Hull Side Delamination Repair

So I have a large soft spot developing on the outboard side of my port hull between the forward crossbar and the shroud anchor point, and I'm trying to decide what to do about it.

Does anyone have any experience with soft spot repairs on the side of the hull?

I had planned on the typical drill & fill repair with West Systems 105 epoxy, so I taped off the section and began pressing on the soft spot (maybe 18" diameter) to find the boundaries so I could identify where to drill my breather holes. *CRUNCH* okay, that's soft. pressing around it... *CRUNCH CRUNCH CRUNCH*... well damn. I now have about a 3 foot long section that is soft, from just below the hull lip to just above the "keel", pretty much the full area that has foam the foam sandwich construction. I stopped pressing after a little while... I'm worried that I'm making matters worse, and I should stop pressing on it and just fill the area that I know is soft. It seems like once one area is soft, pressing around the edges just causes the spot to expand because you're over-stressing that spot and it no longer has well bonded foam/fiberglass next to it to help share the load.

I don't mind a little extra weight from soft spot repairs, my hulls are '78, and the last soft spot repair I did in the deck added around 1 lb of epoxy. If this ends up being 5-10 lbs, that's not awful. My concern is, if my hulls are crunching under about 10-15 lbs of external pressure, is it pretty much delaminated already anyway? Would I be better off continuing on to find the areas that are still well bonded and then fill the large soft spot that I've created? Or do I just stop pressing and drill my breather holes around the existing spot that's already soft, and leave the rest of it alone? Or fill one area, then repeat the process forward of the now filled soft spot and see if it crunches/drill & fill as necessary?

Structurally speaking, if you're able to rebond the fiberglass & foam, the hull would be as strong as it ever was and should be in perfectly good condition to sail. I'm thinking I can add temporary supports inside between the inboard & outboard hulls to keep the inner layer from sagging under the added weight of the epoxy until it cures, and try to "squeeze" the inner and outer layers together to minimize the amount of epoxy in the hull. But if the whole thing is separated, it'll be too difficult/expensive to try to drill & fill the whole thing and maintain the proper shape & hull thickness.

Are there any other methods of repairing soft spots/delam worth exploring? I know I saw srm installing longitudinal "ribs" on his 18, but I believe that was on a hull that was still in good condition, not going soft.

Any thoughts or suggestions?

_________________
Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

The injection process is the same regardless of whether it is the top or side of the hull. But I would take the boat apart so you can lay the hull on its side to prevent the resin from just running down out of the bottom holes. I would stop pressing hard on hull until you fix the damaged area because as you noticed, continuing to press on the soft spot is just going to cause it to grow. The problem with using the injection method is if there is porosity on the in er glass ply, the resin may seep out of the laminate.

You could put stringers inside the hull. That will stiffen it up which should help prevent soft spots in that area in the future. But the hull needs to be intact first. The stringer will not fix an existing soft spot, it will just make the existing hull more rigid. Putting the stringers in is also a lot of work and will add more weight. You’ll need to cut access holes in the hull and do a lot of work in a tight space. But the hulls will be very stiff after the stringers are installed. At 200lbs, I could walk on the side of the hull and feel no flex where the stringers were placed.

sm

That was my plan as well, to lay the hull on it's side for repair. I've now got such a large soft spot though, I think I need to support the inner layer to keep it from separating further from the outer layer under the weight of the injected epoxy, so I'm thinking the best approach would be to put temporary supports internal to the hull to help keep its shape while injecting the epoxy. I'm also entertaining the idea of using some kind of inflatable bladder inside the hull to keep its shape while I inject the epoxy. I agree that it is unwise to continue to press on the hull to find the extent of the soft spot. I think the best approach is to fill the existing soft area, then test the areas forward & aft to see if they are soft once this area is repaired. Looking on the inside of the hull, I haven't seen any evidence of porosity, so I'm not too concerned about that.

The soft spot as it stands covers the area outlined in permanent marker here: https://photos.app.goo.gl/dxyShUrxhtDaTWxM6

I am looking into replacement hulls in the meantime, but I'm really reticent to give up on these hulls entirely after the considerable time I've put into making them look like new (or as close as I could get them).

Stringers seem much more invasive of a repair than I'm interested in pursuing, especially now that the integrity of the entire hull is in question.

_________________
Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

I had this problem.. The solution was to leave it in the hands of an expert

Holes were cut in the solid glass along the bottom of each hull, old foam cut out (removed in pieces), new foam glued and fibreglassed, holes filled, faired and flow coated.

It was major surgery!

Wish I still had the photos, will see if I can get them

_________________
H18 Newbie, Too heavy for the 14

That's what I've been told as well... the only real repair is to cut out the inner layer of fiberglass and re-glass the entire area. Seeing as it extends forward of the front crossbar and back alongside the dagger well, I'm not sure it could be done without cutting open the deck for better access. Unfortunately, I think the hull is done. I've picked up an extra set of old hulls and I'm getting those back in sailing shape. I'm reticent to scrap the old hulls, but I just don't think there's any practical way to fix the port hull.

_________________
Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238