Aluminum Bulkheads

[kuriti]

Well, i got my aluminum bulkheads back from the welder today. i bought the metal online and cut it with the grinder. the chainplates come in at an angle, so i kept that angle to the cross piece. thus, they are not 90 degrees, but the long piece will be square with the chainplate. total cost @ $70, and no more bulkhead worries...ever.

I am happy about these, but that is not really why i am posting. it is the bow chock bolts again, but i didn't think anyone would check my last post if i updated it. I know i could chisel out the fiberglass to reach the nut, but it seems much easier to just drill out/grind off the chock and replace the chocks slightly more aft and center with a backing plate. From looking at the fiberglass, it looks like i would be cutting into roving, not just mat, which is structural. then, i would have to re-fiberglass the cut. if i grind it off, i can just re-epoxy the hole and bobs your uncle.

thoughts? i am only asking because i make it a policy not use the grinder without deep thought

Here is a pic of my bulkheads:

IMAG0011.jpg (36.05KiB)Viewed 27878 times

[bluepearl]

You could just move the chocks, but I'm not sure thats really necessary. In my experience, cutting through the glass to expose the bolts and nuts on the SJ is pretty trivial. You could probably cut through the glass with a butter knife and expose the nut sufficiently to tighten it back up. I'm pretty sure its not structural, at least I hope its not. Moving it sounds like a lot of extra work.

[kuriti]

I ground them off. You must have some bad ass butter in your house or our lay up was much different. Once the chock was gone, I hammered and chiseled the bolts out. Would rather have easy access in the future anyway. Thanks for the reply though.

[bluepearl]

Your boat must have been built on a Tuesday, so the chock position and deck layup is probably totally different than mine. Clark Boats aren't known for consistancy. I'm from Montana so all of our butter is frozen solid this time of year, thats why we need tuff knives

[Black Jack]

Did you try unscrewing the chocks. I removed mine as the spin sheet hung up on then when I least wanted it too. I remembered most of them just unscrewed as the nut was held in place by the glass. It was a couple years a ago, but I know I did not need any power tools to remove them.
But given the consistency of the build I am sure I got lucky. Oh and do not be afraid of the grinder. I had to repair a hole in the side port side of Black Jack this past weekend after a t bone at the weather mark at the New Years day regatta. Grinder made short work of damaged fiberglass. All back in one piece now except some cosmetic work. Just waiting on some warmer weather.

Dan Bornarth
Black Jack #2403
Fleet 8

[kuriti]

I did try to unscrew. Definetly worth a try and preferable to cutting them off, but turns out the nut and bolt were epoxied together. I used the chock with the grinder almost clean through then used a big flat head to pop it apart. Then cut the bolt head off and hammered from atop while chiselling below. One bolt had about 1/4 in of fiberglass around it.

[Diarmuid]

One advantage to excavating Clark's epoxied-over nuts wherever possible: you can add proper backing plates. I mean, the stern cleats, bow cleat, and pulpit stanchions on our Mk1 were backed up with 1/2" diameter washers, no larger than the nut itself! Even in the solid FG areas, where there is no balsa core to leak, that's questionable. Strength is poor and water still gets under the fitting & starts prying the laminates apart. Also, SS corrodes in the absence of oxygen; it really shouldn't be glassed in. Our stern cleat screws, when removed, were badly galled.

I'm okay with the skene chocks; they've worked well for anchoring out & mooring, even in nasty conditions. The bow cleat could be one size larger, but we still fit twin 3/4" mooring pendants under it. The stern cleats were a joke -- wouldn't take any decent-sized line, two machine screws & no backing plate. The gelcoat was stress-cracked around them. We replaced those with some 6" Herrschoffs w/ mongo backing plates.

BTW, we moved those OEM stern cleats to the side decks, just ahead of the bulkhead. It's been really nice, having a midships cleat for docking, tying the dinghy off, and cleating a preventer. They're low-profile enuf, they don't snag lines as often as you'd think.