Best fix for small damage in hull

[Cadence]

Originally Posted by sune

Hello everyone,

I'm a new boat owner so forgive me my newbie questions.
I bought a fine old 24 foot sail boat here in Copenhagen, Denmark.
It's a Bandholm24, fibreglass hull, built in Denmark in 68.
She's mostly in good shape but not entirely.
Attachment 158891

My first question is regarding some damage in the bow over the waterline.
Looks she took a beating by the dock.
Attachment 158889

- What's the best fix here?
- Should I grind around the holes, clean with acetone and then fill with epoxy?
- This is this gelcoat, right? (I'm new to fibreglass but learning)

- I think the hull is solid fibreglass all the way through, I don't think it has a wood or foam core. Does that sound right for a 68 construct?
(displacement 4850 lbs., ballast is 2425 lbs.)

Thanks in advance

Are they holes or just abrasions? It's hard to tell from the pic.. Circa 68 she is probably heavily laid up solid glass.

[sune]

Just abrasions, no holes going through.
I'm pretty certain now that the hull is solid glass.

Beneath the gelcoat, I can see what looks like very coarse woven fabric. I suppose that's coarse fiberglass.

[Cadence]

Originally Posted by sune

Just abrasions, no holes going through.
I'm pretty certain now that the hull is solid glass.

Beneath the gelcoat, I can see what looks like very coarse woven fabric. I suppose that's coarse fiberglass.

Just abrasions, and down to the woven roving. Feather it out and fill with an epoxy filler. It doesn't sound structural. Just seal it so the roving won't wick water if not fully saturated originally.

I'd bet you have a great hull.

[barnakiel]

Originally Posted by sune

(...)

- I think the hull is solid fibreglass all the way through, I don't think it has a wood or foam core. Does that sound right for a 68 construct?
(displacement 4850 lbs., ballast is 2425 lbs.)

Yes. Solid. Not to be mistaken with heavy.

Scandinavian boats, even the old ones (60-70), were not typically heavily built. Nor were old grp boats built at that time elsewhere, when they were designed by good architects and built by competent boatyards.

Few boats of that era were balsa or foam cored. Laurins, yes, but otherwise few. Balsa and foam decks and cabins were common though, from about 1970 onwards.

Even cored hulls will have HUGE amt of glass at the bow. At times an inch or so.

You can compare your hull to this UK boat:

TRIDENT 24 sailboat specifications and details on sailboatdata.com

You will quickly discover the shell is about the same weight.

The rowing will be the second or third layer from gelco.

I may be corrected by someone more competent but I think the layup back then was: gelco, mat, mat, rowing, mat, rowing, mat.

I have also seen some boats finished in rowing inside (e.g. Naoglass built Pumas, NZ built Ravens, etc)

Cheers,
b.

[Suijin]

The first thing I would do before anything else is to compound/polish the entire top sides to see what your working with. The green gelcoat is faded and chalked, and polishing it to a shine will not only help protect it a bit going forward but will also reveal the color you want to match if you want to make a repair.

Matching gelcoat is a time consuming process if you want a close match. And the patched area will fade at a different rate than the rest of the boat.

That said you can fix it or leave it. It looks like accumulated dock rash. If it were me I’d go sailing and leave it for when I was contemplating a bigger renovation.

[Bluebeard]

I don't often post on here because so much of yachting lore is opinion posing as fact.
But I do know a bit about repairing GRP hulls, mainly dinghy hulls but they are built in exactly the same way. With dinghies my golden rule is if it is painted walk away, the paint can hide any bodge. Unpainted GRP is very honest.

Your photograph looks as though it is just gel coat damage, if you can see the glass where there are scratches that is not a problem as long as there are no cracks in the underlying structure. That is something that you must determine for yourself. At that position in the hull, as others have said, the lay up will be very thick and it is unlikely to be damaged. Lets assume for the moment that there are no cracks.

To repair damaged gel coat or to replace gel coat on top of a more serious repair you need,
Acetone,
Gel coat resin,
Catalyst,
Solution MW / Wax Additive for Gelcoat
and pigment.

Any good material supplier will sell it all, and it should come with resin /catalyst ratios. I find it is not critical but I shall probably be shouted down

It will do no harm to lightly sand the area you are about to repair.
But before you apply your new gel coat you MUST clean it thoroughly with acetone ( possibly other solvents but I always use acetone )
Mix your gelcoat resin with the correct amount of catalyst, your pigment, and a little Solution MW, about 2% of this.

Apply in a thin layer, if you are patient enough so it doesn't run the rest of the process will be easier. When it is set, clean again with acetone, and apply another layer, repeat until you have built up the required thickness.

It may help to sand the repair between coats, especially if you have new gelcoat where it isn't needed. Then sand with progressively finer paper till you have a good smooth repaired surface.

Some key points, for most small repairs you will only need a very small amount of gel coat prepared. And a new batch for each coat.
Gelcoat is formulated so that it won't set unless air is excluded. This is what the Solution MW does, it forms a surface film to exclude the air from the gel coat.

As others have pointed out matching the colour may be difficult. Various manufacturers have ranges of pigment colours and you may be in luck and have a passable match with standard colour, otherwise you will have to mix up what you want. I have never succeeded in buying small quantities of pigment, so you end up with far far more than you need.

If you haven't done it before mix up a batch and apply it on something that is scrap. That way you can see that it is working right before you put it on the hull.

If you decide that you have structural damage let me know and I will write you a layman's guide.

[sune]

Thanks very much for all the answers and guides! That's incredibly helpful!

You all point out that it's a very small damage in the gelcoat, so nothing to worry too much about.
I'm not sure yet but I think I still wanna do a repair before she goes back in the water, if nothing else then just to try some gelcoat work.
I don't know yet if I will go all in with colour matching or just use a filler.

I'm thinking there won't be any water intrusion and damage during winter.
She's been sitting on land like this since summer 2016.
Or do you think I should fill the cracks now before winter?

There's a few other spots around the topside that could use a little gelcoat.
Here's another little crack.

To me it looks like the woven roving is the very last layer before gelcoat, maybe I just can't see the glass layer that might be in between.

I will definitely compound/polish the topside.
Would that be fine to do now or should I wait until spring?
Temperature in winter in Denmark could drop to 20F, but mostly it's a little over freezing point and wet and windy (+ dark and miserable :-)

Thanks again!

[valhalla360]

Judging by the pictures it's just cosmetic damage. The question is how much effort you want to put into it.

Options:
- Just leave it alone. It's probably been that way for years and likely won't get any worse. If it does, it's easy enough to fix it later.
- Do a bit of grinding/sanding and then fill with gelcoat. Lots of online directions. As mentioned near impossible for an amateur (and many professionals) to get an exact match. You will always see the repair area.
- Do a bit of grinding/sanding, fill and then paint the topsides (use a single part marine enamel roll & tip. the high end 2 part paints sprayed on professionally are cost prohibitive). It's clearly more work but the whole boat will look so much better and it's a manageable DIY project. With 50yr old gelcoat, getting and keeping it shiny is often more effort than just painting.

FYI - A vote for Epoxy if you do find structural items that need to be addressed. As long as you follow the directions, it's easy to work with and sticks to anything. Google "West System" they have lots of free literature detailing how to do various projects (even if you use a different brand).

[barnakiel]

When woven rowing is just below gelcoat, you will often see a print-thru (rowing pattern) when the gelco is polished and buffed - just look at a narrow angle, sighting along the topside.

I have seen not just rowing but also the sandwich (foam or honeycomb) print thru on a completely new boat last year. If I recall well, boat brand Azzure or something like that. Built nowadays in E Med. Amazing, but I am not sure this is what the designers envisioned ! ;-)

Cheers,
b.

[twohapence]

Presumably you bought the boat because you want to go sailing and have a target lift-in date?

I suggest you put together a to-do list and a timetable with the aim of getting your boat in the water. You'll want to take the sails off and inspect them, possibly have them washed and serviced. You may want to take the various lines off, wash and inspect them and replace any that are obviously unserviceable. Then there's the engine and gearbox check and service. Scrub down the hull. Antifouling. Electrics. Battery and battery charging. Through hull fittings inspection. Anode inspection and replacement. And so it goes. All of this takes time and money.

You also want to have fun with your new boat so doing hard stuff in miserable conditions isn't going to be top of your list. You're also going to be inside your boat looking out when you're on the water. How much of the hulls can you see from the cockpit?

I'd concentrate on the basics. Worry about the cosmetic stuff later so you can get out on the water and enjoy your sailing.

Two.

[twohapence]

Oh, and prioritise........You'll be amazed how much stuff on a to-do list gets carried over to the following winter. :-)