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Motion of the water and the effect of the increased mass moment of inertia as water is added might have made it harder for Alinghi to steer the boat, but that wasn't my impression as I watched. The rapid changes in direction were not continuous as you would expect if it were a yaw stability...

Someone who knows This would be a good time for someone with high speed multihull design experience to comment. Otherwise I think we descend permanently into discussion of history we can't change and the ethics of people we don't know. Even uninformed technical speculation seems better than...

Speed? No wind! We appreciate how incredible the performance of these machines was and we really understand what it takes to travel the speeds they do. However, we are not really the target audience. The best show is the contest between two boats fighting each other for every advantage and...

The limitatioms of common sense There was, or is, a high performance multi-hull racing class. F40's? Anyway, I've heard that tri's were proven faster there. I don't disbelieve this, or understand it. RHough talked about the advantages of the tri. I separate them into two categories -...

Assumptions Two assumptions I made were challenged and I have to admit, I was making assumptions. The first was the requirement for match racing. I think this is what the DOG specifies, that is one boat from each club. Even when the NYYC was twisting the intent of fair competition into a...

OK, based on Bill's post I'll try to talk about design here. I'm going to base this on my memory of the two races and sprinkle in a little from the press conferences and I guess it will include sailing these beasts, not just designing them. This is obvious, but in both pre-starts it was...

Freemantle or Hawaii The best AC cup viewing was in Freemantle. There was wind, the boats were bashing through the waves and the crew was working hard. More recently the races have been sailed at venues with lighter winds and that's what the boats were then designed to handle. This time...

AC design I thought there were some interesting lessons on the comparative design of the two boats and this is BoatDesign.net. This particular tread seems focused on non-design questions. Should I start a new thread? Peter Raymond

Didn't Monty Python do this better?

BoatDesignCredit.com I've enjoyed most of the recent discussion about who should get credit for the cheater Australian boat, although it has been something of a guilty pleasure, since it's only peripherally related the topic of designing boats. Of course, I was going to mention that, as I...

Similar things have been done and worked well. A lot of the speed sailing boats use various tricks to prevent overturning by aligning the under water and above water forces. Sail rocket is one example. Your Bruce foils will have to get further apart as the mast gets taller, but that's a...

Tris tend to have relatively low volume amas (sp?). Alinghi seems to have lots of volume in the hulls and to sit pretty lightly on the water, or to have a lot of rocker so the ends, particularly the bows, sit high. In the typical tri flying two hulls the ama is pretty loaded, but Alinghi's...

I did mean Alinghy when I was talking about straight foils. Of course now we all talk about how their design seems messed up. I've been surprised that even flying a hull the bow is sometimes out of the water. After using those tricks to lengthen the water line, it would be nice to use it...

The idea of water ballast is to have no more than you need and only in the windward hull. Then, in light air you have a light boat and in heavy air you can maintain the efficiency of the sail. Standard techniques to depower a sail, like twist, increase drag, which is always a bad idea. I...

I thought maybe USA-17 sails upwind under wing alone in stronger winds and they maybe just dropped the jib a little early. That might have been in preference to switching to a smaller sail. I also thought that it might just have been using Alinghi for 2 boat testing. When the wind picked up...

True, but if they were 100% carbon they would be stronger and stiffer than they need to be. In that case you could keep the same profile and net area, but increase the span and decrease the cord. Induced drag is proportional to span squared and is also the dominate drag component at low...

wood foils Carbon is certainly not a requirement. Wood isn't as strong or stiff though so there will be some performance hit. Wood might match the low speed, or high speed, performance of a carbon foil, but not both.

Doug said: "It might be worth asking Jeff-the owner/moderator if we could have a "sticky" post at the begining of the thread that has references gleaned from the thread and other places posted and doesn't move." I'd like to call it "teach a man to fish", but "design resources" might be more...

Learning OK, I've gone through 61 pages. I'd feel like I've followed foiling from it's birth, except that I remember when Longshot and Yellow Pages were the latest hot boats and Russell Long had the prototype Tri-foiler at the Atlantic City sailboat show, before he joined Hobie. If I'm...

Timothy said: "...If the arm that supports the arm along with it's attendant bulb is above the water(pacific proa) the same righting moment is achieved with less drag and if you switch the bulb for a float(atlantic proa. catamaran) then you save weight as well.." Actually, underwater drag is...