[alloyed2sea]

This time in the sailing arena:
http://www.cbtfco.com/wrapper.php?page=pages/tech.html
Great times!

[AMG]

Rather a break-off keel.... in the recent Sydney Hobart Race the 98´SuperMaxi Skandia jammed and finally lost her kanting keel and now again in Vendee Globe outside Brazil the smaller 60 feet Skandia lost her kanting keel;
http://www.nickmoloney.com/nick.asp?artid=2207

[alloyed2sea]

The price of progress?
But not a good day sailing.
Ever been aboard one of the "canters"?

[AMG]

Never been on a boat with that kind of keel but on this one, called One 40, which has both ballast or trimtanks each side under the cockpit and a ballast weight on a rail under the main salon that slides from side to side. If I recall right it is 700 litres of water and a 700 kg weight. Very special design as always by Guy-Christer Lönngren and she is a fast sailer. Interior is like a spaceship and very elegant. I can sell it to you for USD 200´

[alloyed2sea]

Looks VERY fast and rather alien.
Currently don't have room at my marina right now - but perhaps the Romulans (Star Trek) might be interested.
Does it carry any heavy photon weaponry?

[D'ARTOIS]

The canting keel is a keel that swings from port to starboard and vice versa. For obvious reasons the keelplate is very narrow and needs the yacht an additional lateral surface(s) to cater for the lost surface on the keelplate.
Apart from the disadvantages - and they are there - the advantages are in such a way that the addition of the CB and/or CBTF is rather a must in order to remain compatible and competitive. Specifically at maxi yacht level.

The reason for the numerous accidents with regards to the technical execution is simply the fact that one has to learn and the material (read metal) knowledge of designers knows also its limits.
The bare fact that the canting keel allows for an increase of 50% percent in SA or a decrease in ballast of also 50% is an advantage that cannot be neglected.

Using the right kind of metal and with adjustment of the dimensioning of the metal- and hydraulic parts and mechanisms, also these initial problems will finally be overcome.

[YachtForums]

Without researching this, can I assume the keel not only swings from side-to-side, to increase the leverage of ballast, BUT ALSO... adjusts it's angle of attack relative to the water flow to provide downward pressure on the foil, thus adding artificial weight? If this is true, it has GREAT merit!!!

If the pressure generated by the foil exceeds the mechanical and structural tolerances of the articulating mechanism, possibly TWO smaller foils could be used (fore & aft). Two keels, that turn in seperate directions could substantially aid in tacking as well, as evidenced in the dual rudder system.

[AMG]

I have had the same ideas since 30 years, and watched other test it out. The kanting and tilting keel slows down the boat too much since it is energy used. A wider fin could take advantage of the water pressure but again, more friction that consumes energy. The dual rudders, fore and aft, is good for matchracing but not for normal tacking as they also will slow down the directional speed.
This is my 2-cent....

[Doug Lord]

Canting keels are probably one of the most significant breakthrus in sailing yacht design in the last 50 years(along with the Moth foiler!).
They have been around over twenty years and have an excellent safety record and an unmatched race record. Even with the individual component(fins, bearings ,rams) failures recently and perhaps a design failure on a couple of boats all the major ocean races of the last few months(years?) have been won by canting keel boats including the Sydney Hobart, Pittwater Coffs and the Vendee Globe. The upcoming Volvo crewed round the world race will be won by a canting keel boat since all of the boats have canting keels!
CBTF is a patented system whereby the keel fin is reduced to just being a strut and doesn't develop ANY lateral resistance at all. The lateral resistance function of the boat is 100% taken care of by twin fore and aft foils that the CBTF guys call foils and not rudders because their main duty is to develop lateral resistance. When the two foils are turned in opposite directions the boat turns in a turning radius about half that of a "normal" canting or fixed keel boat-making for quicker turns and better manouverability than a conventional fixed or canting keel boat. But the biggest advantage of the CBTF boat over other canting keel boats and over fixed keels is "collective": when both foils are turned the SAME direction upwind virtually eliminating leeway in regards to the hull and allowing a better VMG to windward than just about any other yacht.
Future canting keel incarnations will see hydrofoils used to lift the boat with a flap on the canting keel fin to increase righting moment.
All in all canting keels represent one terrific way to go fast in a monohull with a lot less lead than a fixed keel raceboat!

[AMG]

Originally Posted by Doug Lord

But the biggest advantage of the CBTF boat over other canting keel boats and over fixed keels is "collective": when both foils are turned the SAME direction upwind virtually eliminating leeway in regards to the hull and allowing a better VMG to windward than just about any other yacht.

Hi, nice with a sailor here! I know that this system (the foils/rudders) was used in the Americas Cup long ago, but does it really work over a longer distance, or is it just to gain height in duells?

[Doug Lord]

CBTF wasn't used in the AC but twin foils were used. CBTF is Canting Ballast Twin Foil. The twin foils did show promise back then.
Any course that has a lot of windward work will be particularly beneficial to a CBTF boat ,but they're good on any course-at least according to their results and the CBTF guys I've spoken to.

[AMG]

I know this canting system was not in AC, those foils were more often combined with wing keels. Another question, when you go downwind with a canting keel, is it better to go quartering (tacking) than almost straight to your mark?

[Doug Lord]

Depends on the boat but many modern light displacement boats canting and fixed can benefit by gybing downwind.