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Chainplate Bolts


The weak link in the rigging design, as delivered from the factory, is the choice of bolts that hold the chainplates to the bulkheads and knees. Bruce Rankin published an engineering analysis in the March 1992 Mainsheet and this is reprinted in the Maintenance Manual. I won't repeat the analysis here, but I will repeat the recommendation.

Increase the number of bolts from three to six or increase the size from quarter-inch to five-sixteenths-inch. Either will double the strength of the fastenings.
Add backing plates behind the plywood. We usually use quarter-inch by 1 inch by 6 inch long or so, in aluminum. Stainless would be better, but is impossible to drill in place.

Note also that these bolts should not be threaded down the full length of the bolt. Where the bolt passes through the chainplate, the metal should be full-diameter. This is called a shoulder bolt.

Shoulder and fully-threaded bolts


Offshore Sailing book cover Offshore Sailing by Bill Seifert with Daniel Spurr

We went to a Windjammers lecture to hear Bill Seifert and I was impressed enough to buy the book on the spot. I've heard a lot of people talk about ways to improve a boat, but I've never heard one person suggest so many good ideas that I hadn't considered. Part of the charm is the specificity of the suggestions. Everyone says you should secure your floorboards, hatchboards and batteries. Bill shows good suggestions on how to do so.

The suggestions are very practical for the do-it-yourselfer, too. Many show how to make or adapt inexpensive solutions. Tip #12 on closing the deck blower vents is one that will pay off for me without ever going offshore. I'll implement that one to stop the wintertime storms from finding their way belowdecks.

Besides modifications, the book also includes advice for operating offshore, cooking, boat selection, dealing with bureaucracy, and more.

Bill Seifert has worked at Tartan, TPI, and Alden Yachts. He's a veteran of many Marion-Bermuda races and now runs his own yacht management company. His tips are born of experience--not of book-learning--and it shows. He obviously knows his stuff.



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