I am just finishing up replacing Alaina's chainplates. The rear one was rusted badly, and the port side ones needed replaced as well. I decided to put external chain plates on her for ease of inspection in the future. They came out okay I think. It was alot of work, however. But it didn't take as long as I thought it would.
I have pictures on www.cruisersforum.com under the profile DaveC.
You could see the rear one needed replaced before I started. However, I decided to replace the shroud chain plates as well since the port-side backing plate was rusted pretty badly (looked like sandwiched cornflakes). I was surprised when I cut out the old glassed in reinforcements that the port-side ones were really bad even though the fiberglass looked perfectly fine from the outside.
Anyways, I'm happy the job is done and the rig is probably stronger for it.
Oh yea, I want to thank Fred Bickum for his insight and advice during this project. He offered me good tips for the chain plate size, hull reinforcement, the backing plate bedding compound, as well as other things from his experience with his previous S/V Fenix.
BTW: The boat still needs cleaned up.... just finished the install this past weekend and need to clean up the excess adhesive, give the hull and topsides a good scrubbing, as well as install the interior back in it. So be nice.
-David Cruickshank
S/V Alaina, 1978 Cape Dory 28
I will try to include pictures below:
Starboard Side.
Port Side.
Stern.
Which one is bad?
The one on left. Rusty water poured out of the otherwise dry glass when I started to cut this out.
All six shroud "chainplates". The three on the left are from the port side, the three others from the starboard side. All looked the same while looking at the glass. There was no obvious indication from the fiberglass covering.
The aft stay chainplate. Talk about a dismasting ready to happen!
The port side backing plate is rusted so bad you can flake it off with your finger. Why Cape Dory used mild steel here is beyond me. Water was getting through the hull-to-deck joint under the exterior wood trim. Incidentally, the glass here is my 5 layers of woven roving. I cut out that top section and reglassed it since water came in during the night and mess it up a little.
The 1/4" thick 304 SS backing plates. Nice and strong. They are bolted against the 5 layers of woven roving glass mat that I applied. I also reinforced the stern since it was fairly thin comparied to the hull in this area.
I bought the bar stock from McMaster-Carr online. A little pricey but whatever. I bought 3 foot bars of 316 SS, 3/8" thick. I cut each 3' bar into 14" plates, and machined them in my garage with an orbital sander, drill press, and grider. I polished them with 400grit sandpaper on the orbital.
I guess if there ever was a time I absolutely had to sheet the jib in very tightly, I could run an extra sheet on the inside of the shrouds. But I can't see that ever being a case.