small performance sailing dingy plans

No, don't be giving me too much credit. I built a Payson/Bolger Windsprint last year and have only been sailing since then, learning on the boat I built. Having just built a boat, I completely understand the desire/need to keep things as simple as possible and with a minimum of cost.

As for my diagram...

My attempt was to avoid the necessity of an extra foil on account of the canting ballasted fin mentioned earlier in the thread, so I thought of having a -nearly- pure underwater canting ballasting system with a more common fin keel. I probably should have labeled the centerboard a canting unballasted keel. The connecting rods for the ballast bar could be of minimum size and optimum shape to reduce surface area. The ballast bar itself could just be a flat heavy steel bar. Since I have played with a cheap arc welder myself, I could see putting that together fairly quickly and easily.

Based on my Windsprint sailing experience, I couldn't imagine not having some type of heel given the desired large area of sail. Thats why I added the counter canting keel ability, in addition to the canting ballast bar. The amount the keel actually cants is based on the keel axle diameter and the relative diameter of the driving belt gear. Both could be configured to get the correct counter-cant to offset the heel, keeping the keel at maximum effect to counter lee drift.
However, if the canting ballast bar could actually make the dinghy sail flat, the keel could become a simple fixed fin or daggerboard.

I envision the ballast bar rotating underneath/around the keel.
Based on the needs of the actual hull design, I guess the ballast, or bottom, bar, itself could be extended either forward or aft. If needed, the complete ballast bar system could be moved fore or aft of the keel. The only thing is to maintain the synchronization between the ballast axle and the keel axle.

And final thought I had, maybe replacing the lever with a fast acting electric motor if desired.

I just put this idea out there as it seemed more doable for a first time boat builder, based on my personal experience. However, what an individual's personal skills are really determine what is "doable" or not for a first time boat build.

If my idea has any merit and anyone out there with more skill in this area cares to develop it more fully, please do so.

 

Seems if the foil is quite effective at normal heel angles (up to say, 20 degrees), and a shifting ballast system is used, a centerboard, daggerboard or fixed foil would be all that's needed under the boat. The advantage of the fixed foil is that it can be moderately ballasted.
The question at that point is what value outside movable ballast has relative to an internal system unless it can be very long-armed and go considerably further beyond the beam of the boat than an internal weight (excepting interior design ergonomics).
Water ballast pumped from deck-edge to deck-edge has been done successfully already. It is not difficult to spread the water cavities for and aft a ways. Water pumps are simple and available. The cavities need only be a series of molded-in boxes (seperated so as to avoid sloshing, they could fill one at a time, so that cavities were either empty or full).
Of all places on a small cruiser/racer, that area is most available to give up inside space, especially if flared (which would put the weight out furthest).
A twenty-footer with a nine or ten foot beam (at deck level) would be ideal for this application. Topsides like a J-24 (in fact a J-24 or a 22 wouldn't be a bad boat to do this to. Replace the keel, reducing the weight by maybe 1500 lbs and put a foil dagger through the cabin roof. Add 1000 lbs of movable water ballast. The 500 lb reduction in weight and the improved sail-carrying capability might make that boat very fast. I would maybe opt for a good powerful truck starter motor to run a big piston pump for super-fast ballast exchange. One battery would last a long time given the minimum time it is drawn from. A solar panel could recharge it.

A.

 

Well, I think t's very, very much easier to have the ballast inside, then it's heavier also, 10%(?) if it's lead.

 

How do you calculate that, Raggi?

 

Performance

This is a very rough sketch of a monohull whose length could be from 25' on up using a 110° canting keel and a sliding waterballast tank.NOT a cruising boat.....
(Sketch by nflutter)
attachment.php?attachmentid=12546&d=1176896587
Address:
----------------
And here is a smaller version complete with its own movable ballast(mostly water):

http://www.rohanveal.com/photos/italy_07demo/d2x0634.jpg
---------
Just a note about building a Moth: you can buld a foiling Moth for around 7 grand with pro ready made sails and foils.....

 

One liter of lead is 11kg. In water you have one kg buoyancy, so it's only 10kg acting as a downward force, or 100N if you like. Approx, of course.

Then you have the drag and wetted surface.
The sketch above seems like a lot of work, and what is the gain?
The lead would do a better job and create no drag if it was inside the boat.