cracks on the C Shark advice needed please

D

droz

New member
After 10 great days of fishing the Seward Silver Salmon Derby we came home with some issues :( Our problems started in 2008 with a crack at the back of the cabin and inside on the cabin floor where the tube for the water tank came out and a small amount of water getting into the back of the cabin. We had both of these fixed but still had a small amount of water getting in, mostly when it rained. There was also a crack inside the cabin where the small step is into the V berth. After one season the V berth step cracked again. Took it back to the shop last year for repair in the hull after hitting a log. Had a nice chunk out of the fiberglass on both sides just about where the bottom paint ends at the V berth. The shop investigated the water leak and thought it was coming from the drain plug at the back of the cabin so he sealed it up. The shop recommended not fixing the inside crack into the V Berth as he thought it would just crack again. First couple of trips out there was just a tiny bit of water in the cabin until our big trip last week we now have water coming from the inside crack into the V berth on both sides. When we pulled the boat out found damage in the same place where we hit the log last year. I think this means I have water in the hull! uploading pics now any advice would be greatly appreciated!
 
Reading your post but not actually getting a look at the boat, quite a few ideas come to mind. Yes, it's possible you have critical hull damage, but I could also easily see a few scenarios where you have coincidences and the cause(s) are not so severe. (I might change my mind were I to see the boat and/or photos.)

I have a 2002, so we probably have a similar set up for the drain plug amidships just below the cabin door. I removed/reinstalled mine, and I could easily see how it could leak - reason is that the hole is right at the bottom (as it should be to function), but there really are no fittings that work on a limber hole. Thus they used a regular drain fitting, but cut it flat on the bottom side, which means there is really no fastener or flange to seal along the bottom. I went back in with a new plug and slightly better installation, but my ultimate plan would be to either relocated the bilge sump to that area (in which case the drain hole would be superseded), or glass that hole over. At any rate, while it's possible to get it to seal, it would be entirely unsurprising if it were not sealed.

On the porta pottie platform: From what I can see, that is a sort of liner/molding which might not have much support, depending on how/if foam was installed under it. Mine was made with a 6" deck plate (round) and under it is completely filled with foam, which provides good support. But if it were not, I can see that would be prone to cracking, especially if a heavier person stood on it.

Then there are the known leak-prone areas: The anchor locker drain and the brass bow strip. Either of these can leak right from the get-go, depending (it seems) on luck of the draw from the build process. That water would end up under the V-berth liner molding, so could easily come out aft under the porta potti area.

I've also seen where a number of 22's have stress cracks where the main cabin sole steps up into the V-berth (on the sides). That may be more or less cosmetic in nature (not purely cosmetic but not dangerously structural, if that makes sense) (I say, only having seen that in photos).

So I could see where those things could combine to make it seem that the hull itself were cracking/leaking.

On the the other hand, these are cored hulls (from just ahead of the main cabin aft), and it's possible to have damage that would be considered structural if the core gets wet and weakens the boat. This could come from hull damage that penetrated the skin;or from fasteners or fittings that penetrate the skin (fuel tank cleats, bilge pump screws in after sump, any through hull that may have been added).

If/when you can add photos that would help a lot.

Sunbeam
 
I have examined the photos you posted. What you show there is the tabbing of the "V" berth molding (includes the floor just forward of the helm and the porti potty area, plus the platform for the V berth. This is not a complete bulkhead, but rather a half bulkhead, including the aft part of the V berth. The bulkhead in the forward part of the C Dory 22 is free floating. It is bolted to the afore mentioned molding--(V Berth) at the bottom and glassed into the deck molding above. It is not tabbed into the hull at all.

Any water coming from the area of the cracking is most likely coming from under the V berth. As Sunbeam mentioned this is either due to improper screw fastening in the brass strip on the bow, or from the anchor locker.

There is a remote possibility that this is coming from the damage you had to the hull. It appears that the boat has been driven hard (pounded) or that this break in the tabbing is a result of the collision with debris. The core of the hull does not normally start until aft of this half bulkhead--or the under the V berth is solid glass.

The water intrusion aft is from the only full bulkhead in the boat--and that should be tabbed into the hull (floor on both sides--but your boat has the glassed in floor in the aft--which complicates things considerably, since you cannot access this area easily. The entire aft cabin bulkhead needs to be securely tabbed into the hull along the bottom and sides of the hull.

Questions:
Where is your bilge pump? Are there any signs of cracking of the tabbing aft (this is layers of mat and cloth or roving which go between the aft bulkhead and the hull)? Do you have the molded interior?--my guess is not. Have you redone the screws on the brass strip? Have you redone the anchor locker so that there is no possibility of leaking under the V berth? Exactly where was the damage on the outside of the hull--was it just in front of the helm? Was there any evidence of core material exposed when the damage was done? Any photos of the damaged area outside?--include the entire side of the boat, so we can see exactly where the damage stopped.

Comments:
The repair should include grinding off the old tabbing, removing all of the old tabbing in the front. Then the tabbing should be replaced with two concentric layers of 1708 cloth with epoxy (not poly ester) The layer next to the hull, should be wider than the next layer by an inch--ie 6" total for the first layer, then 5" for the second layer. 4 layers of 6 oz cloth might be used if you cannot get any the 1708 cloth, but the 1708 will be stronger, and with some evidence of this weakness, I would go that way.

The aft bulkhead needs to be done the same way. You will have to remove the water tank, but not the furniture. (wood work of the interior.).

I agree with Sunbeam for the most part. The "floor" of the "V" berth area should be sufficient strength to stand on its own-and any foam is both dampening of sound and of little structural issue.

Unless the damage to the hull extended aft of the "V" berth half bulkhead, it is unlikely that the core is compromised. However, I would be concerned that the repair was not properly done that you are having breakdown in this area. I cannot emphasize enough that any structural repairs need to be done with epoxy. Many repair folks are used to working with polyester and not epoxy. The polyester is significantly weaker in secondary bonding. The polyester layup of the hull is all primary bonding (all done at once--and a good chemical bond). The other concern here is that all of the damaged glass on the bottom was not removed, and that perhaps the glass was not sufficiently dried before the repair on the bottom was done. After a collision with a log, the fracturing can go back some distance into the glass beyond the obvious damage.
 
I'd call Joel Morse at Ashbreez Boatworks in Anchorage and ask him to take a look at it. He did some work on a previous C Dory that we owned, and I was extremely happy with the results. He's very good at dealing with structural issues, and he knows his way around a C Dory. And by the way, nice work on the silvers! It's been a good year for silvers over there.
 
Joel is on my list to call - he took care of the log damage from last year. It's nice to have a new fiberglass place up here finally! I just like to have a good understanding of what I'm dealing with before I take it in.
 
OK, I have seen the new photos you posted. The impact damage should be in areas which are full glass--no core. Was there more damage deeper in the hull, or was it just near the chines where you show the damage? I would stand by my suggesting to grind out this area, and repair with epoxy and glass cloth, be sure to feather out where the new glass goes on a 12/1 ratio--be sure that the glass is plenty strong and thick in this area.

The aft area, again--is an area where there needs to have the tabbing redone.

What I would do:
1, pull the brass strip, and drill out the screw holes, pot with epoxy, and drill new pilot holes, being sure that you do not go thru the laminate. clean up the area that the brass strip is bedded in, and then re-install the brass strip with 5200.

2. Put colored water (food color) into the anchor locker and see if any of this colored water comes out from under the bunk--floor area. If it does, then fill this area and the current drain hole, redrill the drain hole after reglassing the bottom of the anchor locker

3. Put new tabbing as above on the forward V berth to hull, be sure and spread out the tabbing on at least 2 to 3" on each side of the area which is cracked--old tabbing must be removed first--use epoxy for bonding, and adequate glass build up--taper the tabbing.

4. Redo the tabbing aft--you will have to work on the inside of the boat, assuming that the floor in the cockpit is solid and glassed in. If it is like the 2006 boats, with the removable floor, then tab on both sides of the bulkhead--as in the forward repair.

5. grind out the old repair: taper in the new glass at least 6/1 taper, better @ 12/1 taper. Build up adequate glass. Use epoxy, no fairing except at the very end--it will probably be best to over build the glass, and then sand it fair, than skimp on the glass and use fairing compound after.

Good luck on the repairs.
 
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