Been nutting this out in my head for a while hope some of you might be able to use it or have a laugh at the least!
My automatic canting keel system has only been bench tested so it’s not proven as yet so you’ll have to forgive me for not having photo’s or more detail but here goes… (hope i get the picture across without too much head scratching)
Set up canting keel in any configuration so long as you have a motor/winch to cant it. most boats will have (if not will need)a full bulkhead running athwartships. Place a bearing (you can get very small ones off router bits used as guide rollers) at just below deck level on the cenre line and hanging from it a stainless rod weighted at the bottom (picture a pendulum on a grandfather clock). also attaced to the bulhead are two hair trigger microswitches opposing each other fastened into adjustable position holes.
The “theroy” is - every boat has a optimum heel angle to sail at its best, by positioning the switches just past that angle when the boat heels past it’s groove the pendulum strikes the swich activating the motor canting the keel to level her out, when it returns to the groove the pendulum releases off the switch. Tacking or gybing simply makes the pendulum strike the opposing switch reversing polarity or activating reverse gear canting the keel onto the other side. simply a matter of making gravity do the thinking for you keeping the boat as best it can in the heel range you set by the position of the switches on the bulkhead. Although… i do know of problems with the system such as if we’re sailing along in 10kn and the keel has set itself up for that and you get a lul of a couple of knots the boat could right too much even to the point of inducing negative heel, a way around this is to have a motor that creeps slightly but that in itself could cause a problem by causing too much keel movement ( but that could actually propell you like rocking a dinghy) anyway something for you all to chew over I’m sure you can come up with your own pro’s and cons and probably perfect it alot (if someone hasn’t already done it). What i do love about this system is it dosen’t require a extra channel and you can watch for shifts and concentrate on sailing rather than worring about your cant angle (although that in itself would be fun also).
love to see some input on this, criticism welcome.
Another idea i’m toying with is a keel that also cants fore and aft in a kild of ball and socket setup, using the same pendulum idea this could sense nose dive and cant the keel aft bringing the CG further aft to reduce the foreward trim. this would mean going to the older syle keel without a bulb to reduce drag in a aft canted position. A carbon top section and lead bottom would fix this but the trade off may not be worth it. - like i said only an idea but without ideas we’d all be sailing square riggers! (in fact not even that)
ps I know it’s been done before but i couldn’t find much info on it so it’s here for those can’t either(perhaps i just dont search properly though)[:-banghead]
Sean, very interesting ideas! When you set this up on your boat at some point try it manually-moving the keel by radio-its one of the great thrills you can have in rc sailing and is quite easy to get used to and feel in"tune" with. You feel like you’re ON the boat–its worth trying along with your other ideas!
My suspicion is that the micro switch system may be prone to oscillation but you won’t know until you try it.
Pivoting the keel fore and aft is definitely worth considering. If you use the side view of a hatchett as a starting point you can see that the business end of that shape could be refined in such a way as to have most of the weight down low like a bulb but shaped so that it could take a 20 degree or so angle back w/o causing more drag. The downside is wetted surface as compared with a bulb…
Have you designed and built your boat yet? When do you think you might sail?
–High Technology Sailing/Racing
I agree with Doug. I think your system would be prone to underdamped oscillations.
You might want to consider a gyro instead. There are plenty of small lightweight aircraft gyros out there that could be configured to replace your pendulum and will be a lot more stable (less susceptable to intertial effects). If you want to get really tricky, you could incorporate a damped control circuit into the loop (either analog or digital) which should give you a rock solid response.
I don’t think a gyro will work satisfactorily . But if you experiment with one you might consider trying a “Heading Hold” gyro. You’ll need to buy or borrow the gyro and send it to Rob Guyatt to see if he can match it to one of the new super fast winches. In the past all available winches were too slow to work well.
What may be the solution is an accelerometer tied in with some sort of microprocessor that has the capability of being programmed for reponse time and programmed to hold a specific angle of heel ON EACH TACK. Basically, it seems to me that an automatic system should perform just like an “ideal” human crew. On a canting keel boat I imagine that te right electronis/computer due could knock it out pretty quickly.
On a multihull the Power Ballast system has to move in twodirections but that shouldn’t be too much more complicated.
But I just have to reiterate: try sailing manually before you spend any money-you can’t lose and you might find out how much fun having stability at your fingertips is!!
At any rate good luck; any recent progress?
–High Technology Sailing/Racing
The limit switch idea will certainly result in negative heel before the keel moves. One switch is at ideal heal angle, the other switch will need to be set at ideal heel angle on the opposite tack. When the wind lulls the boat will have to go to negative of ideal heel angle before the keel will move. The only way around is to have 2 sets of switches and a servo operated switch wired in so that it only one set is actively controlling the motor on a given tack. Then you could do a narrower range but you’d still have to figure out when tacking how to get the keel into the range of the 2 switches since it would be “out of bounds” at first with nothing activating the motor.
In the early stages of the design work for my F100CKTF boat I looked at automating the canting mechanism, by using a pendulum weight swinging from a potentiometer/rotary encoder which then be connected to a servo driver and to the winch. I could see some problems with the pendulum continuously swinging due to the rolling to the boat athwart ship driving the keel so the whole system would be hunting. So I looked at (a) mechanically dampening the pendulum in a light oil (could be messy), (b) electronically dampening, © stepping potentiometer say 5 degrees steps equaling 10 degrees of keel cant. I received some good advice from Rob Guyatt at RMG Winches on possible circuits, but I decided to put this into the later development basket, so I going to control the keel from the transmitter to start with. And now back to the workshop to try to finish the project.
I cant see any advantage to this to be honest unless you can also do it manually when you want to. You wont be able to roll tack for starters, and also to make bearing off smoother a bit of windward heel tends to be a good thing, you wont be able to do that. Just some considerations for you!
Luff 'em & leave 'em.
I have recently finished my F100 with a canting keel in it and have been sailing it quite a bit in between altering bits and definately think that you need to be able to control it from the transmitter other wise the boat will be to jerky and sailing in a small chop which most lakes produce will be very hard work and you will end up with the boat heeled to wind ward in the lulls while the pendulum is trying to correct itself. When it is controlled from the transmitter you can see the gust and so forth on the water and be prepared for either more keel angle or less in the lulls.
The self canting system does have it merits but it will require alot of work.
Gappy I sent you ane-mail but I’d like to publically welcome you to the forum and congratulate you on having the FIRST sailing canting keel equipped F100 that I’ve heard of. Would you please post under New Classes a new topic: “Sailing an F100” and when my new boat is done I’ll post there as well and maybe John Beavis will also post there when his boat is done.
Lots of technical questions as well like how do you have your radio set up;which stik/direction for the keel; what kind of lateral resistance are you using; what kind of set up for the canting keel in terms of its instalation in the boat-watertiteness etc.; what cant angle.
Perhaps you could start a new topic in this section:“Technical aspects ofthe F100” (these new topics are IMPORTANT so people can find your info easily and info on the F100 easily) or something like that–or just post it all in one place- but whatever you do please share the info-many of the peope who use this forum would love to hear your story!
–High Technology Sailing/Racing
Doug thanks for the welcome
Not sure how to start a new topic so may be if you start it I will feed some info onto it.