Boat is breaking up?

We had a hard grounding 2 years ago.  Sections of the stub sump were repaired as well as the for aft stringers back to the engine mount area.  Under the battery box the frame was lifted from the inner skin.  A yard did all the repairs (I had to call them back on stuff they missed).  They undercut the tabbing and re epoxied the tabs back to the hull.  The original impact was at 11-13 kps (yes kilometers) on starboard tack, just a main up and reaching off.  Virtually all the apperant damage was on the starboard side of the boat, i.e. the stub/ keel was pushed to starboard, the port side held fast  and the starboard sid of the stub and framework was pushed up, thus seperating from the inner skin.  This spring, looking in the stup/sump I find a break in the aft port side of the sump running from the top of the tab 1-2" down and the forward frame (under mast compression post) cracking arround  and down from the limber holes and wire passes (this area had been repaired also) .    Does the yard need to attend to this or is this seperate, we haven't grounded since. 

Racing starts in 1 month.

WarBird 0169

The repair 2 years ago was wholy inadequate.  I should have known when I had obvious defiencies right out of the yard that were later addressed.  Now the yard says they can look at the boat in July.  HaHa fu---ng HaHa.  Repaired tabs are seperating, the plates (Bronze) under the keel bolts are in pieces and we didn't know that until we pulled the keel bolts this spring.  Pulling the keel bolts (center) show cracks in the frame that seperates the sump.  Some sump tabbing is seperating from the inner skin.  We currently have nuts and plates out, new plate made in 1/4" stainless plate,  and the sump and tabbing ground down to glass/kev.   We will lay in some basalt cloth and west epoxy tommorrow, tying the sump insert to the inner skin outboard of the keelsump tabbing.  What else am I missing.

Murph,

Thanks , we'll keep that in mind.  We ended up using 9 oz tape, cutting hole in way of the bolts and lminating from the sump up to about 4 inchs of inner skin.  Fillets on the transitions.  As we were doing the job my sidekick said he saw stuff we might have to do next year.  Now boat is in the water and we'll keep a close eye on it.  Thanks to all for the input, insight and suggestions

 

WarBird

I had a similar grounding and the impact flexed the bottom enough to debond and break aft frames from hull! There is NO sense in re bonding the bottom flange of the stringer or even laying up glass over them. The leverage of the flange will quickly cause failure.
Grind off all of the tab (by the way, a good grinder makes quick but messy work of removing material - it's not a big job!). Grind gel coat off of molded frame in repair area - get down to laminate. Sand hull skin after flange is ground off. (you and create a plastic tent around the repair area and tape yourself in while doing this grinding. Remove ALL cushions and bags!)
I used epoxy for my repair. Better adhesion. I used many layers of lighter bidirectional fabric rather than heavy material as it has to bend around frame with substantial geometry. Pre cut all material to approximate size before starting. use enough layers to replicate original flange thickness but layers can drop out as they go over sound existing frame. It's good to taper number of plies towards outboard stringers if they are still intact. Use peel ply on all surfaces to make a neat job as this area is visible under floorboards.
I spent a lot of time filling and fairing the frame then painted it.
    I found that the Ring Frame under my mast compression post was failing! the aft face was buckled in a perfect shear "X" pattern. Cracks were starting from hole drilled for wires.
I took out the post (mast down) and sawzalled out fwd and aft faces of ring framewhere failing (about a 20" section of middle). The block under the mast was wet and filler under it had crumbled. Shear web faces of ring frame were sticky and soft laminate and it was just glass mat - no woven materials there. With just the frame top surface in that area I could clean up the hull skin really well and then I laminated several layers of material on hull inner skin in that area. ON top of that I fitted a 4x4" wood block, well "pooped" in a bed of Cab-o-sil thickened epoxy and fitted to underside of ring frame top.
I then made a light cardboard insert to fit in the cut away areas of the ring frame fore and aft faces on either side of the mast block, to act as a mold to lay up against. The mast block faces were flush with the inside of the new frame faces so cardboard "molds" attached to left and right of the block. These were bonded in with bondo. I had tapered all the edges of the frame cut out with the grinder, back about 2".
I laid up new material with epoxy from frame flange up the web faces abd across the top, down the other face and out to the flange. I cut +, - 45 degree fabric for most of the web faces and used some unidirectional along the top and bidirectional along the flange and over the whole frame. I'd say that frame side were built up about 1/8" and flanges were 1/4" or more. Skins were laid up over cardboard mold and against fore and aft face of mast post support block.
I peel plied all this and also did taper laminate as I got near undamaged frame sections. I spent a lot of time to make the frame smooth and blend the repair into the sound frame either side of the repair. I painted it and the repir is almost indestiguishable from original except that repaired flanges are tapered to the hull instead of having trimmed edges, bonded on.
There is no doubt that the new ring frame is far stronger than original construction. Now I was able to maintain rig tension again!