Chainplate drilling

[Douglas]

Hi Ben, I too replaced my chainplates and had to drill the staggered holes in the wider double shroud plate.

My asumption for the staggered holes was to "Spread The Load", over a wider area, as that single plate was used for 2 shrouds.

My pre-bent plates were cast by Pete of P T Foundry, but they were supplied holeless.

I ended up drilling only the top bolt hole first, then squareing up the hole with my Bosch Jig saw, because I was using carriage bolts with the square shoulder, under the head.

I then dry-bolted the new chainplate in place, and marked the hole pattern from inside the boat.

Bruce Bingham wrote a book titled Ferro Cement Boat Construction, or something like that,,,, He describes how to determine the shoulder width needed around the chainplate toggle pin hole, so before you drill the pin holes, you might look at that book.

On my boat a BCC, with mast supplied by Forespar, I found the tang linkplates at the mast to shroud attachment through bolts, to NOT have enough shoulder to hole setback,,,,, something like a 7/16" shoulder, when Bingham's book recommends a 5/8" shoulder .

I also found that the cone-type step drill bits were excellent in drilling a very nice "round" pin hole in the new plates, after first drilling a 1/8" pilot hole.

Would you be able to disclose the price that you paid for that Silicon Bronze plate ?

Out here in SE Asea, I recently had my Silicon Brnz plate supply stolen, so I am trying to establish the value of the loss, drats !