Backman 29-Innovative Canting Keel

I ran across this boat earlier today. It uses wings on the canting keel bulb that are "adjustable". Nothing I can find says what is adjustable: angle of incidence, sweep or?
Appears to be a damn good system for developing the extra lateral resistance required by a canting keel boat w/o having an extra daggerboard or rudder take up interior space.
Can anyone in the UK(or wherever) with knowledge of this boat comment?
See the top most article here:
http://www.sailinganarchy.com/

[the_sphincter]

check out the 79er facker

Oh yeah-they use an old fashioned bulb shaped like a wing-like Procyon did 20 or so years ago. Bethwaite's cool but behind the times on this one....

[the_sphincter]

I guess bethwaite's thing is that it will work partially canted because a portion of it is vertical

That's the whole point of this thing! Andy Dovel pioneered using wings similar to those on ACC boats on a canting keel-first on Atomic. His were fixed but had the same advantages Bethwaites, Backmans and Procyon have: they don't take up room inside but add lateral resitance when the keel cants.Of course they have different levels of efficiency..And CBTF may still be the best lateral resistance solution for high performance canting keels.
The thing is these(Backman's) are touted as being adjustable: adjustable how? Incidence? sweep? area? Sure would like to know the answer(s)!

[RCSail]

I agree that that design is rather innovative, and could find good application in a fast cruiser or related design due to the economy of space. I do see, however, one difficulty in its application to racing boats: the angle of the wings. When angled so as to reduce leeway, they would also produce a strong downward force unless the boat was heeled considerably. Additionally, unlike a VOR style daggerboard system, the wings cannot be retracted to reduce wetted area.One definite advantage that might outweigh those concerns is the fact that the force would act directly on the center of gravity and prevent the added heeling force that both daggerboards and CBTF adds. I believe that daggerboards might be the most efficient for boats designed for heavy wind conditions when some degree of heel is expected on reaches, and they also add the benefit of being retractable. CBTF might be the best when little boat heel is expected, but when the boat does heel you add the inneficiencies of a non-vertical foil to those of a symmetrical foil.

Well, I don't know for sure that these wings don't retract.In fact I'm very familiar with a patented system for canting keels that DOES have retractable bulb mounted foils! But so far I haven't found any details about this system.
CBTF is designed for use on high cant angle canting keel systems and is less effective on low cant angle systems like the VO70's for example. And any system using wings would be hard pressed to equal the upwind ability of CBTF using collective.
The Backman foils either change angle of incidence or they sweep back and may even be retractable-just don't know yet.......

[RCSail]

I agree that this would be much improved by the use of retractable variable-incidence foils.
I still feel that the use of a symmetrical foil for controlling leeway is rather inneficient, although I do agree that as long as heel can be almost eliminated through the canting keel the CBTF becomes quite competitive on a reach. I still see the retractable daggerboards as being a somewhat more versatile option for outright racing boats because of the advantages in whetted area when sailing closer to the wind.
I still do like the winged keel system for an all-around boat that does not wish to deal with the interior space difficulties of either daggerboards or CBTF. (and the deck presence of the daggerboards is a liability, as proved by the injuries onboard one of the VOR boats.)

[D'ARTOIS]

Double or single ram? Who is the Mfr? Is there a picture available of how the system is positioned?

For example, bit by bit I begin to understand the system:

Cariboni supplies a subfram that contains two frames and between those frames is the keel positioned, that is mounted in two subframes.
Cariboni says that two rams are an absolute requirement; it gives a 100% backup margin: if one ram fails, the other one will still work.

I have received a few technical drawings from Cariboni but my autocad fails to accept the drawings.

Most of the details of the design of this boat are still unknown including what exactly is adjustable about the bulb wings.
However, what is known is that the wings are"hydraulically adjustable". If you stop and think about that for a moment it becomes apparent that in order to do that they must have either a shaft or pushrod or hydraulic lines running down the length of the fin. Bound to be some interesting engineering involved especially in sealing the canting system.And keeping the fin strong enough.
But I still need to find out what the "adjustment " does to the wings......

[D'ARTOIS]

Cariboni, I believe the largest manufacturer of the hydraulic systems for the canting keels, uses the hydraulic experience of HOLMATRO, a Dutch company that might be the largest supplier of hydraulic systems world wide.

Is the Cariboni system used in the Backman 29?

[Raggi_Thor]

I have asked the Backmans for more details. This is quite interesting :-)