Hi David,,
Your planing experience is very different from mine. On a short trick water ski, to slide the ski across the water sideways is much more drag than to plane with the ski parallel to the direction of motion. I used to water ski alot. Back in the old days, 1950's, when a 60 horsepower Gray Marine inboard engine was a big engine, the boats planed and they were long and slender, skinney boats. Look at old Christ Craft and Correct Craft power boats. They were all long and skinney because they had so little power to work with and they wanted to get the most speed out of their boats with limited horsepower.
As far as foils go, I'm glad to let Sam Bradfield fight that battle. He is a long way down the road from the rest of us and the trip isn't over yet. You don't see foil boats zipping around on 'real water'. They run good in flat water and strong winds but I don't know where to find that condition except in that ditch full of water over there in France.
Be careful of rhumors from guys in SA. A sailboat will always plane on its mid hull section out to its bow. The thrust from the sails is up in the air/rig at the CE and this creates a downward pitching torque which forces the boat to plane on its forward sections, like a seaplane. On a power boat the thrust is down in the water at the propellor. The thrust being generated in the water below the hull creats an upward pitching torque which lifts the bow and makes the boat plane on the aft sections of the hull.
Bill

Hi Carl,
Screechers and Hooters and Genoas all flown from the end of or the middle of a spinnaker pole are forms of 'poling the jib' as you put it. The old square riggers hundreds of years ago flew their jibs from structures called bow sprits, poles. For more information you might try a guy in Italy named Christopher Columbus.
Bill

The last report I received came from the owner of the first prototype, now sailing in Sweden. He told me the following:

QUOTE

...talked to the Catri folks in San Fransisco, they have new topspeed of 30.7 knots and continious runs at 28-29 knots for more than 5 minutes, with no reefing...

UNQUOTE

Dan,

Bill tested a planing hull once and as a result he decided not to use this feature in his designs.

In his post he described his test, noted that it was limited and that the idea could be put to work, pending further development and tests. He even offered suggestions on how to develop it. He is not bashing a feature only because it didn't work once.

Compare this to the other designer who tested foils once and now says that he doesn't use them because they didn't work at that time.

This is true, but not the whole truth. He tried only once, had limited experience with foils, probably did not have the resources for further experimenting, was not aware about relevant ressearches on the subject, etc. - all this is ommited.

The difference is that Bill told the truth with great simplicity, without fear of this affecting the sales of his designs, with genuine interest in the development of faster boats.

The other designer simply skiped those details, in my opinion only because it could hurt business.

Bill's posts on theoretical issues tend to be those of a scientist: totally unbiased.
The other guy's are those of an educated salesman: correct but partial or biased.

That's why I affirm that Bill's post says a lot about his credibility (no dictionary now).

Cheers,

Bill,

The moto of my previous post was your disposition to discuss and question features and ideas with objetivity, without omissions aimed to leverage sales. In my opinion this means that you are self-confident and honest.

Your sales-oriented posts are usually focused in "new ideas" which are actually your inventions or were already present in your designs 20 years ago. You fundament the claims with scientific objectivity but simple sentences, helping people understand the toys and tricks of our sport.

There are very few people who can claim to have invented and put in practice so many relevant solutions, improvements, inventions and ideas in sailing. Of those, even less are available for open discussion (and questioning!) of their ideas. I admire your work and your atitude.

Cheers,

Luiz...I got it now. Thanks for the clarification...Dan

Wouter thingy,
Why do you do things like this? You know that all you are doing is confusing some readers. You know that any beach cat can be made faster by increasing righting moment as long as the boat is not pitching moment limited. I know of no beach cat design that is pitching moment limited sailing to windward so on this point of sail, speed can be increased. Do you know of a beach cat design that is pitching moment limited sailing to windward?
On the SC20 by 20 we could double trapeze it sailing to windward standing aft on the hulls. Our feet were on a hull 20ft away from the leeward hull.
Reaching and flying a hull we would sit on the windward hull 20ft away from the leeward hull. We would not trapeze because the boat was near its pitchpole limit with us just sitting on the windward hull 20ft away from the leeward hull. We were still generating much more righting moment and sail thrust than a team trapezeing on a 12ft wide boat. Downwind the overturning/righting moment doesn't require the use of the trapeze, just watch the bows; trapeze out the back of the boat if necessary to keep the bows up. This is no change. So on two out of three points of sail you can make most boats faster by making them wider than the highway width limit. Making a boat infinately faster was only mentioned by you and as you know is not possible and only serves to confuse.
This wider boat thing sounds like an opportunity for invention to me, Wouter. Even your little F16hp could be made faster. How about a boat or a version of an existing boat for handicapped persons wide enough that handicapped persons could generate as much righting moment as a trapezeing team? Then they could race together, boat for boat.
Bill



AHHH, but reread the following phrase again.

“PS. I put a SC20 together once that was 20ft wide and it sailed fine. To windward it was a rocket. Reaching don't trapeze. Downwind same as a normal SC20, watch the bows.”

Don't you notice that little "Reaching don't trapeze" thingy ?

Why is that bit included ? Why can't you trapeze on this course ?

And Steve; I wasn't saying that the total volume of the leeward hulls needs to increase; just that the longitudal pitching restance needs to be increased in order to make effective use of the extra width.

What have you won when you've replaced capsizing with pitchpoling ? Either way you can't transform the sailpower that you have into speed.

But by all means guys, if you believe that you can make boats indefinately faster by making them wider and that no other design aspect will limit you gains to something far less than expected then widen your boats.


Wouter

I don't know if this has been mentioned before, but these wider boats (10',12', and up) have an important disadvantage. This is the fact that it takes more wind to get them up on one hull. And in most parts of the US/Canada in the summer the wind is quite light. So, a standard width (8.5') boat will walk away on all points of sail, everything else being equal, in light wind, say 12 knots or less.

Bill, can you tell us how much wind was required to get your 20x20' beast flying a hull?

Bill,

I think I may have the invention you talk about, I am building a four hulled "catamaran" this has the advantage that if the boat is built longer and wider it does not really increase in weight too much i.e the hull weight is the same in a 16ft version as a 20ft version. Just the gap between the hulls get bigger.

My calculations indicate that a 16ft boat has 15% higher for and aft stability (pitching moment) than a conventional cat, because the volume is in the four corners.

It is designed to go on a car roof rack, and because of the way it folds it can be made almost any width without any trailer width restrictions.

See the link for a drawing of one of my designs.
http://www.fourhulls.com/xcatdrawing.pdf

I would be interested to hear your thoughts on this design?

All the best

Gareth
www.fourhulls.com

Hi Dave,
There is no rule or law that says just because a boat is xft wide or 20ft wide that in light winds the sailors must sit on the windward hull and or trapeze from the windward hull in all sailing conditions. Both sailors can sit on the leeward hull and fly a hull in 5 knots. Both sailors can sit in the middle of the trampoline and generate righting moment using a 10ft lever arm. Both sailors can sit on the windward hull and hike with a 20ft lever arm and fly a hull in 15 knots of wind. Both sailors can trapeze from the windward hull, 20ft lever arm, and fly a hull in 20 knots of wind and go like a rocket to windward. Just because your boat is 20ft wide you don't have to use the full width until you need it. Just because your boat has an 8:1, or 10:1, or 12:1 mechanical advantage mainsheet, you don't have to sheet your sail in as hard as you can pull it and make the sail board flat in light winds. The same is true for righting moment. You trim the boat out to what you need for best speed. That goes for sail trim, fore and aft hull trim and righting moment trim.
Bill

Hi Gareth,
Good luck with your project. A four hulled quadramaran was built and sailed out of the Miami Y C for a few years about four years ago. I never saw it sail so I don't know anything about its performance or other characteristics.
Good luck,
Bill