Building a better leeboard

The second major project needed to get 'The Rise' back in good sailing condition is to make a new leeboard to replace the one broken during the 2007 Everglades Challenge. 'The Fall' broke its leeboard while surfing into an inlet during the race, and 'The Rise' broke its leeboard while sailing in catamaran configuration after the race was over.

The Fall's leeboard, before EC 2007

Board construction, from West Systems

The quick failure of the leeboards led me to think the construction methods we used during the first build were inadequate. To speed up the build we made our leeboards with fiberglass covered plywood instead of the recommended laminated hardwood construction. The boards were plenty strong to take the ~60 pounds of force that would be applied to them (we stood on them to find out), so why did they fail? A little internet digging showed the error of our ways; this article from West Systems showed others had made the same mistake. While the plywood is strong enough to take the load, it is much weaker than 'solid wood' in fatigue - the internal layers which are facing the wrong way will slip and roll against each other. Crack propagation along the grain occurs much faster due to this effect. A properly designed hardwood leeboard places all the fibers perpendicular to the bending axis, eliminating this weakness.

Fairing the board using templates, from West Systems

Following recommendations from the previously linked construction tutorial, I'm building a new leeboard from cedar. I found a hardwood supplier near DC called Vienna Hardwoods where I was able to select one big board from which I can rip all the pieces which will make the leeboard blank. After the strips are laminated together I'll fair the board into a NACA 0012 airfoil profile. I'll start a new post once I get the hard part started. For now here is a picture of the Vienna Hardwoods warehouse (so much to choose from) and the very nice Spanish Cedar board I took home with me. It's an 8/4 (roughly 1.875" finished) by 5" by 13' board, which is about enough to make a leeboard and a half. In fact, maybe that's not a bad idea!