Bow GRP repair after hitting a rock island

[gtpinhei]

Originally Posted by DeepFrz

This may help you.
WEST SYSTEM | Projects - Boat Repair

Thanks DeepFrz, I am probably going with West System. Let you guys know how it develops.

[gtpinhei]

Originally Posted by Ann T. Cate

When you get a chance to do it, photographs showing the damage will help. There are a few shipwrights who are CF members, and PM's will get a response, so there's no lack of wisdom.

Sorry about the accident; you've been fortunate, no one injured, and a good (albeit brutal) learning experience.

Ann

Hi Ann, indeed it was.

Very lucky. And a great lesson, although the hard way.

Glad we are are all well and floating, and we're able to reach Ft Lauderdale without any other problems.

Best!

[gtpinhei]

Originally Posted by UNCIVILIZED

Glad that no one got hurt, & that the boat's fixable vs. being a new artificial reef.

Um, maybe it's just me, but I can't get the pic to enlarge by clicking on it. And thus, can't offer up specific wisdoms. Well, other than "the usual", aka the reference already mentioned. Plus, if you're serious about doing it right, a core sample burn down test helps (in solid glass hulls). That, and one other iest. Call it a laminate "CAT Scan" (the true names escape me @ the moment).
I’m fairly certain that it’s something other than a thermal test. For example, the racer PRB had the integrity of the fibers in her keel structures checked with it after a grounding, prior to being splashed again for an ocean crossing.

In a burn down test, the "boat lab geek" takes a sample of the hull near the damaged area. And then it's literally burned until no resin's left, as the glass (and many other fiber types) in the extracted sample piece of the layup don't burn.

From there, an expert/lab can determine; fiber type, weight, orientation, & layup schedule. Or get pretty close to it. So that then, you can match what's there when doing the repair. And assuming that you get the resin right, between that, & the fiber matching (weight, weave or stitch pattern, & type), it's an almost perfect clone of what was there, pre-impact.

All of this is, after, of course, you get someone to do some fancy tests to tell you how far the damage is, beyond what the eye can see. IE; some NDT to tell you how big the "owie" is. As unlike say, sheet metal in a car, damage in composites can spread out far further (sometimes) than meets the eye (is visible).
The "CAT Scan" part/tests.

Ah, & of course, both of these tests are Far from cheap. And the 1st one especially, is usually reserved for boats with laminates that are rather svelte when compared to a boat's size. And or, she's made with semi-exotic fibers, & a layup designed with FEA/Load Path Mapping (like in a "string sail").
These kinds & levels of testing are done when for some reason, the original layup can't be tracked down via the builder, but the above, fancy construction methods are known to have been used.

Although, as a reality check. Unless you're super concerned about rebuilding to as new status, there are simpler fixes which are plenty strong. But one has to be able to see, and know, what they're working with.


PS: Using the right resin(s) is also vital. Both in terms of strength, & in that some resins don't stick well to some other cured ones.

Plus, ideally, you want to match the physical strength, & flexural characteristics of a resin to that of the reinforcements that you're using. As different brands & type of glass (and other reinforcements) can have vastly differing physical properties. Even though in essence, & in labeling, they're the "same thing".
IE: Quite literally, one can be more than twice as strong as another. Much as the "same" alloy of a steel from 2 different smelters can have vastl differing properties.

Uncivilized, you make me rethink if I should go with West System or Polyester resins. My Hull is supposed to be Polyester... as the boat is new to me (2 months), I am not pretty sure.

Wrote to Van de Stad design office but did not get much help, they do have construction plans which I intend to buy in order to get it fixed right.

Let's see how it develops as I haUl it out.

I'll look at the tests, but considering it's a 35 years old boat, I believe the most important is maybe not only match original lay up but add even more layers (and it seems to already be very thick), kind like in pre-computer days. In doubt, make it stronger (although heavier).

Best

[dgz3]

I don't know Minaret from Adam, but I completely agree with his advice! I think you will be time and money ahead, provided you can find a truly competent and honest pro. And that may be harder than you think. Especially in South Florida which suffers from "a pestilential abundance of low lifes and scum bags..." many of whom have "Boat Repair" signs on their pick up trucks.
Once you get to grinding that out you will be shocked at just how much damaged laminate you have and at the size of the hole you will wind up with! This is a much bigger repair than it looks like.
And anything less than a completely (read invisible) repair might seriously devalue your boat at sale time, thus negating any savings from doing it yourself.
No offense intended, but the fact that you are even here asking how to do it is proof positive. I say, "Seek professional help."

[Cadence]

I also would tend to agree with minaret re: getting a pro.. It is going to be a major job far more than putting auto body filler in and fairing. Not inferring you would do it that way but vet anyone calling themselves a pro.. I have build a glass 48' from the strongback up, all glass, and would have to give doing that repair a second thought.
JMHO

[chris95040]

Originally Posted by gtpinhei

Uncivilized, you make me rethink if I should go with West System or Polyester resins. My Hull is supposed to be Polyester... as the boat is new to me (2 months), I am not pretty sure.

Wrote to Van de Stad design office but did not get much help, they do have construction plans which I intend to buy in order to get it fixed right.

Let's see how it develops as I haUl it out.

I'll look at the tests, but considering it's a 35 years old boat, I believe the most important is maybe not only match original lay up but add even more layers (and it seems to already be very thick), kind like in pre-computer days. In doubt, make it stronger (although heavier).

Best

Your hull probably is polyester, but that doesn't mean you should stick with polyester. I'd try and somewhat match the original layup in terms of fiberglass, but you almost certainly shouldn't use polyester as your resin.

Polyester is fine for parts that are made all at once, where the polyester resin can all be chemically crosslinked since it all cured together.

When making repairs, however, I think you want to go with epoxy. In the case of repairs, you are adhering your new material to existing, already-cured, inert old resin. Epoxy bonds to existing, cured polyester resin _way_ better than polyester would.

I also try to construct repairs such that there's more than just adhesion holding the old stuff to the new stuff, that the old + new are somehow mechanically keyed into each other. I like it when I look at a repair, and consider if the entire bond between the old + new stuff failed, and realize it would still be held together mechanically. Not because I think a properly executed repair will have that problem, but because I think the whole thing seems stronger and more impact resistant this way. Plus it just gives me that warm and fuzzy feeling, which is what sailing is all about.

[gtpinhei]

Guys, I was responding to other posts as I perceived I had not submitted updates to this anymore.

First sorry for all that contributed to it.

Well, so here it goes an update. As I could not stick in Florida for long, I decided to do the repair myself using West System.

I grinder all part that was damaged and took out almost 1/2 inch in some parts until I found no more cracked material.
I also confirmed that there was a previous repair in the same area, which was not as well done as I found a lot of filling material, probably epoxy with fiber spheres as it was softer than epoxy itself, and responded to grinding in a different way.

I also removed all this filling material.

After grinding, and acetone cleaning I started layering fiber and epoxy in overlapping layers following the tension and power vectors applied to the bow.

Instead of the 2 weeks asked by recomended fiberglass professionals in Ft. Lauderdale, the entire work took me around 4 days.

The major difference is that I worked both during the day and night, as It was in my best interest to finish it and leave Lauderdale north as soon as possible.

I did not hire the expensive high tech tests. My boat is old school so I kept it to how it was made.

I also did not finish the gel coat in the outside, only painted it white.

I also added layers of fiber and epoxy on the interior, further reinforcing it as I believe it would have been done when the boat was built.

We left Ft. Lauderdale and sailed to Beaufort, NC; Norfolk, VA; New York and finally reached out final destination, Boston.

We faced 2 bad weather situations on the way and sailed through it without any problems.

We have been sailing around Boston and went to Maine for a couple weeks when we had a break from school and work.

The boat has been behaving perfectly and I must say I trust very much the work I have done. It was also great to learn how to work with fiberglass.

Took me time studying it and drafting how I would repair it. It was great learning and now I feel I am capable of doing other repairs if I need in the future, and so be even more self suficient aboard.

I also ended up with a lot of epoxy and fiber as I found cheaper to buy it in bigger quantity, so I plan on some fiberglass projects.

My wife took some pictures of the repair and I will post it later.

After the winter I will probably do a new bottom paint and than it might be a good opportunity to refinish the gel coat. But this will be next year.

Best

Gus


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[JPA Cate]

Thanks for coming back and telling us what you have done.

Ann