My F100 CKTF Boat

And its happened again!! Another thread hijacked by the personal obsessions of one individual.

No longer about JohnB’s unique boat, this thread has become a forum on Doug Lord’s ideas about collective steering. Nothing new, just the same old rehash of Doug claiming huge breakthroughs for things he has never built nor sailed.

The shame is that the interesting work of someone who has actually built a very complicated boat has gotten lost.

Roy, Johns boat uses a twin foil system and will use collective sincethat is the only way to exploit theadvantages of twin foils. The post I made regarding balance and collective was an attempt to begin a dialogue between those of us that have built twin foil boats and are about to sail them. The information presented include nuggets of info from both Graham Bantock and Bruce Sutphen as well as the heretofore unknown two boat testing of two models one equipped with twin foils .
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Doug Lord
–High Technology Sailing/Racing

Sorry, doesn’t cut it. John B. didn’t say a single thing about collective steering, you brought it up and hijacked his thread.
And this isn’t just an isolated incident, its standard operating procedure.

Hey, John, please post again and let us know how the boat behaved in its initial trials.

And I’d like to try to bring this back to John’s boat and ask how many servos; how many battery packs, overall weight and total sail area with and without gennaker.

right on roy tell us more about your f100 johnb

Never hold your farts in.
They travel up your spine, into your brain,
and that’s where sh*+y ideas come from.


Perhaps my math was not clear enough for you. Let me see if I can make it more clear:

Assuming there is no wind in the sail and the ballast is canted fully to one side, then you are correct that the boat will heel to windward. If we further assume that the keel cants 55 degrees as seems to be a common number, then that would cause the mast and hull to heel 55 degrees to windward if there is no wind in the sails. But now the mass of the rig is acting to cause the boat to heel further than 55 degrees. How much further depends on a lot of factors, but the dominant tewrm in the equation is the righting moment of the keel versus the heeling moment of the rig mass. I’ll use my numbers from the US1M from here since I do not know the dimensions for the F100. If we assume that the CG of the rig is roughly 50% up the mast and we have a 60" tall mast, then that puts the CG of the rig 30" above the deck. The CG of the keel is 14 inches below the bottom of the hull. Lets say the deck is 5" above the bottom of the hull and lets further assume that the boat is heeling about a pivot point right at the bottom of the hull. Then the CG of the rig is 35 inches above the pivot point and the CG of the ballast is 14 inches below the pivot point. The righting moment of the keel is given by:

Keel Bulb Mass * Moment arm * sin (heel)

The heeling moment of the rig is given by

Rig Mass * Moment Arm * Sin (heel + 55 degrees)

How much does the Rig weigh? Lets assume about 8 oz (that’s pretty heavy, but a good starting point).

Lets further assume that we have a very light weight keel bulb mass of 2.5 lbs

Now we set the heeling and righting moments equal to each other and solve for the heel angle that brings the system to equilibrium:

Keel Bulb Mass (2.5 lb) * Moment arm (14") * sin (heel) = Rig Mass (0.5 lb) * Moment Arm (35") * Sin (heel + 55 degrees)

Equilibrium is achieved at at a heel of 29.86748 degrees leaving the sail still 5 degrees above the water.

If you increase the keel bulb mass to a more reasonable 3.5 lbs, equlibrium is achieved at a heel of 20 degrees which leaves the sail still 15 degrees above the water.

And is you applied a more realistic pivot point that took the prismatic coefficient of the hull into account, you would find that the equilibrium heel would be less than these numbers.

So, in order for the sail to land in the water, you would need to have less mass in your bulb than this and that would lead to a design that had an undesirably low amount of righting moment for normal fully powered sailing conditions…

But you do ask a really good question: “Why would you want to add a feature that must be babysat for every second of the race”. Hmmm, this is intriguing. In racing scows in light to moderate conditions, the crew must be constantly shifting their weight to keep the boat from overheeling. In heavy winds when the crew is fully hiked, the skipper needs to play the mainsheet and backstay controls to keep the boat from tipping over. In full sized multihulls (a boat type I know you have experience with) when the crew is fully out on the trapeze, the skipper needs to play the traveler to keep the boat from tipping over. what is the advantage? Why not add 1000 lbs of lead to the bottoms of these boats so that the crews can sit back and drink beers and not have to worry about the boat tipping over? The answer is because heavy keels are slow.

Yes, you need to “babysit” your canting keel position just like you need to “babysit” your crew weight on a dinghy. A lot of people don’t race dinghies because they don’t like to capsize. That is fine with me. but a lot of people do like to race dinghies because they are fast, responsive boats that require a certain level of sailing skill to sail well.

A canting keel boat falls in between a dinghy and a fixed keel boat in terms of performance potential and skill required to sail it.

  • Will

Will Gorgen

EDIT: In re-reading this post, I realize that I used my canting MAST equations. Thus the heel of the boat is used to calculate the righting moment of the keel and the heeling moment of the mass of the rig is the heel of the boat + the 55 degree rig cant. If you wanted to apply this to a canting keel boat, then you would think of heel as the angle of the keel strut to vertical rather than the heel of the boat (which would now be fixed to the mast. I apologize for any confusion this may have caused…

  • Will

Will -

thanks for the clarification, and I understand.

Let’s look at the difference however, and one that has been discussed many times with Doug, without resolution or response…

Using your dinghy/Scow or multihull as an example, versus an r/c boat - the point was that when “on board” you can “feel” what is happening as it does! This cannot be disputed. Standing on shore, even 15 feet from an r/c sailboat, no one can tell the heel that is “coming”, nor can they even tell it is happening until …a) there is a large amount of below the waterline hull showing, or …b) the boat suddenly heads up as the mainsail swings toward the water in a gust. On a real boat with feet or butts firmly planted, one can feel the weather rail going up and make necessary adjustments - further hiking, flatter on trap, mainsheet/traveller play, etc.

I have argued many times with Doug on the issue of Power Ballast theory, that it is always adjusted as a “reactive” measure. If we move that same illustrative r/c boat further out into the pond, and it takes even more heel to produce a visible recognition of what is happening. Further out, even less reliable and easily detected heeling movement.

We already know that many of our older members that race have difficulty seeing the distance for a rounding mark - often hitting, bumping or brushing it as the round takes place. Now Doug is suggesting that by adding a canting keel, that needs to be adjusted, it is a better way to race.

How does impaired (or not) eyesight allow one to determine keel cant from over 100 feet away on the race course? If by the angle of mast heel, this would be the same for a fixed keel boat too.

How do you know whether to cant to 55 degrees - or only 15 degrees when far from shore?

With a fixed keel and a wind gust, the skipper can merely rely on rudder and can watch boats around him - tack, drive off, feather up, etc. By adding a canting keel, you have just added that “babysitting” feature I referred to. We don’t have crew on board to raise/lower daggerboards. Windward rudders aren’t lifted downwind. We do ease backstay via a radio channel, but don’t release down haul or out haul on the main. Jib sheeting isn’t changed for upwind versus downwind sailing, and jibs aren’t backwinded when tacking a multihull.

So between not seeing “what” the position is, and not being on board to take advantage of “sensory” feel, the “one-armed paper hanger” scenario is probably possible.

There are just too many things that one does sailing a big boat, that are difficult to replicate on an r/c boat, and I guess my opinion is moving ballast, (when one isn’t close enough to see or feel) is one of those things.

Again, it is one of those “Gee Whizz” features, that while it can be done, I would question what benefit is gained. Eventually, if the idea sells itself to have a canting keel boat, collective steering, moveable deck ballast, everyone will have it - so you are pretty much back to a one design application. The much hyped Spinnaker equipped boats sail by themselves. Since they all have them as a one-design - what is the benefit - except one more thing to worry about.

Now if the concept of Canting Keel Formula 100 boats were to race in any kind of open event, and proved faster, soon handicapping would be introduced to remove that benefit - and we are back to the principle of KISS ! Unfortunately, in his zeal to promote this technology, Doug still avoids the basic question of where will they race and against whom? Like the F3 foiler - it works - but so what … $1500 or more to have something unique? No one to race against, questionable performance in light air. Same could be said for canting keels on monohulls… it works - but … then what?

Again, I am hesitant to try PBS on a multihull, as well as foils. Not because they don’t/won’t work, but the answers and experiences that I have aren’t addressed - legitimate concerns are brushed aside in an effort to promote something. Fine - but when one asks and it’s considered a personal attack is a completly different story. Please don’t follow Doug’s lead by stating “I simply don’t understand!” because I do - I just want to see it demonstrated to show it’s superiority. I think that is all any of us want - to SEE IT !


Two things regarding reacting to the heel of the boat:

  1. Hal Robinson’s canting mast boat uses a pendulum system to adjust the mast cant. As the boat heels, the mast will cant to keep the mast perpendicular to the water. Thus, the boat “feels” the heeling and adjusts. A similar system could be adapted for a canting keel boat if you wanted to repliact the feel of your crew in responding to boat heel with extra weight on the rail. Hal’s system had some problems associated with underdamped oscillations. He fixed that with a damper that slows down the response of the system. I think that a gyro would be a better solution.

  2. the heel of the boat is one of the easiest things to see from shore. The long pointer that sticks up in the air called a mast tells you instantly when the boat heels. Most sailors use their mast movement to determine when they are hit by a puff, when they are pinching, etc. Anyone who cannot read the heel of their boat is not going to be a very competitive sailor. When you see the boat heel, you push on the stick to add more cant. If the boat goes flat, you reduce cant. If the stick is near the middle, then your keel is canted only a small amount. If it is pushed way over to the side, then the keel is near/at full cant. Pretty simple. But, yes, it is a new function that must be mastered.

Here’s the rub. How simple of a boat you want is a matter of personal taste. If you want 2 channel control (rudder and sail) there are a multitude of classes to choose from. If you want to control a few more things, classes like the US1M and AC allow more channels. Many of the top AC sailors use 6 or 7 channels to control things like vangs, backstays, travelers, etc. but if you don’t want to control more that 2 things, then stick with the classes that limit you to 2 channels.

You are right that if any of these systems turns out to be beneficial, then either everyone will switch, or a handicapping system will cancel it out. So what? Why do you own a multihull? You want to go faster than a monohull, right? But if everyone owns multihulls then where is the advantage? The advantage is that they set a different standard for performance that must be mastered. Same is true of canting keels. If every boat in a given class has one then there is no advantage, but that class has a different standard of performance that you must measure up to if you want to compete.Why would someone bother to design a new US1M hull when the Mistral works just fine? Because they want to raise the bar…

Some people want more performance than traditional keelboats have to offer. Some of us choose to explore the potential of dinghy like performance with canting ballast systems while others choose to pursue multihulls. Lots of people are completely satisfied with their keelboat performance and have no desire to pursue anything else. Seems to me there is plenty of room on the pond for all of us…

  • Will

Will Gorgen

Sailing my ckt boat to windward in powered up conditions, say force 2-3, the keel goes right out to windward after a tack and stays out there untill the next tack, and the boat is sailed pretty much as a normal keelboat would be. Most of the keel tweaking is done in marginal conditions and offwind. Timing in the tack is also fairly critical, if you tack and leave the keel on the wrong side you will have the boat over 80degrees plus easily, and it can take a long time to get it back and sailing fast again. Broaching downwind is the biggest problem, but I have ideas on how to solve that one, just got to get some damn exams out of the way so I can have some free time again!

Luff 'em & leave 'em.

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by lorsail

Therein lies the fun of racing these types of boat<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>

Doug - as noted in my response to Will - let’s see it actually race before we once again label it as “fun”.

Will I understand the differences and concur with a few. As to why multihulls? Because it is a completely new and different boat - It isn’t a monohull with a lot of things to wiggle to get it to go fast. It is a class that has historic acceptance in more than just the state of florida, or the U.S. In fact, it is surprising that the U.S. is playing catch-up in the multihull class fields. With 30 Mini40’s and 20 2 Meter boats expected at next year’s French Championships, they certainly are well beyond the 2-6 canting keel boats about and seem to be a functioning class. Add in the multihull numbers in New Zealand and Australia, and the 8-10 here under construction, and I think there is a definite class interest - AND a place to race them if you want to travel. On the otherhand - still no news about the French F-100 Class lately, so my guess is that the 6 - 8 will sail as a regional one-design.

I certainly hope for the best for your efforts here in the States. Hate to see all that work rewarded with a class-less fleet. Then again, if an oddity and a gimmick, and not a true recognized class, that remains to be seen.

Again, as noted to Doug - will await some photos of U.S. boats, and then of U.S. boats racing ! Can always change my mind later - right?


OK, so you are saying that sailing multis is different from monos and that makes it interesting. And that is good.

Canting keels are different. sure they are not for everyone and they have not proven themselves in the RC world yet. But they are different. They add another dimension of sailing skill and potential for higher performance - much the same can be said about multihulls, right?

So the way I see it we are both looking for something new and different from the vanilla monos. The difference is that you went for multis and I am pursuing an avenue that will allow me to race in the US1M fleet here in town. But the basic motivation is the same.

Can we agree to agree on this one?

  • Will

Will Gorgen

Sure … but canting keels in a US1M fleet?

Rules get changed?

Don’t you remember my US1M with a canting mast?

The theory of a canting mast vesus a canting keel is basically the same. With a canting mast boat the hull heels with the keel to high heeling angles to produce righting moment. With a canting keel boat, only the keel swings, but the net result is almost the same. Both systems produce a large amount of righting moment without loosing the effectiveness of the sails. The only difference between the canting mast and the canting keel concept is how much the hull heels…

I’d rather use a canting keel, but as you pointed out the US1M rules do not allow it.

The US1M rules do not allow a forward rudder, so I cannot have a CMTF (can I say that without a TM symbol?) configuration. The best things that the rules allow is to put wings on the keel so that when the boat is heeled excessively, those wings will be nearly vertical and therefore produce some lateral resistance. I am using Doug’s kFoil system so that I can switch the wings “on” and “off” to experiment with whether the extra drag of the extra wetted surface area hurts me more than the extra lateral resistance helps. Jim Linville has ruled that this system constitutes movable ballast and has therefore ruled it illegal. If the results of my experimentation show that the wings help, then I will build a bulb with fixed wings. If the experiments show that the wings hurt, then I will build a bare bulb. If the results of the experiements show that the wings help in some conditions and hur in others (this is what I am expecting to find) then I will build two bulbs - one with wings and one without for different condtitions…

  • Will

Will Gorgen

Ok - yes I recall - but thought I had missed the “memo” for some reason. Didn’t connect the two. Sorry !


So when you going to get this boat out there and sailing? I’m really looking forward to hearing about your maiden voyage. Hope it goes as good as it looks! Really wonderful work here. PLEASE, keep up posted. Since you are really the only one out there that seems to be really coming through on this, it would be great if you keep in touch with your updates. Photos sailing are of course always great to look over.

Keep up the great work,


I have been posting about my boat but have yet to get any pics as I did not have access to a digital camera but now do and will get some pics of both my sailing F100 and my new one under construction onto here as soon as i get back to NZ bas I am currently in the states for work and have not been able to work on my boat so unable to get any pics on the board at the momnet but only a couple more weeks to go before I get back.

Cheers Gappy

Gappy, didn’t mean to exclude you here, sorry. I gather your on boat #2 now? What did you learn from boat #1 if that’s the case.

Where in the states are you now? If your anywhere near CT in the northeast then you should come visit our club. I’ll get ya a nice boat to sail. Also the IOM nationals are on the weekend of the 19th. Looks to be the biggest national regatta around the US.

no greg, he would be boat #3. you are forgetting that matt lingley beat all of us ck wannabes to the punch and put the first (for this site) ck on the water.




Thanks for that I am in CT in Guilford at Navtec working on some superyacht rigging and hydraulics for some boats we are doing in NZ.

I put my first boat in the water about late november last year and is the same hull sahpe as boat to but boat two will be about 1.2kgs light overall when sailing but have the same amount of lead so it should be a bit quicker and things learnt from the first boat have gone into this.

The canting keel boats can be a bit hard to sail when starting out and the balance of my boat was wrong to start out with but soon fixed that it it sailed itself upwind with keel max canted and just trucking along. You can carry alot more sail area up wind but when you turn the corner it can be all on and trying to stay in control can be the problem to stop nose diving so i have found that the keel bulb needs to be slightly further back than normal which stops the bow driving under when going up wind but helps it down wind also. The trim when statioanry does not really look great but sailing it looks great so Iam happy with where I ended up. I do not have collective steering like Doug raves about as I believe you have enough on with 4 channels up wind than playing with that as well and keeping an eye on the course. My fourth channel is an adjustable backstay to depower in the gusts.

Any way must get back to work. Sure is warm here in the States at the moment.

Cheers Gappy


Sent you an email. Get back to me.



Unfortunatley I am not on my standard e-mail as I cannot access it and my auto forward is not working.

E-mail me on my other address which I can get to

Cheers Gappy