CaptDan
Member III
I had the same issue on my boat - minus the chainplate fissure - and successfully scarfed in a new section, which through periodic inspection, has proven sound. Knock on 'wood.'
Fortunately, the rotted part was only the girth of the salon chainplate covering box, so I didn't have to worry about doing the job 'pretty.'
Here are the cliff notes:
First, I had to dismantle the forward part of the bulkhead in the head - removing the shelf above the sink, and the chainplate covering board.
Then, I ground out the old fiberglass tabbing, making note of how it was attached around the hull area so I could duplicate it later.
After cutting a fairly square section out of the rotted bulkhead, I carved a 3/4" piece of marine grade mahogany plywood, shaping it as close to the cut section as I could, then using West Systems thickened with the 'structural grade' powder, fit the piece in.
After that part cured, I sanded and faired the repair (took a full day; that epoxy mixture is TOUGH stuff). Satisfied the area was as fair as I could manage (it wasn't), I filled in the rough parts with West thickened with colloidal silica, then laid another coat over the entire area, allowing it to go slightly beyond the corners - just within the dimension of the covering box.
Next, after fairing the previous work, I laid a couple of layers of biaxial glass over everything, tabbing it up to the hull corners as noted before. Then I did the same in the forward section in the head.
Then I sanded that part down, drilled new holes for the chainplate bolts, and reattached the chainplate with new stainless hardware. Now - the hardest part of the process: re-installing the head shelf and covering board.
Because the rot extended into the aft section of the shelf, it was necessary to cut about an inch off the shelf fiddle in order to get it to fit back in. Plus, the new scarfed section was ever so slightly askew, creating a need to surgically alter the shelf and fiddle. Even then, I had to fill in some gaps using West and that structural powder. (I used the brown variety which helped it blend in with the teak fiddle.)
I followed a suggestion from a wise E35II dude (John Moses) : instead of reattaching the chainplate boxes with screws, I used 3/8" diameter dowling instead. That allows quick disengagement of the box for easy inspection - should any new leaks develop.
Finally I re-caulked/bedded the chainplate where it penetrates the deck. Thankfully, there was no core delamination there. The soundness of the deck is what prevented the mast from going by the board, because I'd been sailing the boat for about a year before I realized my folly.
Certainly replacing the entire bulkhead is the preferred way to go. But - in my opinion, and in some cases - it's not the only way.
Hope this helps. Good luck.
Capt Dan G>E35II "Kunu"
Fortunately, the rotted part was only the girth of the salon chainplate covering box, so I didn't have to worry about doing the job 'pretty.'
Here are the cliff notes:
First, I had to dismantle the forward part of the bulkhead in the head - removing the shelf above the sink, and the chainplate covering board.
Then, I ground out the old fiberglass tabbing, making note of how it was attached around the hull area so I could duplicate it later.
After cutting a fairly square section out of the rotted bulkhead, I carved a 3/4" piece of marine grade mahogany plywood, shaping it as close to the cut section as I could, then using West Systems thickened with the 'structural grade' powder, fit the piece in.
After that part cured, I sanded and faired the repair (took a full day; that epoxy mixture is TOUGH stuff). Satisfied the area was as fair as I could manage (it wasn't), I filled in the rough parts with West thickened with colloidal silica, then laid another coat over the entire area, allowing it to go slightly beyond the corners - just within the dimension of the covering box.
Next, after fairing the previous work, I laid a couple of layers of biaxial glass over everything, tabbing it up to the hull corners as noted before. Then I did the same in the forward section in the head.
Then I sanded that part down, drilled new holes for the chainplate bolts, and reattached the chainplate with new stainless hardware. Now - the hardest part of the process: re-installing the head shelf and covering board.
Because the rot extended into the aft section of the shelf, it was necessary to cut about an inch off the shelf fiddle in order to get it to fit back in. Plus, the new scarfed section was ever so slightly askew, creating a need to surgically alter the shelf and fiddle. Even then, I had to fill in some gaps using West and that structural powder. (I used the brown variety which helped it blend in with the teak fiddle.)
I followed a suggestion from a wise E35II dude (John Moses) : instead of reattaching the chainplate boxes with screws, I used 3/8" diameter dowling instead. That allows quick disengagement of the box for easy inspection - should any new leaks develop.
Finally I re-caulked/bedded the chainplate where it penetrates the deck. Thankfully, there was no core delamination there. The soundness of the deck is what prevented the mast from going by the board, because I'd been sailing the boat for about a year before I realized my folly.
Certainly replacing the entire bulkhead is the preferred way to go. But - in my opinion, and in some cases - it's not the only way.
Hope this helps. Good luck.
Capt Dan G>E35II "Kunu"
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