Attached are files and information Russ Atkinson sent on chainplates he fabricated. These are also referenced on the J/30 Files and Drawing page
Here's a PDF of the drawing for the oversized chainplates. Please note my comments below:
I had these made at a local fab shop. The plates were cut complete, including all the holes using a waterjet cutting machine. Material used is 1/4" x 304 stainless
To simplify the drawings and the work required to install these, the overall width of 6.3" should be reduced by .375" and all the material should be removed from the outboard side.
I did the initial layout for these chainplates on the starboard side of wildcat. I didn't have the sense to compare to the port side. After making the drawings and the parts, I found out that the port backing plate interferes with the cabinet in the head (starboard side backing plate is in the hanging locker and there is no interference). Also, the port side cabin light was in the way of the port chain plate. I had to move the light.
My company sells complex CNC metal cutting machines so, for me, there was no problem in bringing the port chainplate and backing plate to my business and having my engineers mill off 3/8" from the edge. For me that was a lot easier than modifying the cabinet face in the head.
Also, I used my old chainplate as a template for where the center 6 holes would go. I cannot guarantee that someone else's chainplates are made identical to my originals. That is important to check making these. To install these I merely removed the old ones, mounted the new ones using the 6 original holes and then drilled the additional new holes through the chianplate and backing plate. (Tip - drill holes half way from both sides).
