Hi everybody,
I am new here, but many probably know me from other cat and multihull forums. The reason I'm posting here is that I need advice to fix a Supercat 15 bow that failed near the crossbeam. Following advice received elsewhere, I wrote directly to Aquarius-Sail emails, but input from the forum participants is also welcome, so here is the whole story:
A few months ago I made a deal with the owner of a Boston Whaler Supercat 15 to restore his boat in exchange for its use. The boat was abandoned under the sun uncovered for about five years, so the first thing I did was a basic structural test: raised one bow to see if the other remained paralel. It seemed to be rigid, like other SCs I checked for comparison. Then I sailed and raced it with borrowed parts for about two months. Everything was normal, mostly it needed replacment of sun damaged parts (tramp and a few lines) and lost hardware (a jib block, tiller extension, battens, traveller ends, drain plugs,etc.).
While we waited for the new parts, the boat went to a shipyard to be painted. In the end, it was completely re-coated with gelcoat, longboarded and polished. It looked like new and was at least as fast as the other SC15s racing one design here.
One or two months ago it was re-launched and since then we sailed or raced it each weekend. A week ago it pitchpoled with about 30 knots wind, fighting for the lead. The mast base broke its "neck" and, more important, the inside of the bow side near the mainbeam cracked open. The two damages are certainly related and I tend to think that the bow failure caused the mast base rupture.
Anyway, the bow damage extended further when the boat was slowly towed to shore upside down and backwards, with the severed bow slightly up to keep it from flooding or breaking too fast. In the end the bow was nearly separated from the rest of the float at about 5 to 10 inches forward of the main beam.
The repairs will be done at the same shipyard that painted/recoated the hulls. Their experience is mostly with motor boats and canoes, so they probably know less than I do about light cats. Any tip or advice explaining how to best fix this is welcome.
Many thanks for your help!
Luiz Schechter
Repair of SC15 bow broken near the main crossbeam
Repair of SC15 bow broken near the main crossbeam
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Kevin Keller
- Professional
- Posts: 363
- Joined: September 24th, 2006, 2:56 am
- Boat Make/Model: SC-20, ARC22
- Location: Honolulu
Re: Repair of SC15 bow broken near the main crossbeam
It looks like there was some delamination damage prior to the re-gelling. The yard, if they knew what they were doing, would have fixed that damage prior to re-gelling. I had some on my boat my hulls also but repaired it.
In addition, I have to wonder if they stripped the original gel coat off before they recoated it. If they had they might have ground into the fiberglass and seriously weakened the hull.
It does look like hull failed first and as the mast fell it would have put enough force on the dolphin striker to break it.
If they don't know how to repair the fiberglass/foam hull, I would NOT have them do it. I'm sure it can be fixed but it definitely needs to be done right. I would talk to Tom Haberman first and then I would query them as to exactly how they plan to do it. If there is other delamination it needs to be fixed on the inside and outside. This requires cutting holes in the hulls to gain access.
In addition, I have to wonder if they stripped the original gel coat off before they recoated it. If they had they might have ground into the fiberglass and seriously weakened the hull.
It does look like hull failed first and as the mast fell it would have put enough force on the dolphin striker to break it.
If they don't know how to repair the fiberglass/foam hull, I would NOT have them do it. I'm sure it can be fixed but it definitely needs to be done right. I would talk to Tom Haberman first and then I would query them as to exactly how they plan to do it. If there is other delamination it needs to be fixed on the inside and outside. This requires cutting holes in the hulls to gain access.
Re: Repair of SC15 bow broken near the main crossbeam
Thanks, I agree with you.
The shipyard did remove the old coat and certainly sanded the glass in the weakened part. They did what I told them to do and it was my mistake not seeing that weakened point and not asking to fix it. They thought the glass was solid, not sandwich, and so did I.
Anyway, they are the best available here and certainly better than me for the job. Their lack of knowledge is precisely why I am asking for advice: if I tell them exactly what to do they will do it right.
Cheers,
Luiz
The shipyard did remove the old coat and certainly sanded the glass in the weakened part. They did what I told them to do and it was my mistake not seeing that weakened point and not asking to fix it. They thought the glass was solid, not sandwich, and so did I.
Anyway, they are the best available here and certainly better than me for the job. Their lack of knowledge is precisely why I am asking for advice: if I tell them exactly what to do they will do it right.
Cheers,
Luiz
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Kevin Keller
- Professional
- Posts: 363
- Joined: September 24th, 2006, 2:56 am
- Boat Make/Model: SC-20, ARC22
- Location: Honolulu
Re: Repair of SC15 bow broken near the main crossbeam
Have you talked to Tom yet?
This is what I would do. You first need to make a new fiberglass layer for the inside. I think both your hulls are symmetrical so you would use the same location on the other hull to do this. On the outside of other hull I would put a piece of plastic over the area that corresponds to the damage and lay 2 layers of fiberglass (6 oz). After it hardens you can trim the repair pieces to the correct size. I think I would leave a 3 inch overlap (past the good fiberglass/foam bond) for a good bond to the old fiberglass.
I would start opening up the area of damage on the inboard of the hull to gain access. You need to restore the fiberglass that connected the foam bulkhead to the forward bow at the top. Obviously before you start rebuilding, the bow has to be lined up in the correct position. It might be easiest initially to do this with the hull upside down. I believe the hull is made of 2 pieces glued together. So the top of the hull and the bottom where they meet are solid fiberglass. You can start fiberglassing them together on the inside to hold the bow in position. After you have done this I would start repairing the inside of the outboard side. Take the repair piece you made from the impression of the other hull and bond it to the inside of the hull where the crack is. Now you have reattached the inside layer of fiberglass for that location. You need to get some new foam to replace the old foam from Aquarius. From the outside you would cut the foam to fit and bond it in. Then you would fiberglass the outside overlapping the old fiberglass. I would probably extend it 6 inches or so forward and aft of the damage. You want to about the same number of layers on the inside of the foam as the outside so that one side is not much stronger than the other side causing a shear force in the foam.
Then I would start repairing the inboard side of the hull using the same method as described above. You will probably have the bottom of the hull (where the solid fiberglass is) opened up last to have access to finish the repairs to the inside section. After the insides are done you close up the solid fiberglass area. I would really beef up the top and bottoms (where hull halves meet) from the outside extending the fiberglass a couple of feet out fore and aft.
You might have seen my other post, Refurbishing SC20. That will give you an idea of how to do some of the repairs.
I think if done right it could be good as new and you would never know it was damaged. It looked like they did a nice job finishing the hulls the first time. I hope they didn't compromise any fiberglass in other locations also.
This is what I would do. You first need to make a new fiberglass layer for the inside. I think both your hulls are symmetrical so you would use the same location on the other hull to do this. On the outside of other hull I would put a piece of plastic over the area that corresponds to the damage and lay 2 layers of fiberglass (6 oz). After it hardens you can trim the repair pieces to the correct size. I think I would leave a 3 inch overlap (past the good fiberglass/foam bond) for a good bond to the old fiberglass.
I would start opening up the area of damage on the inboard of the hull to gain access. You need to restore the fiberglass that connected the foam bulkhead to the forward bow at the top. Obviously before you start rebuilding, the bow has to be lined up in the correct position. It might be easiest initially to do this with the hull upside down. I believe the hull is made of 2 pieces glued together. So the top of the hull and the bottom where they meet are solid fiberglass. You can start fiberglassing them together on the inside to hold the bow in position. After you have done this I would start repairing the inside of the outboard side. Take the repair piece you made from the impression of the other hull and bond it to the inside of the hull where the crack is. Now you have reattached the inside layer of fiberglass for that location. You need to get some new foam to replace the old foam from Aquarius. From the outside you would cut the foam to fit and bond it in. Then you would fiberglass the outside overlapping the old fiberglass. I would probably extend it 6 inches or so forward and aft of the damage. You want to about the same number of layers on the inside of the foam as the outside so that one side is not much stronger than the other side causing a shear force in the foam.
Then I would start repairing the inboard side of the hull using the same method as described above. You will probably have the bottom of the hull (where the solid fiberglass is) opened up last to have access to finish the repairs to the inside section. After the insides are done you close up the solid fiberglass area. I would really beef up the top and bottoms (where hull halves meet) from the outside extending the fiberglass a couple of feet out fore and aft.
You might have seen my other post, Refurbishing SC20. That will give you an idea of how to do some of the repairs.
I think if done right it could be good as new and you would never know it was damaged. It looked like they did a nice job finishing the hulls the first time. I hope they didn't compromise any fiberglass in other locations also.
Re: Repair of SC15 bow broken near the main crossbeam
I just wanted o thank Tom Haberman for his advice regarding the repair procedure. The repair work took forever because it was done in the shipyard's spare time (and mine), but in the end the boat looks great and has no perceptible weight increase. It has been sailing for a few months now and even won a race. All we have to test/try now is a race with strong winds, probably next weekend.
Thanks again!
Luiz Schechter
Thanks again!
Luiz Schechter