Changes at SCHRS

Racks will be included in the calc of "beam" to get a "righting moment"

I take the point about encouraging racks, my worry about using overall beam is if we assume the pivot point is the downwind board (plate, skeg) then boats with wider hulls, for example a shearwater, have a narrower effective beam. You then need to get more complex by using the waterline beam for the boats righting moment and the total beam (or distance from the downwind board to the trapeze 'artists' feet i.e. (total beam + waterline beam)/2 ) for the crews righting moment.

It's all a bit fanciful anyway as most boats are designed to be powered up in a similar wind range, with the sail area dictated by righting moment and the SCHRS already goes to great lengths to calculate sail area.

One good thing though, if boats start to get narrower because beam costs on handicap then perhaps I can forget the diet   as a couple of extra stone on the wire will come in handy.

Steve

Congratulations and well done for taking up this thankless job, It's good to see some life coming back into SCHRS, it has a solid foundation with a few very small problems. Looking forward to seeing how the A Class rating comes out, 97 to .98 is just too hard to race to, have a look at the results of the Round Texel for a good guide to the circular random results of the different classes and the elapsed times.

All the best. Rob

Simon,

You'll have problems finding a rule that works across all wind strengths, light boats will do well in less wind but wider heavier boats will be powered up later but will stay powered up longer. Here's a starting point for a righting moment factor:-

Boat Weight * 1/2 beam

+ (number of crew * beam + number of trapezes *0.9) * crew weight.

The first part is the righting moment of the boat itself, we should really use the distance between the two waterlines instead of the total beam. To which we add that of the crew, if they sit in then their righting moment is beam times weight, if they have a trapeze then we say their c of g is 0.9 meters further out.

You'll then need a fiddle factor to bring the numbers back into line, F18 are the most common boats under SCHRS and they come out at 735 in the above so we could use that as a fiddle factor to give:-

735 /(WS * B/2 + (NC *B + NT*0.9) *WC)  

This will of course penalise the wide boats doubly in light winds as not only will the rating go up but they tend to under perform their handicap then as they can't unstick the windward hull.

It's only a start

Steve

 

Simon

Yes, I'll be at the East Coast Piers Race.

Cheers

Bob