Movable ballast An idea I've had

I am thinking of designing a movable ballast either “microsail” principal or the “swinging helmsman” on the skiff I have seen, however having its operation automatic ie not radio controled. I think it would be very simple to do with a conventional servo winch and a servo tester circuit. Instead of turning the pot on the tester by hand, a small weight is attached to the pot. Any thoughts, would it break any class rules in “restricted to two channel radio” classes. I am going to build the circuit and test the principal.

P.S. Awaiting flak on swinging helmsman, I couldn’t think of another way to describe the poor bloke/chick:smile3:

the movable ballast in my opinion have some interest if the “movable action” is not often required. With classic IOM , M, EC12, etc. classes where the change in direction is so often required, the avantage of a “movable ballast” become an serious handicap, specially around the buoys , because the changes of ballast position requires relatively a lot of time .

Hi claudio,
do you mean that the ballast is to slow to react to chances in trim. If the ballast moved quickly enough, would that solve the problem you are describing. How quickly would the ballast have to move.
I am actualy at the moment trying to solve a problem with the potentiometer in that a standard one is too tight to move freely by a small weight, it tends to stick. Does anyone know of a “pot” that moves freely.

two elements need to move quickly : the servo driving the ballast and yourself in passing the correct command.
Often approaching the buoy there is an amount of boats that change directions continuosly in a couple of meters and even less. You have to responds in changing direction to : a) giving the right command if you knows where the ballast is and b) whait that the ballast has moved.
Under these circumstancies, should be better to fix the ballast in the middle, let the stormy situation clear up and then re-adjust the ballast has you prefers. You have to define a strategy which shall move first the ballast or the rudder ?
Short pahts are not good or suitables for movables ballasts.
Up to you.

Hello again,
The Idea i had was to make the moving of the ballast automatic with a sensor that detects the heel of the boat.
“Short pahts are not good or suitables for movables ballasts.”

Do you mean here that a fairly long track is required for the ballast? If so how much more than the beam of the boat do you think is nessesary.

Another thing is that in skiff sailing or with manual control, you can anticipate the need to move, This may be a problem in that because my idea reacts to rather than anticipates the movement of the boat. What do you think.

Hi Nick

Would be very interested to hear how you develop your idea. Some thoughts:

Some damping of the weight’s action might be needed, otherwise I can imagine the servo wearing out with continual hunting as the boat moves through waves.

The degree to which the weight turns the pot indicates the amount of heel, and so the amount by which the ballast moved would also depend on heel. This would be very attractive for some other applications, such as for a fin trim tab on an ‘A’ class I’m thinking about.

As Claudio mentions, the system might require a third channel on the Tx which at least disables or switches off the system and returns the ballast to neutral. Better, the third channel might provide a degree of mixing, so degree of ballast action could be set in a range between zero through moderate to full-on.

would it break any class rules in “restricted to two channel radio” classes

Depends on the exact wording of the class rule. In the IOM, for example, a third servo would probably fall foul in two ways. If no third channel is used, then it would be a fitting with ball bearings (because it isn’t part of remote control equipment), which is not permitted. If a third channel is used, then it is controlling something apart from rudder and sheeting, again not permitted.

I have the circuit working on a breadboard, it is completly independant of radio control at present, in answer to Lesters comments with regards to a 3rd channel I am at this stage not sure how to interface although a programmable aileron mixer may work?
The damping is also a problem, at the moment I have 2 kinds of pot, one is the standard kind like in the servo or transmitter, this has too much resistance to movement it requires far too much weight for reliable operation . The other is a specialist type used in position sensing, it moves freely with little weight but is far too big. It appears to work well other than that.
I was fairly sure that IOM’s would restrict this kind of system.
My origional thought was to use this system is for a Footy class boat (open rules except for the 2 channels for this application) and use the batterys as the movable ballast however as it stands now with what I have, it is too bulky to use in a Footy.

Nick -

I believe Claudio was meaning that the “Legs” of the course would need to be sufficiently long in order to maximize any benefit from a canting keel… example: if the leg is short, or you wind up in a tacking duel, the continual movement of a keel from one side to another would be a negative aspect, since you would need to continually be trimming your sails to match the heeling of the boat. Wiithout a crew (or deck hands) this “could” become problematic in that you spend more time trying to trim the boat and less time thinking tactics and boat speed.

For a long-distance (marathon) type of course, where a tack can be held for some time, the problem of trimming goes away.

In previous discussion, I too felt that NOT being on board the boat when it starts to heel was a big disadvantage, since on a big boat, one’s other senses can relate to minor heeling movements, whereas using vision only (and at 100 yards or more) becomes a matter - as you say - being a reactive movement - not an anticipated movement. On my big boat, I could feel the boat doing a lot of stuff under me … before it was visually noticed … heeling, lift and headers, puffs and more wind on mainsheet, lightning of main sheet during a gybe, etc.

Back in the days of Doug Lord’s participation here - he also felt a need to not only move side to side, but to (possibly) move for and aft as well. Of course this might only work with an above deck system on say, a multihull.

“Wind Warrior” boats from “down-under” are the only production boats that I know of, that use canting keels. It might be helpful if you do an internet search and correspond with the owner of the company to see what he has learned during the past several years building and selling canting keel monohulls. Good luck with the project.



Been a while since I posted.

I have played around with the idea of a moveable ballast and mine been a canting keel I buitl my orignal boat and the intial though was to have it do it automatically but after toying with it I opted for running a third channel.

I would say running a canting keel would be slightly different as to what is been proposed on here due to the fact from my understanding is that the moveable ballast would be the primary ballast and thus this would need to be trimmed correctly for it to stay even up right. On my canting keel boat it sails fine with the keel on the centre line but since the keel is lighter than normal it heels over more. So effectively if you have a good constant breeze and are sailing up wind with keel at full cant it is the same as any fixed keel boat sailing up wind with keel in the centre they both just lean over more in the gusts.

The one thing to understand about moveable ballast is it does change the trim of the boat quite a bit and not just in respects of heel but also the helm as the weight is out side the shear of the boat this is now where the boat wants to turn around not a point underneath the hull may sound odd but it does happen.

I am just in the throughs of Finishing boat number 2 built to the Formula 100 rule a bit different in concept to my first boat but still the same hull just diffrent appendages weight rig and about 1 kg lighter over all but due to a lighter hull components and rig. Just waiting for my sails to arrive and will be making a splash so will post some pics when I do.

Anyway my thoughts.

Cheers Blair

good to see you back.

mmm, the joys of canting keels/deck ballast, i am gonna be changing my boat very soon to a better setup, with everything (part from the keel/bulb) inside the boat & see how that goes, it is just sealing it that will be the problem but even then that aint that big a problem. still gonna be using automatic, am going with 2 canards at about the turn of the bulge on an angle like the volvo 70’s & open 60’s

I’m “reopening” this thread since I’m interested in, and starting a canting keel. Yes (per Dick Lemke) Wind Warrior (Ultimate Warrior) has one yet haven’t seen below decks. This sailor, noodle posted these videos which many of you may have seen…
Canting Keel
… the workings are extremely nice (NZ builders are good).

I’ve posted some mock-ups that I’m experimenting with…
#1 (cam version) that I’ve worked on a lot more, replacing foam in video with gears, but just can’t get it right (slips and takes up too much room in my narrow beamed yacht).
#2 goes back to “traditional lines” and uses a foam covered wheel to eliminate bungees. Not much time in this one yet.

I’d really like to see other concepts, what you builders are playing with in this regard. And advice.


Well Guys I have finally finsihed my canting keel boat number 2 and its sails great

I have some pics but the filea are to big to post if anyone is keen to see them let me know and I can e-mail them out.

The rotating wing mast works really good as well needs a little bit of fine tuning but it sails great and the guy that made the sails for me did an awesum job.


would love to see your boat! try


Me too, please:

My “Flintstone’s” version is operational yet not in boat, so it may not really count yet. Its here at YouTube. My keel has threaded rods embedded in top section, hence two holes on swing arm.

Text reads: “Rough yet functional. Oiled nylon rope with graphite through nylon guides. Narrow beam of sailboat means eliminating pulleys which take up space at end of canting swing.”

Thanks Gappy.

gappy, if you send me the pics, I can upload them on to my web site (since I got lots of room), then you can post a link for all to see.


I would be interested in seeing a picture of your wingmast rig. I will PM you with my email address.

… it is on a reach that the most dramatic bursts of speed are observed, regularly sailing around an entire race fleet. Upwind in light winds performance is marginally but consistently greater than the top boats.

Text about yacht Phie at
Back to canting keels… or CANTING RIGS, as seen here at The text indicates the Marblehead sails extremely well.

Has anyone taken this approach as well? Or possibly the designer of Phie is part of this forum, and can say more about how she sails compared to moving the lead.


This skipper came to me dumfounded over his inability to retain a decent crew. He worked tirelessly to improve his boat and keep current with the latest techniques and go-fast gear. having heard much about how canting-ballast technology has revolutionized bigger boats, he wondered if he could more effectively utilize his moveable ballast. I had to remind him that while some crews have affectionately given their canting bulbs nicknames like “Willy”, it doesn’t mean they have any desire to trade places with them. :stuck_out_tongue:

I’ve been thinking of making a Scow (I have a full sized MC Scow) with a counter balance. I think a gyro would work well… and it would probably work well with canting rigs as well. I would probably try a heading hold like the GY401.