How big are the holes in your mast step plate?

[jarcher]

Hi All, I am designing a plate to go between my mast step and my mast, to connect blocks to. I have see many pictures posted here of these plates. They tend to be plates with a bunch of holes on each side to attach blocks.

How big are those holes? I am having one of these custom made and I am making a template from cardboard.

Thanks!

[sailingdog]

Depends on how thick the plate is and how you're connecting the blocks to the plate and what kinds of loads you're putting on the blocks. I made the holes on the plates that hold the turning blocks on my boat so that a 1/4" shackle would fit and the blocks are attached to the 1/4" shackles.

[Northeaster]

Have you looked at the Garhauer mast plates? For these low prices, it is hardly worth making your own, if they will fit!

Garhauer Marine Hardware -657583

But, they are all rectangular. I just removed my mast step today, to do the same thing. Since my step, and the raised fiberglass area underneath it are both oval, I think I will have a machine shop make one. I think that a rectangular plate would overhang too much at the corners, and perhaps be a bit weak, as they would not be suppported as well.

Of coures it depends on loads, but for a typical cruising 30'er, anyone know how thick a plate should be done in stainless? What about aluminum, how thick?

[sailingdog]

If your mast step is aluminum, aluminum might work, but stainless steel would be far better, as it is far stronger and more fatigue resistant. However, if your mast foot/step are aluminum, it would be worthwhile to make a galvanic isolation layer to separate the two materials and help prevent corrosion problems.

Originally Posted by Northeaster

Have you looked at the Garhauer mast plates? For these low prices, it is hardly worth making your own, if they will fit!

Garhauer Marine Hardware -657583

But, they are all rectangular. I just removed my mast step today, to do the same thing. Since my step, and the raised fiberglass area underneath it are both oval, I think I will have a machine shop make one. I think that a rectangular plate would overhang too much at the corners, and perhaps be a bit weak, as they would not be suppported as well.

Of coures it depends on loads, but for a typical cruising 30'er, anyone know how thick a plate should be done in stainless? What about aluminum, how thick?