I like your idea of having ballast in the extremes of the hull though. But I'm not sure it's necessary. I think Rob's philosophy is to make the boats long and wide instead of using ballast. Then the boat has the same righting moment and "pitch resisting moment"(?), with little extra weight, and without carrying the stronger/heavier mast/beams required if the boat is to be strong enough for ballast. The longer hull will have more wetted surface/friction though, meaning there might be a tradeoff regarding the use of ballast to increasing the length, though.

A large rig is to reach decent speed in light wind. In strong winds, a large rig would operate at a low coefficient of lift, because it's unnecessarily large. A smaller rig can create the same force with a "normal" coefficient of lift, so the boat will probably go as fast, but will less heeling and pitching. (Or as Rick has calculated, faster in some cases.) To operate the large rig efficiently (without collapsing the luff for example) at a low coefficient of lift, the rig has to be stretched flat (low camber), which will take some effort. The large rig is also more sensitive to gusts and steering mistakes. The smaller/reefed rig is easier to handle in that regards. So now we are connected to your discussions about reefing from earlier.

If the rig can be reefed without decreasing the aspect ratio, the proportion of induced drag from the top/bottom of the sail will not increase by reefing, so the L/D will not get worse. This is the case for a triangular sail, but not a square top if the reefing is done at the boom. But if reefing would be done by rolling the sail into the mast or around the mast, a square top sail would increase the aspect ratio. So that might be a nice option, if it can be done in practice on a HP.

Bernd Kohlers Tiny Tri has a wishbone boom, and the sail is reefed by rolling it around the (windsurf) mast. To accomplish this, the boom is not attached to the mast, and battens are diagonal/vertical. So that sail actually increases aspect ratio when reefing. The first reef(s) makes the sail smaller and more triangular but with the same span, which increases the aspect ratio. And for the following reefs, the aspect ratio is constant since the sail is triangular from that point. I guess the challenge in practice is to make it possible to set an efficient sail shape in all situations.

It should be mentioned that the L/D of the rig is not all to it. The L/D of the whole boat might get worse with reefing, since the drag of the boat/structure itself is now a larger proportion of the total drag. So it's not easy to say what is optimal. But with an increasing sail aspect ratio during reefing, the L/D of the whole platform might stay constant for the first reef(s), which would be cool. Then there would be less of a penalty to carry a large sail for light winds, and having to reef with a less efficient platform as a result, compared to having a smaller sail made for stronger winds in the first place.

I think!

/Björn