Hi Bacho,
I've been "worrying" your problem in my idle moments for the last several days in my free moments ....
So I have come up w/ some more suggestions ....
I think you should contact the following people ....
1)
[email protected] ph# (831) 475-7245 He is a "Hobie" Dealer/"Multihull" Supporter located in the San Diego Calif .... he has developed many good videos on fixing different types of "problems" w/fiberglass hulls .... he posts here on the "Hobie Forum" and "Catsailor Forum" also ... I would contact him and send him "pic's" .... and ask his advice .... he has a great reputation in the "Multihull" community ......
2) Contact Mr Jake Kohl of Greenville S.C. (is that near you???) ..... you can reach him at
[email protected] .... he posts on the "Catsailer" Forum .... he is very knowledgible .... he has alot of experience in fixing fiberglass boats .... he even owned a H18 at one point I believe ..... he too is well known and respected in the "Multihull" community ..... maybe you can get him to stop by and look at your problem .....
Now I've come up w/ a slightly different plan .... have you ever carvered a "pumpkin" ?????
Your problem is one of "access" ... so you can fix the hulls .... so first you need to completely strip the hulls .... if you look closely at the H18 hull construction, your will notice that the very bottom of the H18 hull is "solid" fiberglass that extends up both sides, then it turns to foam core construction .... measure that distance .... now w/ the hulls upside down you are going to cut several openings .... if you mark out a opening that stays in the "solid" fiberglass constructed area and set your jigsaw to a 15* bevel .... you can easily cut out several openings along the bottom/keel .... now my experence has been it's just as easy to fix a large hole/cut-out as a small one but a large one is easier to work through ..... by this doing this it will allow you "easy" access to the inside of your hulls ..... sand/prep the inside surfaces ... you then will be able to reinforce the deck/hull seam area ... reinforce the cradles ... install layers of cloth and resin to fix the crack .... now you will need to install a "lip" so you can re-install the pieces you cut-out .... West Systems sells a 45* bias "heavy cloth 6" wide "tape" you can sandwich between the hull and strips of "marine" plywood (4mm?) that you epoxy in place .... you may wish to fully enclose the plywood in some additional layers of regular 6" wide fiberglas tape .... re-install the pieces you cut-out and saved, fill and fair will thickened epoxy ... and re-skin as I discribed in one of my earlier posts ....
Now the cause of the cracks is the "toeing in" of the hulls under load ... this is famous in the "red-line/red-foam hulls due to their lighter construction ... and as the hulls get weaker then they start to flex vertically too, till one day .... rrrrriiiiippppp ... the bow tears away (you remember I mentioned earlier about my 84' hulls and the 86' hulls .... the 84's ===> red-foam ===> RRrriiiipppp ===> Hobie had to replace them w/ a set of 86/87 hulls under warranty) ... so a suggestion .... while you have access .... install a horizontal "sub-deck" ... you can use "Nomex" foam core or marine plywood (the early P19's had a problem w/ "toe-in" and thats how they solved the problem in later production runs and the Mystere 6.0's was made w/ them and they are super stiff hulls) ... so I would install a "sub-deck" from just behind the front crossbar (maybe from the daggerboard trunk) ... forward for 2-3' in front of the front crossbar as this is were the most compression loading is .... this will "tie" the two sides of the hull together so they stay "in column" .... this flexing/bulging may have caused the long "bulge" in your hull ....
(to check the "early" P19's you run the palm of your hand over the in-board side of the hulls just in front of the front crossbar feeling for ripples/waves ... and sometimes you see actual vertical cracks ... to fix properly, you have to "pop" off the foredeck and install a "sub-deck")
Now since your brother and you have experience w/ West Epoxy ... you know what "amine blush" is correct??? And understand how that effects your procedures/timing for epoxying ....
Bounce thse ideas/concerns off of Jeremy and Jake .... and let me know what they advise .....
Again this is not too technical work (at least in my mind ...), but will take a serious amount of time ( I actually enjoy these kind of "projests" ....)