Stress cracks below the waterline

[Maxx Mayhem]

As I've been cleaning up this boat, I have discovered pervasive stress cracks on the bottom. Now I have been aware that the top of the doghouse is totally covered with cracks, as is the area around the toe rail, those areas are bad enough I plan to grind off all the jel coat , add a few layers of new glass, fair paint and nonskid, however, I had at first hoped to get away with the dremel tool - epoxy filler method on the bottom. With the number of cracks I have discovered, I wonder if that even makes sense, Or should I do the same thing on the bottom as the top, grind off all the jel coat, add some glass and refinish from there. Best I can tell, they are like this everywhere. Thoughts? Also, wondering if anybody here has ever turned a boat of this size (22ft) over to repair the bottom...Thanks

 

[Justin_NSA]

Is it stress or did the boat strike something? My guess it would be harder to fix stress cracks, implying movement, versus an isolated strike. Did the trailer cause it?

 

[Maxx Mayhem]

No trailer.. My guess is that this boat had been in the water until I picked it up. These cracks seem to be everywhere. It spent most of its time in Back River, Md, where it often rested on the bottom due to its very low water level, which goes down even more with the right winds. It had sunk at one point, however, I do believe the cause of that has now been fixed. My thinking is similar to that of yours, that even if I fill all of the cracks, new one will continue to appear, that's why I'd consider redoing the whole bottom, preferably with s-glass and flexible epoxy, followed by barrier coat under the bottom paint...

 

[rgranger]

Those look superficial to me. You don't want water intrusion but I certainly would not grind out the gel coat. Instead I would concentrate on creating a very clean surface and then put on multiple layers of barrier coat epoxy paint followed by a hard enamel rated for below the waterline (to protect the epoxy from UV damage) and then (if you are going to keep it in the water) end with an anti-fouling paint. If you are going to mostly trailer and launch, I would skip the anti-fouling paint and stop at the enamel.

I have flipped (as in bought cheap, fixed and sold) seven older boats so I have actually done a lot of this sort of work. I would not recommend turning the boat over unless you first remove the keel and even then I would be a little nervous about it.. But I don't think you need to do that if you are simply going to barrier coat the bottom.

 

[Maxx Mayhem]

It certainly would be easier. My concern is more cracks opening, as a I was thinking of using coppercoat. It costs more initially, but then you are good for 12 years.I think I'll try sanding an area and watching it for a couple of months, and if all looks well, I'll proceed the way you recommend.

 

[rgranger]

It looks rather clean now. I'd pressure wash and paint while it is out of the water. If you are trying to go on the cheap, you can get barrier coat epoxy paint made for swimming pools at James T. Davis or Sherwin Williams etc. I have a good friend who works at James T. Davis and he turned me onto that trick. He told me the marine stuff just comes in a different label and costs more. I've had really good results with that paint and it was about 30% less than the marine rated paint. Roll two or four coats of that on the bottom of your boat, then get some Rustoleum bottom paint and call it done (unless you want anti-fouling paint also).

 

[Maxx Mayhem]

Not really trying to do it with the cheapest material, just want the repair to last. I'm planning on copper coat for the anti fouling, which costs a bit more, but should be good for 12 years before major maintenance. But if the substrate cracks, back to square one.

 

[shemandr]

It looks like the cracks are in gelcoat. Usually that means the laminate deformed underneath the gel coat. Deformed doesn't mean structurally failed. Could be short term impact or longer stress on the hull. I don't think I'd freak out about this. If there is no water intrusion, I might do the barrier coat but maybe not if dry sailed. Bottom paint if not dry sailed. There is practically no repair of a boat that is a 12 year fix. Don't chase your tail about this. Take it out sailing.

 

[Sanfelice]

Since you also have the same cracking on the deck and cabin top ,I would guess poor formulation of the epoxy at the time of construction. I have only see one other boat with that many cracks, a Cape Dory 33. I think a good bottom prep and a barrier coat would solve the issue below the water line. Perhaps doing a barrier coat on the topsides might even be an option. Eventually, you probably have to weigh the cost versus benefit as to how far you will go in restoring the boat. You could most likely sail that boat for years without doing anything but bottom paint.

 

[Maxx Mayhem]

I'm thinking that if I can get a decent barrier coat and bottom paint, that will be cool. As to the top, a major redo should not be to complicated, I have all the tools etc. And it is a small area.

 

[Dennis Kitchen]

I had even more of the same on my H25 rebuild. I dremeled-out the cracks and filled with epoxy mixed with fumed silica and micro balloons. Lots of sanding afterward. I will epoxy barrier coat and then epoxy prime before bottom painting.

I carefully ground out or gouged out several of the cracks and looked with strong light and magnification to determine if it was just gel coat or into the laminate. I even did a dye penetrate check on several. I never found any that went past the gel coat except a couple times into the first chopped strand mat. The structural lay ups were never cracked.

 

[svchickadee]

A good waterproof barrier coat is coal tar epoxy.

 

[Crazy Dave Condon]

I came aboard as a Hunter dealer when the old style 22 was being phased out for the new 23 wing keel. I had the option of purchasing one of the first 10 23's with the swing keel winglets but opted to wait for the fixed wing keel version seen in the brochures.
I cannot say how many hulls stripped by me and repainted but a lot is based on experience. We are dealing with at least a 34 year boat or older so no one knows what it has been thru.

Most of the cracks in the hull generally are only in the gel coat itself and not in the fiberglass hull. With that said, I was not a fan of stripping down to bare fiberglass in the gel coat on a hull if there were no leaks. Many of the yards preferred not doing that. Instead, blisters were opened up unless severe requiring a soda blast, sand blast or by the old way of hand sander sometimes requiring removal of defective gel coat in the 90's causing pin style blisters over the hull. Then the hull should be allowed to dry out because any sealing with barrier coat, will cause more blisters if painting over a wet hull. Yes it takes time for a hull to dry out. Once done, final prep for blister repair and then smoothing of the hull with sandpaper. We applied 4-6 coats of Interlux 2000 I think barrier coat on the hull. I suggested 5-6 coats but some customers to save a buck reduced that. In my contract, I would warrnanty my repair work but with 5-6 coats applied, Then of course prep for antifouling and suggested talking with the locals what worked best for the specific area for example Trinidad by Petit for coastal North Carolina.

Rob made a good point about not applying anti fouling to trailerable sailboats that do not stay in the water but on the trailer. As for the bottom we will disagree about applying anything else other than the barrier coats and I would stick with those tried and proven which I stuck with 2000/2001/2000E or what ever it is now. As for UV rays on the hull, never really a problem

I had a fellow who came in to paint the decks and he had done this for a living. If spider cracks, leave them alone other than cleaning the deck, paint by spraying {least desired due to extra work to cover everything up to include other boats around) and tip brushing. Very true in non skid areas. Like everything, maintenance to the boat is required as many never do and years later, paint is fading. I will not comment any further as I had this fellow do the deck painting. .