Centerboard Strap

[Erin]

I need to replace my centerboard strap, and I see someone here has replaced theirs in this project post:
pearson35.com/projects/centerboard_pin.htm
But I do not see who owns that project. Can anyone advise on what materials to replace these straps with? I see it looks like they've used rod and hammered(??) them down into rivets of sorts, which is how the original was done too...
Whoever has tackled replacing these parts before, can you advise on what materials to buy?

My rough measurements, I am currently planning on buying
~1/8" thick bronze, 1" wide, 6" long. (x2) Is this the right thickness?
~1/4" diameter bronze rod, in ~2" increments. (x3)

My questions are... which grade of bronze did you use? Did you use bronze for the rivets, or just straight copper, or...?? And being that I have no experience in metal working... how did you create the rivets?

[Erin]

Well, no one had any help for me on this, but I am quite happy to say that I got it all figured out on my own. I would highly suggest that you check your straps at your next haul out as mine were VERY close to corroding through.

I ended up using silicon bronze alloy 655 (the standard for marine bronze) that I bought from Farmer's Copper and Industrial Supply in Galveston Texas... it was the ONLY place I could find that would sell me small quantities of Silicon Bronze in all the shapes and sizes I needed. They were super helpful.
www.farmerscopper.com/bronze.html

Being paranoid and frustrated with my inability to find what the proper material to use should be, I researched all the bronzes. My findings told me Silicon Bronze was best for underwater, with Aluminum Bronze and Phosphor Bronze being good contenders as well. One must be careful shopping for bronze, as some metals listed as bronze are actually classified as brass due to their high zinc content and resulting de-zincification, and brass will NOT NOT NOT last underwater.

While I was at it, I figured I should just replace all the parts, since they were all showing 40 years worth of wear. I used
- 1" wide 1/8" thick bronze bar/sheet for the straps, ~7" long each. Had them shaped & drilled at local machine shop - though I could have bent them myself with a bench vice, I think.
- 1/4" round rod to make my own rivets to hold the straps onto the centerboard (this probably could have been accomplished more easily with some bronze carriage bolts or something... but making my own rivets was kind of fun)
- 7/8" round rod at 5.33" long for the pin, rounded off on the ends just like the original
- 1-1/4" round rod at 1.75" long for the bushing in the centerboard, which I had hollowed out by the machine shop to the diameter of the original... which I don't remember right off hand.


When I couldn't find a small supply of bronze at first, I had considered replacing it all with stainless steel, but that was not recommended since stainless requires air to form the natural oxide layer that maintains its anti-corrosion properties, and underwater, it will not form the oxide layer. This means that the stainless will pit and corrode much faster underwater than it would on deck. The hardware may still have lasted a good 10 years, but I would have been paranoid about it. I assume the bronze I can trust for another 40.

Cheers!