Hobie 18 Top Sheet Repairs

Hello,
I have a 1972 Hobie 18. This is my first boat, and my first rebuild. I got it cheap, and now I need to fix it or it will get parted out, which would be a shame. My issues to deal with are keel repairs (I can see glass on the bottom), dagger board sleeve reinforcements, and major top sheet reinforcements. I only need to keep this thing working, but not to show quality standards.
The biggest problem I have is my top sheets. You could say the entire top sheet is a severe soft spot. When sailing it, if you sit on the hull, it compresses a inch or two below the rails of the hulls. I know people talk about injecting West Marine as a solution. I think this concept would not solve my problems, since its' on such a large scale. My current plan is to sand off the current gel coat on the top sheets (which is cracked, and old). Prep the surface, and then I want to lay a couple layers of glass from one end of the boat to the other. Then I plan on putting a new gel coat down. I know this is going to add a lot of weight ,but I can't come up with a better way to save these hulls. My keels I think will be fairly simple. Sand off the chipping gel coat, prep, more gel coat. Being that the fiber glass has been exposed and worn into, should I reinforce this somehow before more gelcoat? Lastly, my dagger board sleeves are delaminating from the dagger board collars. I think I can reach down there and get some epoxy to do the trick. Any suggestions for this repair? I was also trying to think up of ways to beef up the dagger board system in general. Any help would be greatly appreciated. I feel plenty competent to jump into this on my own and come out with a good boat, but there's no sense doing things the hard way. I would rather do it right, with your advise.

Thanks,
-Sam

Whitefish, MT

The deck structure would not be improved... much... by adding layers on top. The inner layer and outer need to be bonded. That is the job of the foam. I would first try a delamination (resin injection) repair. Second, you could cut the top sheet off the boat, scrape out the damaged foam and fill with glass or sheet foam and re-laminate the deck on top of that. The top could be cut just outside the nonskid line and peeled off.

The dagger wells sound repairable as you described.

The bottom repair is straight forward. It is quite common to see glass where the gelcoat is worn off from dragging the boat over sand. It takes a very long time to wear through it, but layers of glass could be laminated to the bottom to build it up a bit.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

With one hull I have all ready sanded off the gel coat. The gel coat was in bad shape from one end to the other. There is evidence of someone else's poor injection repairs. I think they used spray foam, as it can be seen in the layering when the inspection ports are removed.
I can now easily see exactly where the foam is inside the boat. I like your idea of removing the foam and filling the space with fiber glass. Is the only advantage of foam the weight savings? It seems harder to make it secure.
How close can get to the dagger board collars? Anything I need to consider with them?
The top sheet pieces I would cut out don't seem worth reusing. They will have holes, thin points, perforations etc. After filling the spaces, should I lay new glass across the top, or first lay the original sheets back down, and then patch it together? While it is all sanded down and exposed, would you recommend I do still lay some glass across the whole top of the boat? It seems like this would be a good way to seal up and hide my work.
Also, when I work on the keel. Do i need to remove all of the thick gel coat that that covers the keel before I add glass, or should I just remove the chipping gel coat on the bottom and put glass on the bottom only?

Thanks,
-Sam

Yes, the foam sheet allows a stiff construction (I Beam) without the weight of solid glass.

The foam tapers to solid glass along the rails and near the dagger wells. No sure how to tell you how close. May be trial and error (hope for no error).

Yes, remove all gel coat. Get a glass to glass bond.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Must be newer than that. The Hobie 18 started production around 1978.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Thanks for your help,
You are right, it's a 1979. (been awhile since I've looked at the title).
So, I have carefully cut off the top sheet, using the foam as a guide. I took a putty knife and then removed all of the foam (didn't take much effort, seems like the glue has bee failing for awhile).
Now for filling it. The foam option seems a bit trickier to shape and install than I'm in to. I was considering either filling it with stacked fiber glass, or maybe just filling it nearly to the top with west marine epoxy, then glass.
Can I expect glass to adhere to epoxy?

Ideas?

Thanks for your continued help!

Use glass. Solid epoxy will simply crack.

Epoxy will bond, no problem. Be sure to sand well.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

I've often thought that removing the deck skin and re-coreing it would be a pretty legit fix for delam. Lots of steps involved though. Send some pics of your progress. If you can't post them here, send them to me and I'll post them.

_________________
Sail Revolution
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Oh and a little trick that may work on the dagger board wells:
Use a shop vac attached to the drain plugs to suck epoxy deep into the cracks in the board well, that way you get a better bond. You'll have to regulate the pressure manually.
J

I work on the road, and will return home shortly. When I get back, I will take pictures of my boat as I go along, and post them for you to see. Thanks for the pointers.

Any recommendations for fiber glass? There's a lot out there. I was hoping someone might have found a specific product that is both affordable and functional. Preferably with a mat that is thick, and can fill the space with minimal layers.

Thanks.

Also,
There's a lot of opinions of whether to go with Epoxy or Vinylester with my mat. I know Vinylester will be easier to gelcoat, but epoxy is so strong. Also, which product should be used for the keel repairs?