a picture off to Boston Whaler technical advice to see what they say. Not heard back yet.

Thanks in advance,


DIVE 1 posted 06-05-2002 10:44 PM ET (US)     Profile for DIVE 1    
Sorry it took me so long to get back to you-work. The boat is repairable with matting and resin. Here is how I would proceed.
1. Remove engine, fuel tanks, batteries, and everything else from the boat.
2. Ensure boat is sitting on trailer correctly to allow the hull to relax and the cracks to hopefully close up.
3. Grind the cracks open and go deep enough to get to the foam (keep in mind that the fiberglass is very thin). If the foam is dry-proceed with repair.
4. Find the end of the cracks and drill a 1/4" hole through the fiberglass at the end of the cracks(this prevents them from reappearing later).
5. From the crack, backgrind a bevel in the fiberglass at least 6" on both sides. Try to get all tracs of epoxy ground off of the original fiberglass.
6.Apply 1 layer of biaxial matting with vinylester or polyester resin to cover the entire area. Cut the next layer smaller to fill in the low center section. Switch to chop mat and cut little pieces to fill in the remaining low spots. The top layer should be 6oz. cloth to entirely cover all previous layers. Use styrene wax on last layer only. Keep fiberglass clean between layers and you will not have to sand between layers. I would get all materials ready and do the entire fiberglass layup at one time so it all cures together. DO NOT USE EPOXY FOR THIS REPAIR.
7. Allow to cure and rough grind into shape(don't go too deep-inside corners require care and finess).
8. Fill all low spots and pinholes with 3M Marine Premium Filler. Allow to dry and hand sand to get desired shape and finish. Reapply Premium Filler as needed and keep sanding.
9. Apply finish - gelcoat, paint, etc.
Have fun and remember, it only itches for a few days.
Soho posted 06-05-2002 11:49 PM ET (US)     Profile for Soho  Send Email to Soho     

Thanks for the detailed instructions. I understand exactly what you describe. Can you explain why epoxy should not be used on this ? My understanding was that epoxy would bond to a polyester resin while polyester on top of ( old ) polyester would not? An old wives tale ? You were emphatic about not using epopxy in your response and I am a die hard West addict.... I am most comfortable using it I guess. Also, what is styrene wax on the last layer.

Thanks in advance,


browning20ga posted 06-07-2002 12:18 AM ET (US)     Profile for browning20ga  Send Email to browning20ga     
DIVE1, Just a question, I thought I read somewhere on this forum that polyester resin would melt the foam if it came into contact with it and epoxy should be used next to foam. Do I have my wires crossed? I think I heard this on the radio interview with the guy from West Systems here on C.W.
Tom W Clark posted 06-07-2002 12:48 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

Polyester (or vinylester) resin WILL NOT melt polyurethane foam. It will melt Styrofoam. Whaler are filled with polyurethane foam, not Styrofoam. This is why the polyester resin skins of a Whaler do not melt the polyurethane foam filling when it is built.

Epoxy will melt neither Polyurethane foam nor Styrofoam.

DIVE 1 posted 06-07-2002 08:28 PM ET (US)     Profile for DIVE 1    
Epoxy has its place-repairing dings and scratches. It is easy to use, versatile and sands easily. I like to use it for the above applications. The problem is that epoxy does not bind with matting very well. I have seen numerous repairs fail because of this problem.
All fiberglass repairs are considered a secondary bond and are never as strong as the original layup. To duplicate the original layup, use chopped mat and polyester resin. To get the maximum strength, use biaxial matting and vinylester resin.
Styrene wax is a liquid that is added to the resin. As the resin cures, the wax rises to the surface and provides an airtight layer so the resin dries(no tacky surface). It should only be used on the final layer. If you use it on any layer prior to the final layer, it must be sanded between layers.
An alternative to adding styrene wax is to use premade resin without wax for the first few layers and then use a finish resin with wax added for the final layer. No sanding between layers.
Ed Z posted 06-08-2002 09:09 PM ET (US)     Profile for Ed Z  Send Email to Ed Z     
I just checked out my 69 Nauset and also found a couple hairline cracks near the pedistals on each rear corner... I hope this doesn't lead to further separation as did yours... I do tend to run it rather hard in ruff water (just jump from peak to peak of the waves)... If this grows into a major repair job, I may just say enough is enough and get me a new 170...
Soho posted 06-09-2002 10:33 PM ET (US)     Profile for Soho  Send Email to Soho     

Thanks for the explanation. Boston Whaler gave me the same advice really in terms of repairing with polyester resin. No problem I think that I can handle this. Just damn disappointing as I had the boat out for four years and worked on her the last 18 months. to repair the transom would have not been an issue had I known thus would happen. Now I have had the boat awlgriped and am back in the water during the boating season and I have to pull her again. Fortunately, I think that I can get this done fairly quickly and have her back in.

Ed Z - you know I used the boat from 92 when I bought her to about 98 when she came out and the transom was fine - and I took some licks during that time- I think that I had a small hairline which I fixed - seems like maybe it was deeper..



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