Reply To: How much does your mast bend?
Hi Bill,
I think you are probably trying to find an answer that doesn’t exist. It used to be more simple because the Old Needlespar metal masts although different in stiffness would generally have the same type of curvature. So you had a direct relationship between sideways stiffness & helm weight (ish).
If you look at the type of rig Nick & Jim developed it is very stiff & powerfull. I believe this rig is targeting optimum performance in force 2-3 conditions (which is typical for 70% of summer championship races). Less than that you rely on your ability to chase the Zephyrs, more than that you rely on your superior fitness to keep the boat flat & driving. The Proctor North Rig is really quick in Light-Medium conditions, but really difficult in a breeze if you are not super fit, or you are less than 85kg (or both). I think Steve Dunn proved that at last years Champs. The trouble with the Proctor is it does all its bending in the middle & is too stiff at the top (similar to a finn rig, but a finn mast needs to do this as the sail has no roach so it is the only way to dump the power in a blow). The Ceiliah mast has more going on at the top which allows the leach to open up more readily, so the bottom can be stiffer sideways.
If like me you are not super fit & don’t spend half your life in the Gym & the other half on the water then you need a different solution. I tend to use a softer mast which targets a wind range of force 3-4, that way you can bank windy weather performance but may not have an edge in light/medium conditions particularly pointing in choppy conditions (as i think you metioned). You do need to nail your starts to make a softer rig work.
What is clear to me & i have measured & played with a lot of different masts. If you make a Carbon mast with the same bend numbers as your favorite Alloy mast it will be too soft. This is probably due to the fact that you can make (& should make )a Carbon mast bend below deck. It is also due to the speed at which a carbon mast returns to its original shape (gust response).
All this is ignoring the effect of sail shape, but i have probably rampled for long enough this time.
