Browse the Chine bLog Archives

Iteration on the leeboard bracket for AL DEMANY CHIMAN

The leeboard bracket is giving us a tough lesson in the physics of lateral resistance. My first attempts showed flaws in the bracket to clip the board to the single side gunnel. The second attempt, from late summer, is below. I followed the published models and build a bracket that clips to both gunnels.

IMG_0951

IMG_0952

IMG_0953

This system worked well enough at keeping the bracket in place, but I still had the end that meets the leeboard all wrong. I realized two things. First, the bolt was too thin – at 1/4″ it was being bent by the leeboard’s upward, outboard pressure on port tack and upward, inboard pressure on starboard tack. Second, the “face plate” provided too little bearing surface for the board (and the bolt on the outside was too small as well). There wasn’t enough to keep the board clamped in place.

In the Fall, then, I enlarged the “face plate” and made a much bigger knob to clamp in the leeboard itself. The worked much better, but the “face plate” still came apart. In the face of these forces, then, I have now buckled a bit and, how shall we say it… screwed the snot out of it. I am still resisting loads of fiberglass cloth and big metal L joints, but there is more epoxy and bronze than before. I am hoping this will be enough. I find the bracket rather graceful as it is now (scrap white oak FTW!), and don’t want to have to revert to something clunky and ungainly. Physics may overpower, though.

IMG_1115

IMG_1116

Leave a Reply

  

  

  

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>