Daggerboard/ rudder box

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Joined: Mon Sep 22, 2003 7:28 pm
Location: United Kingdom

Daggerboard/ rudder box

Post by Alistair » Mon Jul 28, 2014 12:40 pm

The hull in the rules is allowed two holes through, one for the rudder and one for the daggerboard. Its quite normal for the rudder and the daggerboard to have a box that makes the bottom of the hull shape. Is this box part of the hull or the rudder/ daggerboard?

Steve Clark
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Joined: Fri Aug 01, 2003 2:26 pm

Re: Daggerboard/ rudder box

Post by Steve Clark » Mon Jul 28, 2014 7:44 pm

Good question!
In the bad old days, the fundamental fixed point was the bottom corner of the stern.
However this point wasn't necessarily always in the same place. This was particularly true of the "fish tail" boats built by Colin Brown and John Ellis which has a hinged rudder box that went clear out the back and included the pointy bit right at the end. If these pieces had not been locked down, it is certain that the boats would not have measured because, among other things, all the station templates would be 30-40mm too far forward and thus would have been too far away from the skin, Similarly beams would all have been wrong.
So in my opinion there is a precedent for considering the rudder box as part of the hull and measuring the hull with that box in place. In the development rule, this only matters for establishing the length of the canoe and the pointedness of the stern.
This does open the can of worms with "movable hull surfaces" on it.
Beatings will continue until morale improves

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Location: United Kingdom

Re: Daggerboard/ rudder box

Post by SteveC » Wed Jul 30, 2014 9:02 am

I was talking about this rule to some one the other week funnily enough.

Two questions were asked;

1. Does this mean that a drain plug in hull is illegal or does this rule only apply for the hull which is underwater in its static state.
2. Can the daggerboard or rudder box fall within the 1m string rule either side of the BMS or is it classified as a (large) concavity.
Steve Clarke (UK)
GBR338 "Money4Nuffin

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