| 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.

Wahoo!
Do you see a better way to encourage the hull to plane?
How much weight do you think would be needed to do it?

| 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.

Meh. It would be the weight required to assist planing. Its not like it would challenge the max load of the structure or would even be noticeable at the water line.

| 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.

I was thinking the amount of force needed to go faster was the

| The penalty in speed for lacking righting moment or pitching moment (which is limiting the sailforce) is not huge, since the relationship is not linear. The frictional drag of the hull is proportional to speed squared, so every increase requires two increases in drive, meaning a decrease will not make as large a decrease in speed. Also, the apparent wind angle at a higher speed comes more forwards, meaning less drive.

Rick said that sail drive to windward was limited by righting moment (only 3 crew).
Rick has generously gone through the scenarios after I (we?) bugged him about that.
The conclusion is that more weight to ww is unlikely to help.

| 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.

I thinks Robs real innovation is to realise that glass foam core can be longer and wider cheaply. And that is cheaper to go longer and wider than any other option in boating. That wood cannot go as long and wide as cheap, light, and strong as foam can.

So ya, longer wider, low weight. At this point the water ballast IDEA has morphed stern ballast for planing assistance of those nice flat bottom hulls.
But lets be honest, it's weight was never gonna challenge the structure.

But, and I know nothing, reading some problems Rob had with managing BL single handed, I wonder if BL had a ballast tank to make it a little more sluggish, wind resistant ,and docile would have helped handling at low speeds/moored. I wonder if Steinar should consider it.

| 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.

Rob said prior that sailors don't like to reef because reefed sails are lower performance and this reduces pointing.

You and Rick are saying reefed sails can go better to windward.

Perhaps it is apples to hand grenades. Typical boats and reefing while pointing are not HP's and reefing while pointing?

| 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.

But given I am reefing, I have too much drive. If I have too much drive, why do I care about l/d? Why put extra work into maxing l/d of a reefed sail?

But honestly, add 10%? to the mast height and point the sail up. Watch your planform efficiency go up and induced drag go down. And reefs on the bottom wont effect it much. Bell shaped ftw, right? Never understood square tops. Especially with flexible masts.

| 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.

But we are kinda off in the theory now, right? Ya, the planform and AR increase as you reef is nice, but then the nose and camber and all the other wing details become larger and larger portions of the system performance. Not to mention induced drag is not that big a deal at low loading, right? Not that much energy to power the vortex?

And you are still triangular, and not bell shaped.

| 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.

IIRC, getting to a AR of 7 was pretty much the top of the curve. So if the sail is going from 4 to 5, maybe.

On a HP I am more inclined to go big and cheap. So If I have to choose between a complicated mast roller sail and cheap junk like huge sails, I'll take the huge junk, thanks. Simple ugly reefing wins for me.

Again, if I am reefing, I don't see how I care about the l/d any more. Except I guess I can't point as high and loose some windward performance?

But I know nothing.

| 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 don't see it as a penalty. If I got a large sail, I can sail in low winds. If the winds get high, I reef, and care not much for l/d, because I have too much power.

I think!