ConradQ, thanks for your comments.

You said:
On the soft mast issue, if the mast is too soft, it bends in the middle. I have a carbon A-Cat mast that I have to add layers to to get it stiff enough to get power in anything above about 5 knots of wind. Currently,I have to be real careful to not sheet in too hard as this pulls the sail down the mast, bends the mast more, and removes all my power. It is a pretty fine line between having too stiff a mast and too soft a mast. ... when I would sheet in hard, the sail would pull down, the mast would bend, the top would twist off and there was no power

I would have to agree that it is possible to make a mast too soft or not match it properly with sail cut and that it is a fine line between too soft and too stiff but it seems that if some care is taken during the design process this could certainly be done properly. It's probably just easier for some manufacturers to go with a stiff mast and not worry about getting it right, but this does mean the crew has to work harder as a result. Also, with a softer mast, it is possible to depower it out of it's groove and this would be a problem if the designer made the mast too soft in it's middle. That's why I brought up the topic of tapered masts - seems like it makes it easier to keep the mid mast stiffer and put the softness where you want it at the top. I would think that if the sail and mast stiffness are matched right, the top of the sail would twist off with downhaul or gusts but the rig wouldn't be depowered by tensioning the mainsheet as you describe.

This brings up a related issue to my original post on softer vs stiffer masts related to tuning spreader rake and diamond wires on stiff vs softer masts. Once a decision is made to go with an overall stiff mast instead of a softer mast by a designer/manufacturer, I would think that this decision limits the ability of the crew to tune the mast.

With a softer mast you can adjust stiffness and prebend somewhat independently. For example, you could tune mast stiffness for crew weight but not prebend athe mast allowing you to depower interactively with downhaul and still have good overall rig power and automatic gust response.

With a stif mast, you can't make it less stiff with spreader rake and diamond wire tension, you could only make it stiffer (what's the point) or set prebend. Once you prebend you've limited your ability to power up the rig. I would think this approach would be limiting when conditions change, ie, most of the time.

So it would seem to me that a stiff mast has limitiations for how a cat can be tuned and sailed by the crew: you can't tune mast stiffness, you need to work harder playing the mainsheet in gusts, and you don't have much of a range of downhaul to interactively depower overall rig power and instead must live with whatever prebend you guessed would be the best comprimise. Finally, I would also guess that sails might last longer on softer masts than stiffer masts since stiffer masts would put more strain on the sails due to their inelasticity, particularly when the crew tries to make the downhaul do something by really cranking on it.

Jerry