Cracked hull

[SailorHunter]

Hello to forum members. I am new to forum. I just bought a used Hunter 90. The hull has several long cracks. I am aware this is an issue with these boats. I was wondering whether I can cut away the outer plastic or composite shell completely, as I feel it is not worth repairing.

There is a thicker layer below this plastic shell. After removing outer shell, If I coat that inner sandwiched material with waterproofing layer like flex seal or similar coating, will that work ? My intention is to use this boat for a couple of years during the summer and then discard it, as the boat has been used extensively and is on its last legs. I feel the inner layer is what gives structural strength and buoyancy to the boat, and the outer cracked composite shell is mostly cosmetic and also for keeping water away from inner material. I could be wrong though.

This topic may have already come up earlier. If so a link will be greatly appreciated.
Thanks for your help.

 

[kappykaplan]

Welcome to the forums!
@Crazy Dave Condon should be able to help.

 

[Crazy Dave Condon]

@SailorHunter

can you take some photos of the cracks and post them here and go from there. I demorder the first one made as a dealer
Crazy dave

 

[SailorHunter]

Thanks for the replies and welcome.
I am attaching a few pictures as suggested by Dave.

As I mentioned earlier, I would prefer not to repair the cracks ( and instead consider my options after removing this outer laminate or composite shell altogether.)

2 reasons for this approach. First off, there is a lot of crack to work through. About 12 feet in all.
Second, even if I manage to patch it all up, ( that is a big IF ), the next crack is only a few days or weeks away.

I looked through the centerboard case or slot for daggerboard, to see how thick the hull wall is. It looks about 1 inch thick.That probably means the core is about 5/8 or a little more thick closer to 3/4 in.

One option to consider is removing the outer laminate and re-covering the outside of the core with 1/8 in marine ply. That is a lot of work and the fitment/ mating etc may prove more intricate and daunting than it initially looks.

That is why I was leaning towards removing the outer laminate and waterproof-coating the inner core and see if that is adequate for a few rounds of sailing.

Thank you.

 

[Davidasailor26]

Unless the Hunter 90 is different from most composite laminate construction I’d expect the skin to be an important part of the structure. Usually the strength of the sandwich comes from the outer layers. The core is there to hold the layers apart at the appropriate thickness. A piece of foam by itself has very little strength. Use it to separate two layers of fiberglass and the fiberglass can carry a large load.

 

[DArcy]

the boat has been used extensively and is on its last legs.

I think that boat's last legs gave way a while ago. You're right, it's not worth repairing. I hope you didn't pay much for it, but whatever you paid it was too much.

 

[SailorHunter]

Unless the Hunter 90 is different from most composite laminate construction I’d expect the skin to be an important part of the structure. Usually the strength of the sandwich comes from the outer layers. The core is there to hold the layers apart at the appropriate thickness. A piece of foam by itself has very little strength. Use it to separate two layers of fiberglass and the fiberglass can carry a large load.

That makes sense.

The core is visible partially through cracks in the laminate. I probed the core gently by inserting a flat tipped screw driver. The core is not very hard, but not too soft either. It cannot possibly withstand impact loads from underlying objects /rocks etc. That makes an outer shell a necessity.

Next related concern was the outer shell is separate from the inner core, at least in areas adjacent to the cracks. I assume the outer shell should be glued on to the inner core.

To fix this, I could pour some non-viscous penetrating epoxy ( like the one used to seal marine wood ) into the cracks so that the epoxy spreads out and fills the gaps if any in between core and the outer shell. Just a thought.

 

[SailorHunter]

I think that boat's last legs gave way a while ago. You're right, it's not worth repairing. I hope you didn't pay much for it, but whatever you paid it was too much.

The boat is in fairly OK condition except for the outer shell of the hull. The top fiberglass of the hull does not have any cracks or dents ( sure, it could do with some TLC ).

The mast, boom, fiberglass coated rudder, tiller , wooden daggerboard etc are all in good shape. The sail is also in good condition, though it has seen some use. Just the cost of these accessories will easily cover the $ 150 that I paid for the boat. (Paid another $ 20 for a small dolly.) I assumed that I was just purchasing the accessories. The boat itself is a gamble, but it came free.

Attaching a few more pictures.

 

[SailorHunter]

Forgot to mention, the inner core appears to be intact, from whatever was visible in between cracks. At one point where two craklines meet, the outer shell can be lifted about an inch to enable a closer look. The core looked good to me.

 

[Davidasailor26]

I feel like the ideal solution would be to remove the delaminated surface and lay up new class, properly adhered to the core. That might be more trouble than it’s worth for that boat though. I don’t know what kind of strength you’d have just trying to epoxy the shell back down to the core. Maybe it’s good enough?

 

[Crazy Dave Condon]

I have followed this thread but now need to respond. First, the construction is a molded 3/16 inch plastic sheet that is molded with construction foam. On the backside is 2-3 layers of fiberglass which is adhered to the foam with Plexsus.

Forget using epoxies as they will not adhere to plastic. The use of resin and hardner will not work. If you think using acetone on any of the materials on that boat is not recommended either. Cutting complete holes or removing plastic pieces is not the answer.

I will be glad to talk with the poster but he should know there will be costs and a lot of work. Otherwise I suggest deep six that boat

 

[SailorHunter]

Dave, thanks for your opinion which is surely helpful. I will keep your advise in mind while deciding next course of action.

 

[SailorHunter]

I saw the label JY Boats affixed on my boat. Did a web search and came up with the link shown at bottom. I have pasted below a few relevant paras regarding construction of this boat :

Quote:>>>>>
Florida-based Luhrs Marine Group, parent of Hunter Marine, announced on November 26 (2001) the acquisition of controlling interest in JY Sailboats of East Lyme, Connecticut.

JY Sailboats is producer of Plastic Composite Technology (PCT) sailboats from 2.4 to 6.4 metres in length. PCT is a patented combination of a special plastic, fiberglass mat and injected foam that chemically bonds into a durable and highly finished structure. The end product is ultraviolet protected and five times more impact-resistant than traditional fiberglass, said the company.

This thermoforming process can be utilized in many marine areas, including manufacturing boats, hardtops, motor box covers and even head liners.

JY Sailboats has been making, under license, four models for Hunter Marine. Hunter has marketed and distributed the boats under the Hunter brand and through the Hunter dealer network. JY builds, markets and distributes the JY Club Trainer and JY 15 under sailing's one-design rules.
<<<<<<<. Unquote

Luhrs Marine Acquires JY Sailboats - boats.com

Florida-based Luhrs Marine Group, parent of Hunter Marine, Silverton Marine, Mainship Corp. and Luhrs Corp., announced on November 26 the acquisition of controlling interest in JY Sailboats of East Ly

www.boats.com

 

[DArcy]

bonds into a durable and highly finished structure.

Durable? Maybe not.

Is this one of the boats that brought about the end of Hunter? Hunter was doing really well after restructuring in the early 90s, making some very nice boats. It seems they invested in some questionable technology.

 

[Crazy Dave Condon]

The article is correct. Hunter purchased JY Sailboats. What I know came from the owner of JY before the purchase. I advocated for fiberglass built boats

 

[Davidasailor26]

Thanks for chiming in @Crazy Dave Condon. Clearly this model’s construction means the repair procedures need to be a little different from a typical fiberglass composite boat.

 

[stickinthemud57]

I own a boat (Hunter 170) built using the same technology. Luran outer layer, foam, then fiberglass inner layer.

Removing the outer coat? No. This would be WAY more work than fixing the cracks, would expose the core foam to moisture and deterioration, and rob the boat of about 40% of what structural integrity is has at this point.

I would agree that the boat is probably not worth the cost and effort of doing actual "repairs" to. Plexus two-part adhesive is the ONLY proper material and is pretty costly.

My advice? As long as it floats, and as long as you accept and are prepared for the possibility that it may become un-sailable in mid-cruise, then I say apply some band-aids and get your $150 worth. Seal the cracks with a sealant that will bond to plastic. Buy and ALWAYS wear some good life jackets. Sail in protected, populated waters where waving down help and/or paddling to shore is a viable option. If treated as a floating toy, you could have some fun. EDIT - BRING ALONG A FLOATING HAND-HELD VHS RADIO.

It looks to me like this boat will float "for now", maybe even for the rest of the summer. Beyond that, most likely not. Band-aid patching such as I have suggested will NOT help the structure and most likely NOT prevent eventual waterlogging of the interior foam. No matter what, the cracks will get bigger and eventually the boat will become un-sailable. Ditch it before that happens, but go ahead and use it much as you might use an old, decrepit car. Beach it with impunity. Don't worry if it bumps against the dock. If it slips off the trailer, what the heck. This might be a great first boat, where no harm you do to it will illicit more than a good laugh as long as it does not fall on someone's foot.

I would say if it gets you through the summer, money well spent. Go in with no expectations other than that it will fail unexpectedly.

Your experience with this boat will be helpful in determining what your next boat will look like.

 

[Will Gilmore]

http://www.nautline.com/sailboat_plywood_plans.php#N350
The Naut350 looks like a great project to put all that great hardware and rigging to use on.
Or
Search Craigslist for a hull in good shape.

-Will

 

[SailorHunter]

I own a boat (Hunter 170) built using the same technology. Luran outer layer, foam, then fiberglass inner layer.

Removing the outer coat? No. This would be WAY more work than fixing the cracks, would expose the core foam to moisture and deterioration, and rob the boat of about 40% of what structural integrity is has at this point.

I would agree that the boat is probably not worth the cost and effort of doing actual "repairs" to. Plexus two-part adhesive is the ONLY proper material and is pretty costly.

My advice? As long as it floats, and as long as you accept and are prepared for the possibility that it may become un-sailable in mid-cruise, then I say apply some band-aids and get your $150 worth. Seal the cracks with a sealant that will bond to plastic. Buy and ALWAYS wear some good life jackets. Sail in protected, populated waters where waving down help and/or paddling to shore is a viable option. If treated as a floating toy, you could have some fun. EDIT - BRING ALONG A FLOATING HAND-HELD VHS RADIO.

It looks to me like this boat will float "for now", maybe even for the rest of the summer. Beyond that, most likely not. Band-aid patching such as I have suggested will NOT help the structure and most likely NOT prevent eventual waterlogging of the interior foam. No matter what, the cracks will get bigger and eventually the boat will become un-sailable. Ditch it before that happens, but go ahead and use it much as you might use an old, decrepit car. Beach it with impunity. Don't worry if it bumps against the dock. If it slips off the trailer, what the heck. This might be a great first boat, where no harm you do to it will illicit more than a good laugh as long as it does not fall on someone's foot.

I would say if it gets you through the summer, money well spent. Go in with no expectations other than that it will fail unexpectedly.

Your experience with this boat will be helpful in determining what your next boat will look like.

Totally agree with this perspective on how to make the most out of this not-so-good situation. I guess it won’t hurt to experiment some possible fixes, to get some limited utility from a hull, which most likely is headed to the landfill. Thanks for the creative ideas and possibilities. Yes, life jacket is a must.

 

[SailorHunter]

http://www.nautline.com/sailboat_plywood_plans.php#N350
The Naut350 looks like a great project to put all that great hardware and rigging to use on.
Or
Search Craigslist for a hull in good shape.

-Will

I have some experience with woodworking using T-88 glue.
I have looked around for plans to build a small sailboat with hull made from wood, using everything that came with the H90 except its hull.The Naut350 looks a good choice. I would have preferred a boat that weighs around 70 to 75 lbs, and no more than 8 feet long. ( The Hunter 90 weighs almost 100 lbs - just the hull ) and is about 10 feet long. I measured the boom of the H90 , it is 6 ft and 2 inches long. Wondering what my options will be to make a sub-75 lb hull. Mostly I will be sailing alone, so the reduced weight will make handling the boat easier when not on water.