Need advice on cracked fiberglass between transom and bottom of hull

[KesselRunner]

Hi!

I'm restoring an older motorboat that is very similar to a Sea Ray SRV 190 built with a hardtop (very obscure Swedish brand). Apart from a new paint job the transom needs to be rebuilt. After lurking the forums during the winter I've finally started the transom rebuild.

I've removed the motor well, removed the inside skin and dug out the transom. The template for the new transom is done, so are some needed repairs to the transom skin. However, there are some cracks I'm unsure of how to repair in the best possible way.

In the hull section just below where the old core was installed are some cracks that run parallell to the transom. These are a few inches in length, about 1/4" from the transom skin and some overlap another crack. Went at it with the dremel to inspect, seems they run 1/12 - 1/8" deep.

Now to my problem, since these cracks are so close to the transom I wonder how to grind out a bevel when the crack is essentially in the corner so that this can be filled in with new cloth and epoxy. The trouble I see is grinding an inside corner this way and still have a good corner radius for the new cloth. I worry that grinding on each side of the crack will make the corner angle sharper which would be a problem for laying the new cloth, will it not?

Hope i describe things clearly, will update with pictures next time I'm at the boatyard.

Any suggestions would be greatly appreciated.

 

[Lectro88]

Well like its been said before... Pics help the guys giving advise, give better advise.

It would be good if you can figure what caused these cracks. sounds like hairline cracks. was it that the transom was weak or abuse or just failed building practices, or products. I realize some of this is a guess at best.
But if you had a transom flexing from being compromised, and that caused the cracks, and you repair transom and lay over cracks. All should be good is where I'm going with this.
Ask yourself this question, will your repair fix the problem or will they come back. (From a different problem)find the culprit or weak place and fix it, then do your repair.
Now so far as grinding out the cracks... I venture to say you could build or lay over them with more material or for a lack of better words, Beef it up and fix the transom and probably not have any more troubles.
But without seeing what your seeing(no pics)my words are a guess too.
Some others may have different thoughts.
thats my .02 cents.

 

[Scott Danforth]

Most likely you need to do a full restoration of the hull.

Go to the stickies at the top of the forum. 4th one down is the DIY links. Read links 14, 15, 18, 2, 3, 4a, and 4b in their entirety. Read every post, watch every video. Your answers are there

 

[KesselRunner]

Well like its been said before... Pics help the guys giving advise, give better advise.

It would be good if you can figure what caused these cracks. sounds like hairline cracks. was it that the transom was weak or abuse or just failed building practices, or products. I realize some of this is a guess at best.
But if you had a transom flexing from being compromised, and that caused the cracks, and you repair transom and lay over cracks. All should be good is where I'm going with this.
Ask yourself this question, will your repair fix the problem or will they come back. (From a different problem)find the culprit or weak place and fix it, then do your repair.
Now so far as grinding out the cracks... I venture to say you could build or lay over them with more material or for a lack of better words, Beef it up and fix the transom and probably not have any more troubles.
But without seeing what your seeing(no pics)my words are a guess too.
Some others may have different thoughts.
thats my .02 cents.

Yes, the transom was indeed compromised and the cracks are most likely due the resulting flex of the skin as you say.

My thought was that it would probably be enough just to add a layer of biax mat as I'm also replacing the core but now that I have it all open I'd rather completely grind the cracks away and and rebuild these corners. Doing this repair on any other area would be much simpler with the bewel and bigger and bigger layers of biaxial mat but creating bewels for a long hairline crack parallell to the inside of a corner bothers me as the radius of the corner will be really small. Pics coming up!

 

[KesselRunner]

Most likely you need to do a full restoration of the hull.

Go to the stickies at the top of the forum. 4th one down is the DIY links. Read links 14, 15, 18, 2, 3, 4a, and 4b in their entirety. Read every post, watch every video. Your answers are there

Yes these are great and the videos from Frisco (also JMink, Boatworks Today and some others) is the reason I feel confident in doing this and it's what I use as a guide. I have however not seen any inside corners being rebuilt in any of these even though I understand the same logic and method applies as when these types of cracks are repaired in other places but I wanted to make sure I do this the right way since the inside corners add some complexity. I do not want any trapped air under the biaxial mat because I've tried to glass over a too sharp angle.

Current thought is creating two bewels on each side of corner and then start building from the crack (essentially center of inside corner) with really thin strips of fiberglass (for which a sharp angle would not be a problem) until I have built up something like a fillet with biaxial mat in the corner and then start laying the mat over the corner stretching a bit further onto both hull and transom.

 

[KesselRunner]

So, these pictures show how long the cracks are and how close they are to the transom skin.

Current thought is creating two bewels on each side of corner and then start building from the crack (essentially center of inside corner) with really thin strips of fiberglass (for which a sharp angle would not be a problem) until I have built up something like a fillet with biaxial mat in the corner and then start laying the mat over the corner stretching a bit further onto both hull and transom.

 

[Lectro88]

Sorry to say. I really can't make heads or tails out from either pic.
unless what I'm seeing is really enlarged.
Fiberglass is forgiving if you take the steps that it responds to.
If things don't turn out like, you like... sand it down or smooth it out and give it another go.
you can make the radius that works for you and the glass, a compromise.
Back to grinding out those cracks...
If it were me...
I would sand the area, Not Grind the cracks out or away, But prep the surface for a lay over or 3... Until you feel certain that you have blended and built up enough to cure the problem.
My thought on this is grinding away material just to remove cracks or to hold a radius. Is removing strength that you have to replace.(Leave It)
Unless you feel there is contamination like oil or mold.
If it works against you to grind the cracks away. sand it and build it up and be done.
Fiberglassing is what you make it out to be..
Remember. epoxy that is a thin viscosity can seep into these cracks and fix alot of your problems anyway.
Now again surface prep.
Sand, grind, scuff.. Get any oil out. Acetone, with careful use of air hose can lift stuff out you could spend hours on cleaning.(safety glasses)
Another option is Dawn soap and add hot water will flush contaminates out, again air hose used in the right way can speed things up.
(Again, safety glasses)
A Clean, scuffed, Dry surface. And build it up.
If the radius takes more room than expected you can shave or grind any wood to be set to match "Your Work" Blend it..
This stuff doesn't have to hold 0 tolerances. If you add an inch in glass and wood was supposed to go there cut the wood.. an Inch.
This is now "Your Build"... how you want it. Make it yours.
Fiberglass and epoxy is much stronger than many give it credit, or realize.
2 extra layers is better than,. 1 layer too few.
Have fun.

 

[KesselRunner]

Ok, I have highlighted the different things in the picture to make for easier viewing and orientation. As you can see the cracks run parallell to the transom.

 

[KesselRunner]

Sorry to say. I really can't make heads or tails out from either pic.
unless what I'm seeing is really enlarged.
Fiberglass is forgiving if you take the steps that it responds to.
If things don't turn out like, you like... sand it down or smooth it out and give it another go.
you can make the radius that works for you and the glass, a compromise.
Back to grinding out those cracks...
If it were me...
I would sand the area, Not Grind the cracks out or away, But prep the surface for a lay over or 3... Until you feel certain that you have blended and built up enough to cure the problem.
My thought on this is grinding away material just to remove cracks or to hold a radius. Is removing strength that you have to replace.(Leave It)
Unless you feel there is contamination like oil or mold.
If it works against you to grind the cracks away. sand it and build it up and be done.
Fiberglassing is what you make it out to be..
Remember. epoxy that is a thin viscosity can seep into these cracks and fix alot of your problems anyway.
Now again surface prep.
Sand, grind, scuff.. Get any oil out. Acetone, with careful use of air hose can lift stuff out you could spend hours on cleaning.(safety glasses)
Another option is Dawn soap and add hot water will flush contaminates out, again air hose used in the right way can speed things up.
(Again, safety glasses)
A Clean, scuffed, Dry surface. And build it up.
If the radius takes more room than expected you can shave or grind any wood to be set to match "Your Work" Blend it..
This stuff doesn't have to hold 0 tolerances. If you add an inch in glass and wood was supposed to go there cut the wood.. an Inch.
This is now "Your Build"... how you want it. Make it yours.
Fiberglass and epoxy is much stronger than many give it credit, or realize.
2 extra layers is better than,. 1 layer too few.
Have fun.

I'm honestly not sure what could be in the cracks since they run quite deep (1/12 - 1/8") so I'm unsure on the adhesion if I would just let resin sink into the cracks. Smelled something petrol like in the old wood so it seems the old core had sucked up some (oil mixed) gas.

I see some old repairs on the outer transom skin where the adhesion failed that I'm also fixing now. Want to make sure that if I make an effort to fix these cracks that does not happen. Thanks for the tip about the acetone + air hose, really had not thought of that as a solution to get stuff out of the cracks.

 

[Lectro88]

Let me clarify a few things.

! 1st. I'm not an expert nor claim to be(but I have done a considerable amount of epoxy & fiberglass work)

There are "Many" little quirks when it comes to epoxy and poly.
"Typically" poly doesn't like to adhere to epoxy. but with much patience time and attention to detail it can be done most times. but its a pain.(typically)
Now, epoxy will bond to poly, or anything, if you get the surface right...clean & dry and a little scuff.
And that statement stands true for All glass work. keep it clean, sanded and dry. and reasonably warm. epoxy esp. +65F.
Read up on the subject of epoxy and poly and watch some youtube.
I have gained so much information in under 3 yrs that many skilled tradesmen spent 5, 10, 20 years learning.(back in the day before internet)
Its easily available. [and many of them learned by book or hard knocks]
once you get your 1st. success with glass you will be on a roll.
and your confidence will build.

2nd.
I gave the long winded answers (figuring)that you hadn't done much glass work considering the # count of you post's (1)when I replied.
I do what I do now in part from the folks on this forum and 1 other.
The boating people are very helpful and free giving of their knowledge(most times)we are happy to lend advise.

3rd.
1/12"-1/8" cracks is not deep to me. these are common in many boats as time goes on. not desirable, but it happens with age and failures.
Cracks on exterior or cracks seen from both sides is not good.
but small hairline cracks should be easily overcome, as I said in my first reply if you address what was suspected to have caused them to begin with.
Now let me clarify 1 other thing.
When I said epoxy will seep into existing cracks.
I DIDN'T mean that alone was a fix...
I was pointing out that when cleaned thoroughly (theres that again)
During the repair of adding glass.. The epoxy can penetrate some of the cracks. And leaving that rather than trying to remove all cracks and start all over would be "my" pick. Because if 1 started sanding out every little crack. Some boats wouldn't have anything left or would look like swiss cheese or the target of a skeet shoot. to be funny.
So, surface prep. combined with a layer or few of glass should handle your concerns.
If I have said something out of line I'm sure someone will chime in.
But there are many ways to do repairs. and I'm sure you will find your way.
You could also try your hand at a different, simpler repair in another location of boat before you tackle this one,
If this is your only problem you probably have it pretty good.

Let me say 1 last thing that is not my words but its said over and over on here.
Most times the repairs we do ourselves is superior to original boat builds from boat builders.
As we tend to take our time and get it right or Over Do things, just because we are there, and a lot of times we don't realize how much we are overdoing things. but thats ok. Like I said earlier, I'll take 2 extra layers over 1 too few... every Time.
its how most of us do. and most times we give it time to do its healing (cure and dry) I'll call it.
Boat builders make money by getting boats out the door in production.
And that combined with abuse, neglect, time and years is why we all are doing what we're talking about on here.
We on the other hand will probably never recoup our efforts, time or money that we throw at our vessels. call it a labor of love may not be the word but it will work for now.
So that is more food for thought for you to digest and ponder while you learn your way. and plan your repair.
best regards.

 

[KesselRunner]

Let me clarify a few things.

! 1st. I'm not an expert nor claim to be(but I have done a considerable amount of epoxy & fiberglass work)

There are "Many" little quirks when it comes to epoxy and poly.
"Typically" poly doesn't like to adhere to epoxy. but with much patience time and attention to detail it can be done most times. but its a pain.(typically)
Now, epoxy will bond to poly, or anything, if you get the surface right...clean & dry and a little scuff.
And that statement stands true for All glass work. keep it clean, sanded and dry. and reasonably warm. epoxy esp. +65F.
Read up on the subject of epoxy and poly and watch some youtube.
I have gained so much information in under 3 yrs that many skilled tradesmen spent 5, 10, 20 years learning.(back in the day before internet)
Its easily available. [and many of them learned by book or hard knocks]
once you get your 1st. success with glass you will be on a roll.
and your confidence will build.

2nd.
I gave the long winded answers (figuring)that you hadn't done much glass work considering the # count of you post's (1)when I replied.
I do what I do now in part from the folks on this forum and 1 other.
The boating people are very helpful and free giving of their knowledge(most times)we are happy to lend advise.

3rd.
1/12"-1/8" cracks is not deep to me. these are common in many boats as time goes on. not desirable, but it happens with age and failures.
Cracks on exterior or cracks seen from both sides is not good.
but small hairline cracks should be easily overcome, as I said in my first reply if you address what was suspected to have caused them to begin with.
Now let me clarify 1 other thing.
When I said epoxy will seep into existing cracks.
I DIDN'T mean that alone was a fix...
I was pointing out that when cleaned thoroughly (theres that again)
During the repair of adding glass.. The epoxy can penetrate some of the cracks. And leaving that rather than trying to remove all cracks and start all over would be "my" pick. Because if 1 started sanding out every little crack. Some boats wouldn't have anything left or would look like swiss cheese or the target of a skeet shoot. to be funny.
So, surface prep. combined with a layer or few of glass should handle your concerns.
If I have said something out of line I'm sure someone will chime in.
But there are many ways to do repairs. and I'm sure you will find your way.
You could also try your hand at a different, simpler repair in another location of boat before you tackle this one,
If this is your only problem you probably have it pretty good.

Let me say 1 last thing that is not my words but its said over and over on here.
Most times the repairs we do ourselves is superior to original boat builds from boat builders.
As we tend to take our time and get it right or Over Do things, just because we are there, and a lot of times we don't realize how much we are overdoing things. but thats ok. Like I said earlier, I'll take 2 extra layers over 1 too few... every Time.
its how most of us do. and most times we give it time to do its healing (cure and dry) I'll call it.
Boat builders make money by getting boats out the door in production.
And that combined with abuse, neglect, time and years is why we all are doing what we're talking about on here.
We on the other hand will probably never recoup our efforts, time or money that we throw at our vessels. call it a labor of love may not be the word but it will work for now.
So that is more food for thought for you to digest and ponder while you learn your way. and plan your repair.
best regards.

Thank you very much for the lengthy reply, I really appreciate hearing other peoples thoughts on how to handle these types of repairs, how they reason and what their background in fiberglassing is.

Having the internet is truly a blessing, even though I do not much more experience than some simpler repairs I feel I have plenty of the theoretic background which is a great guiding hand!

Thanks again!

 

[chevymaher]

Black is bad. Peel skin off to find what Scott is warning of. Then start demolition once in your heart you know the black that looks like rot is rot.

 

[KesselRunner]

Black is bad. Peel skin off to find what Scott is warning of. Then start demolition once in your heart you know the black that looks like rot is rot.

Could you please elaborate? Are you talking about the black stains on the fiberglass? The plywood core is already dug out from the transom.

 

[chevymaher]

okay yea that was it. It just needs redone now. Take it all out and redo it.