Boatbuilding Blog

November 1, 2009

Side Cleat Reinforcements

Filed under: Building - After Flipping — tomlarkin @ 7:22 am

A lot of distractions these past few weeks have kept me from doing any big projects, so I’ve been attaching hardware and minor jobs like that.

I was concerned that a hard pull on my side cleats (like tying up with a too-short line and being hit with a large wake) might split my gunwale, so I made these bronze plates as reinforcements.  Now, any outward force on the cleat will be transferred down to the hull instead of ripping off the gunwale (I hope).   The material is 1/8 inch silicon bronze plate I bought at Alaskan Copper for this purpose.

I made a cardboard template and traced it onto the bronze plate.  I cut out the parts freehand on my metal-cutting  bandsaw, put them in my bench vise and bent the flanges over on the dotted line with a 5-pound hammer.
image 

I pre-drilled the cleat holes through the gunwale, then clamped the bronze part in place and marked the big hole for the through-hull, then drilled the hole a little oversized.
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Clamped the part in place and marked for the cleat mount holes with the drill bit I used to drill the holes in the wood. 
image 

Then removed the part and drilled the holes in the bronze, starting with a 1/8 inch bit and working up the the finish size.
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Checked the fit.
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I ground down the corners with a 5-inch grinder and 60-grit disk, freehand.  Then sanded with the small dual-action sander, down to 220 grit.  I’m not trying for a really fine finish here – they will tarnish nice and dark soon enough.
image

My main concern is that I have three different metals here – zinc from the galvanized cleat, stainless bolts and nuts, and the bronze plate and through-hull.  I may look for bronze bolts to replace the stainless. At the least, I’ll put a nylon washer between the stainless nut and the bronze plate.  I need to epoxy-seal the bare wood where I drilled the holes before doing the final installation.

Added – I don’t know if this helps, but here is a rough cross-section of the area, and how I think the forces will be transferred away from ripping off that inside 1×2.
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1 Comment »

  1. Nice work. I’m sure that plate will help you sleep more soundly.

    You may want to check out Tef Gel to reduce galvanic reaction. I believe the Navy uses this stuff for Alum + Steel.

    Comment by ChrisS — November 2, 2009 @ 8:52 pm


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