Gelcoat crack question

MichaelB1969 · Sep 15, 2017

First off, for all those affected by the storm, my heart goes out to you.

I've got a big area above the chine with gelcoat cracks. From the looks of it, seems like something impacted the center of this area, but I don't recall hitting anything that high above the chine. We would have noticed it in the water.

I did recently strike something under the water on two separate occasions a few weeks ago heading down to Monterey where we felt a thud and an accompanying sound beneath us. No idea what they were. But again, this was under the waterline for sure.

Any thoughts?

P.S. I still haven't talked about my diesel fuel episode from that trip where water started gushing up from the tank. I'm still traumatized. Need more time.

psneeld · Sep 15, 2017

Without grinding off the gel coat, hard to tell how bad it is.

Can you see the area from the inside?

If you can, place the brightest light you can on the outside and take a picture from the inside.

MichaelB1969 · Sep 15, 2017

Next time I'm on the boat I'll poke around and see if I can access the other side. Thx.

hfoster · Sep 15, 2017

psneeld said:
Without grinding off the gel coat, hard to tell how bad it is.

+1.

Also take a strong light and check for small spider cracks on both sides. The cracks can be very fine, so look carefully.

Best of luck Mate.

Cheers.

H.

DHeckrotte · Sep 15, 2017

First thought: talk with Beneteau. If they're anything like Island Packet, they'll have excellent customer service. Could be a fault in the layup.

Second thought: ignore it but monitor it. Spreading? Chips falling off? I've got a couple small, 3" x 6" areas, of gelcoat failures on the 33-year-old house sides and I'm watching 'em.

If no service and confidence that things are getting worse, then grind it - have it ground - off to apparently decent/sound 'glass and do the repair. The repair, I think, should include 'glass.

Dad's '72 Morgan 27 was improperly loaded on a trailer when new. The cracks in the gelcoat where the cradle bore where there was no interior structure never got worse but were visible for the 35 years we had the boat.

FF · Sep 16, 2017

Cracked gel coat comes from the underlying GRP flexing too far.

Frequently the flexing damages or reflects damage to the underlying GRP .

At a minimum you will need to access the hull in the area to see what damage there is.

Repair/ stiffen with epoxy laminates not Polly.

Bacchus · Sep 16, 2017

FF said:
Cracked gel coat comes from the underlying GRP flexing too far.

Frequently the flexing damages or reflects damage to the underlying GRP .

At a minimum you will need to access the hull in the area to see what damage there is.

Repair/ stiffen with epoxy laminates not Polly.

I would agree w FF...on both counts...inside important and epoxy vs poly

I did a repair of an external gel coat crack but after discussion w a "fiberglas repair guy" we spent as much attention to the inside as the outside.
Reinforced the inside and tapered the reinforcement to avoid an abrupt change in stiffness that would tend to concentrate stress from any future deflection.

MichaelB1969 · Sep 16, 2017

Thanks for the tips everyone. I have a Gelcoat repair guy who is going to fix a bunch of cosmetic stuff, mostly around the cap rail. I'll have him take a look and will recommend epoxy for the repair.

psneeld · Sep 16, 2017

MichaelB1969 said:
Thanks for the tips everyone. I have a Gelcoat repair guy who is going to fix a bunch of cosmetic stuff, mostly around the cap rail. I'll have him take a look and will recommend epoxy for the repair.

A pro may use poly or vinylester for a repair.

The new formulations are pretty good if you use them correctly.

Some vinylesters rival many epoxies for strength and water resistance. Not the top of the heap, but not a joke anymore either.

So if he discusses it, don't take it as poor workmanship or cheaping out..

BruceK · Sep 16, 2017

FF said:
Cracked gel coat comes from the underlying GRP flexing too far.

Frequently the flexing damages or reflects damage to the underlying GRP.....

Sounds right, wonder why is this happening? Damage, impact, or construction?
How thick is the hull? Do the comments on TF about wave slap reflect hull thickness? I`ve been on Beneteau Swifts at Boat Shows, I weigh around 80kg,as I walked around the boats it seemed they moved/listed following my movements, not something I experienced on other Show exhibits.

MichaelB1969 · Sep 16, 2017

BruceK said:
Sounds right, wonder why is this happening? Damage, impact, or construction?
How thick is the hull? Do the comments on TF about wave slap reflect hull thickness? I`ve been on Beneteau Swifts at Boat Shows, I weigh around 80kg,as I walked around the boats it seemed they moved/listed following my movements, not something I experienced on other Show exhibits.

Well, it could have happened when I struck the objects on our way to Monterey, who knows. Not sure about the 34 Swift, but my 44 does not move at all when I walk around and I weigh 200 lbs. That said, the Swifts are relatively light boats which is one reason they are fuel efficient. My boat weighs 24,000 lbs dry.

Hull is likely thick enough but it's cored I believe, not solid. In any case, they've been building boats for over 100 years and have a very healthy R&D budget, so I'd imagine they generally know what they're doing.

We have not been in heavy seas so my assumption is we hit something.

MichaelB1969 · Sep 16, 2017

For what it's worth, this is what the brochure says about the hull construction. Can anyone translate this into English for me?

HULL
Composition:
• Sandwich (polyester resin - fiberglass / balsa core)
• White gel coat
• Structural hull counter molding in monolithic laminate (polyester resin
- fiberglass)

CaptSteve53 · Sep 17, 2017

MichaelB1969 said:
For what it's worth, this is what the brochure says about the hull construction. Can anyone translate this into English for me?

HULL
Composition:
• Sandwich (polyester resin - fiberglass / balsa core)
• White gel coat
• Structural hull counter molding in monolithic laminate (polyester resin
- fiberglass)

Michael, as below -trying to keep it simple here,

1) Sandwich- means Polyester skin(and matting) on the outside and a core/middle layer of Balsa wood) covered again on the inside with another layer/layers of Polyester resin (and matting),

2) White Gel coat is a colored polyester resin applied to the boat mold in the first instance to give you the color, Goes like this when laying up a hull,
Wax the mold
3)Apply the Gel coat
4)Apply resin and mat.cloth-(many today use chopper guns that mix the resin and the mat/cloth and sprays on)
5)Apply the balsa core in the area's as required/specified
6)Apply more coatings of resin/cloth /mat again normally done with the chopper gun-More expensive boats are hand laid and dont use the chopper Gun, hand laid can produce a lighter/stronger hull, then there's vacuum bagging, usually stronger and lighter again,

“Monolithic” fiberglass construction is a fancy name basically for using the better materials and doing it right such as:

“Monolithic” construction methodology is unique to the industry and is founded on three pillars. First is the human element already noted. The other two are premium materials and a specific method of construction based on sound engineering, industry support and a rigid quality control system.

Vinyl ester resins today are a very good alternative to Epoxy resin if repairing a GRP vessel-Dont get me wrong Epoxy has it's place especially in repair work but many professionals will prefer to use a Vinyl ester (nothing wrong with that!) Many higher quality vessels use Vinyl Ester as the norm,

Cheers Steve

BandB · Sep 17, 2017

Are you seeing spidering anywhere else on the boat, perhaps the deck?

MichaelB1969 · Sep 17, 2017

BandB said:
Are you seeing spidering anywhere else on the boat, perhaps the deck?

Yes, but very minor compared to this. Mainly in 3 or 4 spots where the hull meets cap rail. The gelcoat guy thinks it's from the screws that attach the cap rail to the hull.

MichaelB1969 · Sep 17, 2017

CaptSteve53 said:
Michael, as below -trying to keep it simple here,

1) Sandwich- means Polyester skin(and matting) on the outside and a core/middle layer of Balsa wood) covered again on the inside with another layer/layers of Polyester resin (and matting),

2) White Gel coat is a colored polyester resin applied to the boat mold in the first instance to give you the color, Goes like this when laying up a hull,

Wax the mold

3)Apply the Gel coat

4)Apply resin and mat.cloth-(many today use chopper guns that mix the resin and the mat/cloth and sprays on)

5)Apply the balsa core in the area's as required/specified

6)Apply more coatings of resin/cloth /mat again normally done with the chopper gun-More expensive boats are hand laid and dont use the chopper Gun, hand laid can produce a lighter/stronger hull, then there's vacuum bagging, usually stronger and lighter again,

“Monolithic” fiberglass construction is a fancy name basically for using the better materials and doing it right such as:

“Monolithic” construction methodology is unique to the industry and is founded on three pillars. First is the human element already noted. The other two are premium materials and a specific method of construction based on sound engineering, industry support and a rigid quality control system.

Vinyl ester resins today are a very good alternative to Epoxy resin if repairing a GRP vessel-Dont get me wrong Epoxy has it's place especially in repair work but many professionals will prefer to use a Vinyl ester (nothing wrong with that!) Many higher quality vessels use Vinyl Ester as the norm,

Cheers Steve

That's great information Steve! Much appreciated!

BandB · Sep 17, 2017

MichaelB1969 said:
Yes, but very minor compared to this. Mainly in 3 or 4 spots where the hull meets cap rail. The gelcoat guy thinks it's from the screws that attach the cap rail to the hull.

Could be. However, some builders have issues with gelcoat spidering. Some of it has been attributed to climates and conditions when built. I know one UK builder with a history of issues (although seem solved now) so for a French builder to have them also wouldn't surprise me.

I would speak to Beneteau and perhaps they'll arrange for someone knowledgeable of their boat to look at it.

BruceK · Sep 17, 2017

Maybe checking out how well the Beneteau sailboat hulls age could be informative. They`ve been around longer than the trawlers.

CaptSteve53 · Sep 17, 2017

MichaelB1969 said:
That's great information Steve! Much appreciated!

Michael,

Below is a picture of a balsa cored boat with an issue, Balsa was the norm in earlier boats to provide a lighter basically stronger vessel, they have issues quite often in area's surrounding thru hulls where the ingress of water rots and softens the Balsa causing further issues, Balsa is still used some times in deck construction, but a lot of vessels now use dedicated water resistant composite core materials such as DIVINYCELL,

The picture shows in detail the layers from the gel coat through to the interior GRP skins,

Cheers Steve

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