Maximum draft

[Richard98 1]

When I had my Marblehead I was aware that, despite having a very long fin, newer boats were even longer. Therefore I could not expect to compete with them, except in light winds. My fin was already too deep for our main sailing venue and these considerations led to me selling the boat. 

What is the maximum draft allowed ?  Measurement rule C5.2 only refers to a gauge with no indication as to what size it should be.  Just curious really.

[John949 0]

The rules give the dimensions of the gauage.  The max length of the fin (to the bottom of the bulb is approx 660 mm from hull surface.

[Eric Finley 0]

Richard

Look at Marblehead Class Rules section J.1 (In the 2018 edition) and there is a drawing of the gauge. The Max length is less than 660mm but not by much.

Eric

[Richard98 1]

Thanks John and Eric. I am looking at CR2020, which I assume must be more up to date than the 2018 issue. So the max fin length , with ballast attached, is 660mm then the hull draft is added giving a draught of >700mm. That sort of equates to the 10R for the purposes of dual rating and is what I will aim for. When I built Paradoxes the draught was a mere 600mm.

Thinking ahead to next project.

Richard

[John949 0]

APPROXIMATELY 660, you have to make the gauge if you want to be sure.  My 10R and M fins are about the same length.  I thought about making them interchangeable as the 10R is 400g heavier but don't want to start an arms race for club level racing.  It may work for you but most people would suggest that a dual rated boat would suffer against a real 10R when the wind gets up.  The overhangs increase the waterline length as the boat heels / starts making a significant bow wave and the forward one helps with nosediving allowing a bigger rig to be carried in a given wind strength.

[Richard98 1]

Agree with you there John. I did put a few M's together with a specific request to make them dual rated. I tried a 10R rig on the M and was impressed with the "upgrade" Obviously not going to compete with the 10R hull in a wind, but boy; did it go. I also briefly tried a 10R rig on my Starkers and, once again, it was like adding a supercharger.

GB beat the 10R's with the Paradox in light winds, so could almost come down to where you sail.

Richard

[Derek Priestley 2]

Back in around 1997  I would have won the 10r Nationals at the Round pond as I was the top 10r.  Unfortunately I was beaten by a couple of Marbleheads!!!