CBTF (Canting Boat Twin Foils) . . . Class legal.

First of all, I am not actually working on what I am about to say, and am just a jerk that likes to argue the rules but please read below and reflect for a minute before responding.

If I take a model CBTF boat, with the mast and running rig on, and place it in the water on a day with no wind, and “move” the keel from side to side . . . what happens? Does the keel move back and forth while the boat stays verticle?!?!? no, the keel stays stationary in the water, staying in place and in a vertical column. Therefore, I propose I rename the CBTF technolog to Canting Boat Twin Foil. It is the hull and rig that move around the keel, and not the other way around. Therefore, I do not actually have moveable ballast and the boat fits into many existing class rules within the AMYA.

CBTF would be class legal, however moving a Power Ballast System on deck would still be illegal.



PS: I am indeed somewhat joking, but as a closet designer, I love to find loopholes within existing rules to exploit. If a rule dissalows moveable ballast without staing a refernce point to hold stationary it is hard to tell what is and is not legal (canting rig with a canting rudder and canting second foil might be legal within the USOM class however CBTF is not?!?!? Where is the line really?!?!?

OH Brother! If I were you I wouldn’t try that unless you want to be drawn and quarterd and have your DNA removed!
From a logical standpoint you would have trouble because all rules regarding movable ballast have as their premise a sailboat. A sailboat UNDER SAIL would definitely be moving the ballast to keep the rig vertical. On the other hand Hal Robinson and soon Will Gorgen will be doing a little rule exploiting themselves(maybe Hal already has) by canting the mast. But under sail the mast stays near vertical most of the time so what cants? The hull with a fixed keel does creating righting moment.So a canting mast boat is essentially a canting keel boat after all!
The intricasies must come done to anything that moves relative to the hull: if you hold the hull the canting keel moves and is illegal; if you hold the hul still and move the canting mast the hull with its fixed ballast doesn’t move and is legal.
So I guess the anti movable ballast rule should read: “movable ballast is illegal. If the ballast moves while the hull is held still then it is movable ballast.”
Just build an F100 with CBTF and beat the hell out of the boats from the last two centuries and that will be that.

Doug Lord
–High Technology Sailing/Racing

Yes I know. . . Drawn and quartered. I realize it would never fly on the water, but an interesting thought none the less.

I Know hal robinson, and have done some work with him recently. I have seen his canting rig boat and have heard that it has been on the water(though I have never actually seen it sail). Its fun to work with the likes of Hal as he like I enjoys looking for innovation that fits with in existing rules. The canting rig has been deemed legal by the powers that be within the US one meter class which has made me wonder what else is legal.


tb i agree with your statement. but do not believe that you should be drawn and quatered. with us backwrads designer. you sometime get the piont. moving ballast is just another way of moving keel pos., I would rather move the keel ballast back that side to side. just think on the down wind leg you could have all the wieght at the back of the hull. and keep the bow out of the water. this would keep the boat level. and get a andvantage over the boat with the bow in the water. dont call yourself a jerk. you design boats. I do to. and many people have called my sedigns “garbage”. but i can piont out to them that . this boat is mine. not a beb stern boat or a graham bantcok boat. this is a lloyd G. Ertel boat, design a fast boat is hard. and if you desing one . take pride in that. i have not heard of the canting rig. but it sounds intresting

I was at a college laser regatta at yale once and there was no wind. So just for the hell of it, a few of us decided to race around the bouys ignoring the kinetics rules. We stood on the foredecks of our boats, grabbed the mast with both hands and lean from side to side as hard and fast as you can. You need to cleat the sail off and tie off the tiller so that it cannot swing to far. If you do it right, you can get going really quite fast. One guy claimed he was planing but he was full of crap.

So the bottom line is that in no wind situations, you could get a lot of boatspeed from wiggling your keel back and forth as you describe.

But getting back to the US1M rules. I think they disallow a rudder in front of the keel and allow no other appendages like centerboards, bilgeboards, etc. So I think the extra appendage is out. Or have I misread the rules?

I hope to have a canting mast US1M boat on the water this summer as well. The hull is in my basement. I’ve begun work on the mast bulkhead and some of the other interior structure. I need to buy a mast and sails soon. Any suggestions?

  • Will

Will Gorgen

Ya know, im friends with hal, and I know that it has been deemed legal, but the thing that I find uncomfortable, is that a canting mast, is really a rotating mast and therefore illegal according to the rule. . . sure it is not rotating about its verticle axis, but it definately is rotating about the lengthwise axis of the boat. annnnnnnnnnnnnny how.

USOM rule: (Prohibited)
8.1 Moveable keels, shifting ballast, bilgeboards, tunnel hull, trim tabs, rotating mast, wing sails.

so on the canting rig, No bilgeboards. . . .but what is the definition of a bilge board? I dont believe that a fixed (non-retractable forward foil) would count as a bilgeboard . . . would it?!?!?! I believe that by definition a bilge board, like a center board is a rotationaly retractable foild used to prevent leeway. A bilge board is not found on the centerline, rather one coming out of both the port and starbord bilge as used on a scow.

Am I wrong?!?!?

TB, I don’t think a daggerboard could seriously be defined as a “bilge board”. So it would seem there is a good case for a daggerboard with a canting mast in the US One Meter Class. I don’t know how questions like that are"officially" resolved; I guess a start would be to discuss it with Jim.
But, your next problem is how to install the daggerboard so that it cants side to side so that as the boat heels the rudder and daggerboard stay roughly parallel to the mast. Ideally, it should be retractable for lite air and downwind to take full advantage of the daggerboard. But then a serious design concern would be the change in balance that would occur as the boat heels with a fixed daggerboard. IF the daggeboard were in front of the keel then as the keel was unloaded the CLR would shift forward which,since the keel is only unloaded in heavy air, would be a bad thing resulting in an increase of weather helm. Putting the daggerboard aft of the keel would be a better solution because then the shift of the CLR and sail CE would match and there would be no potential balance problem.
Also seems that THEORETICALLY you could have two rotating foils-only half of each a rudder-technically one rudder(HA) and the other half of each lateral resistance. If you could make the forward foil stay parallel to the aft foil as the boat heeled you’d have a canting mast version of CBTF…The clear advantage to this would be collective steering which would eliminate leeway induced drag on the hull, fin and bulb allowing faster speed upwind. You could then make the fin the absolute minimum chord possible consistent with a thin 6-7% t/c ratio since it would no longer be required for upwind lateral resistance…
But something tells me that none of this would be allowed…

Doug Lord
–High Technology Sailing/Racing

Ill just quote jim linville from our conversation just the other day.

“Dog gone it, this rule has been around unchanged since 1980. . . now you come along and within one year you find two substantial loopholes that I am going to have to close up.”

Translation. . . you could definately throw a third foil on there right now (it might not be able to be a rudder but could be a daggerboard, and even retractable) and be class legal, but enjoy it for the season, the rule will most likely be changed.

The way to deal with questions like this is to write a question to Jim and have him circulate it to the technical comittee who will rule wether or not it is legal based on the current rule as it is written. They were very fair and honest with one of my rules questions.


So Jim felt that you could put a canting foil in front of the keel and it would be legal?

I alwas assumed that it would either be considered a (second) canting keel which is illegal under rule 8.1 or it would have to be considered a rudder which needs to be aft of the keel by rule 6.1. What is the definition of a daggerboard? Does it have to go up and down through a slot to be considered a daggerboard?

According to the Equipment Rules of Sailing (ERS) a daggerboard is “A retractable hull appendage attached approximately on the hull centerplane and not rotating, primarily used to affect leeway”. so in order for it to be a daggerboard it would need to retract.

The ERS does not have any appendage types that are specifically allowed to cant. So whatever it is it would be a canting version of it.

I think in order for it to be a canting daggerboard, it would also need to retract.

There is another appendage defined in the ERS - a Fin: “A fixed hull appendage primarily used to affect leeway or control”. So maybe it would be a canting fin?

Is Jim back from his vacation? I need to talk to him about some Model Yachting stuff…

  • Will

Will Gorgen

First of all, I have been told by some that though the AMYA have adopted the ISAF sailing rules, however NOT the ERS. So any term in the ERS is fairly worthless other than to site it as reference.

So on to rule 8.1:

USOM rule: (Prohibited)
8.1 Moveable keels, shifting ballast, bilgeboards, tunnel hull, trim tabs, rotating mast, wing sails.

  1. a Keel would have ballast in it
  2. shifting ballast, there is no ballast on the proposed fin
  3. a bilgeboard is a board that comes out at an angle from the side bilge of a boat (think scow)
  4. tunnel hull . . . nope
  5. A trim tab is onthe leading or trailing edge of a foil.
    6 and 7) have to do with rigging.

so I dont think it matters what you call it. You most likely DONT want it to be a rudder becaose there is a clear point where it is stated that the (non plural) rudder(once again non plural) must be behind the keel. Based on that, you might not be able to have a second rudder. So, this does not keep you from having a daggerboard, or centerboard, or even a fixed “skeg” of somekind infront of or behind the keel strut.

Personally, I think the way to do it is to have your canting mast servo also drive the up down position of a canting daggerboard. When the mast is verticle, the fin is retracted. As the mast is canted in either direction, the foil proportionaly extends the right amount to provide the correct amount of lateral resistance.

Jim is home now, and you could ask him directly along with your other questions.


Nice try Todd, but…

Where is a “keel” defined as having “ballast”? In fact the prohibition of no moving keels is seperate from the prohibiton on shifting ballast, clearly they are not one and the same. Further, based on your kind of strict reading of the rules since a fin has some mass/weight it does, in fact, have “ballast” in it. (Heck, based on your literal reading a “tunnel hydoplane” would be perfectly legal since we all know a “tunnel” is something that runs under Boston Harbor <lol>). Bottom line is you can’t move “fins” or “keels” in a US1M up and down, back and forth or side to side.

I know its cold up in Mass. but maybe you have a little too much time on your hands. Think about coming down to Connecticut and frostbiting IOM’s some weekend.

Todd, I agree that I think you are getting cabin fever! (LOL) As I certainly am!
I don’t see a great chance of success to get this through, but, we are talking about a class secretary that hates to discourage thinkers like yourself, so there is always a possibility you could talk your way through this. I for one would love to see you develop such a boat, but would also hate to see it become a class legal thing to do. One of the best parts about the US1M is its simplicity I think. If your boat was legal and proved to be dominant, it would certainly drive a nail in the soon to come coffin for the US1M class. It?s hard enough for this class to get newcomers that are willing to build boats as there are, and it?s proven that a home built boat is quite competitive. I see this as possibly sending more skippers away from the US1M and into the IOM class.
As to you building such a boat, as I said It would be great. It would be very interesting to see if something like this would advance performance. Adding a third appendage? This would make a good experiment as to induced drag over any type of performance gain. I for one would be surprised if you could make a boat like this that would gain over the conventional US1M design if in fact it was even be able to keep up. If you are successful, you might be opening the door to the twin foil, canting keel designs success possibilities. It would be interesting if someone like yourself finally would actually do something like this rather then speculate over it?s great success or failure.
I say go for it for experimental reasons alone. But if you want it to be class legal, I would be the first to object.

Roy and Greg,
I will be the first to admit that I have cabin fever! Without a doubt. I have a couple snowboarding trips comming up and just got the ice rink shoveled off the other day, so it should clear up some of the cabin fever symptoms!

First of all, As I stated in my first post in the thread, I am currently NOT planning on builing anyting like this. I just find the whole moveable ballast concept in these rules interesting as without a specific reference as stationary, even a lead belly has moveable ballast. . .

One thing I find interesting about a small loophole I did find, is that without a doubt, next year, it will be sewn up. Its a developmental class, yet as soon as you find a hole, it will be taken away. I truly understand it is whats best for the class, but its kind of disheartening. “Go ahead and experiment . . . but if you start winning, were going to vote it out of existance to keep the class alive.”

Now I agree that the one hole I did find (hasnt been mentioned here)opens the door for WAY too much liberty that I wouldnt even want to deal with. . . I have been told by Jim that it is indeed a hole, and go ahead and use it for the season if I wish, but next year it will be illegal. . . so, why will I waste my time and effort with my idea to only be able to use it for one season?!?! Similarily, Canting Mast Twin Foil. . . if and when Hal and Will get their boats working . . it probably will be voted illegal by the class membership. But, I have pointed out to hal that there MAY be a way to add another foil and really make his boat move! (or the thing could end up being a DOG! who knows!)

In all reality Greg and Roy, I am a Keep it Simple Stupid kind of guy. Greg, you have seen my boat. No Bells, no Whistles, no extra parts, no nothing, and trust me . . if I ever get it built, my new boat will be just about as simple.

As I have already been told by jim that this loophole will be sewn up, I can share the following with you:


it looks blank, but the first page is a cover sheet, scroll down. Basically, it says that there is a way in the rule that would allow a someone to put a stern mounted overhanging rudder on a boat that is already 39.375" long and have it be class legal currently. Sure, I know there are downsides, but I have found some theoretical gains in what it would allow for. The problem, if it is indeed true thatI could put a rudder off the back end of my boat, then one could actually put a Hula type appendage mounted off the back of the boat that was as long as they wanted. You could make a US one meter that was actually longer than a marblehead! The conclusion was that part of the Tech Committee thinks its a valid loophole. The other part thinks it goes against the spirit of the rule, all parties involved think its a hole that should be closed.

Going snowboarding tonight . . .cabin feaver should deminish!


Well, despite Todd’s insistance that a forward fin, foil, anything-but-a-rudder-appendage, whatever is legal, I will continue to build my boat without one. I am going to stay within what are the currently understood rules: that a canting mast is legal, and wings on the keel are legal. This was the design direction I chose when I started, and I intend to carry through with it.

The hull is sitting in my basement (generously donated by a local sailor). I have begun laying up some bulkheads. The mast is on order and should arrive soon. I have the airfoils for the wings on the keel. Things are moving forward!

As far as the US1M class is concerned, I have never considered this class to be simple. It is in fact inherent that in a rule that restricts very few things, there are a lot more degrees of freedom to play with. A simple example is the sail. The “measured area” is 600 square inches, right, but because of the unmeasured roaches and the degree of latitude that you have in foot lengths, and luff length for the jib, you can get as much as 850 square inches of sail area. I’m not sure how much variation in sail area there is in the class, but it may be quite a bit. The fact that you can have up to 4 channels of control is another nonsimple area of the rules. Hull shape is very unrestricted leading to lots of different possible hull shapes. And so on. The US1M class is designed to encourage experimentation. As such, it was never designed (in my opinion) to appeal to newcomers or even experienced sailors. It is a builders class which appeals to builders, tinkerers, experimenters, etc.

I intend to race my US1M boat against the US1Ms in our club (2 or 3 mors days, up to 9 on a good day). All of those boats are “Mistrals” which is a relatively old design. The guys in our club have been racing for a long time and have fine tuned their boats really well. so they will be tough to beat the first time on the water. But after some tuning, I hope to see what sort of advantage i can get from this canting mast technology.

Gotta wait for the ice to melt first…

  • Will

Will Gorgen

Greg, et al:

This is off topic, but in response to a comment made in this thread.

Are we wasting our time trying to breathe life into the USOM class? This is the development class with the easiest rules around. It was designed to be simple. I have been blamed for doing a lot of things that may have affected the health of the class, but what I did was within the rules of the class.

Want to make it simpler, or cheaper, or easier, change the rules. Make a proposal, put it to a vote. For example, propose that hulls can only be made of wood or fiberglass. Other than cost, my CF USOM isn’t any lighter than its balsa planked prototype.

I gave almost two decades (and a marriage) to this class; I am not ready to “call the code”!

Greg: since you are predicting the death of the USOM, want to sell your ORCO now before it is a relic? I’ll buy it.

Hey Steve,

I?m not sure what you are saying here. I certainly am not predicting the death of the US1M class at all. As a matter of fact I am see a recent growth and interest in it. 

But anyway, I still don?t know if I fully understand your post.
And NO, I will never sell the beloved ORCO! [^]


This is the quote to which I refer:

“If your boat was legal and proved to be dominant, it would certainly drive a nail in the soon to come coffin for the US1M class.”

Sounds to me like someone thinks the grim reaper is around the corner, regardless of the appearance of a dominant multifoil (more than rudder and keel/centerboard)USOM or any other innovation that is deemed legal under the present rules. Hopefully, “The reports of (its) death are greatly exaggerated” (MT, aka SC).

“It?s hard enough for this class to get newcomers that are willing to build boats as there are, and it?s proven that a home built boat is quite competitive. I see this as possibly sending more skippers away from the US1M and into the IOM class.”

Assuming the “this” is the interpretation of loosely defined rules that permit boats with multiple foils or other innovations to be legal in the USOM class. These items might be interpreted to be within the rules, but not the intentions of the framers of the rules. (According to one of the framers of the rules, the founding fathers were a little fuzzy around the edges the night the original Olympic One Meter was proposed, so a lot of dots and crosses were probably left off the rules.)

My other point referred to the early and mid 90’s when some boats were being made of kevlar and cf. These materials allowed boats to be lighter and strong, but they were more expensive than the majority of homebuilts from balsa. As USOM secretary, I took heat for permitting this to happen and building that way myself, but within what the class allowed. Then and now, if folks want to clarify, define, or change the rules, legislate through the COA. It doesn’t take a ballot issue of MY to hold a class vote. The class is a democracy, not a republic. No PAC’s, no backroom deals, no hanging chads (punus intendus). If the majority of voting owners legislate changes in an attempt to save the class, and it is not working, then a another solution can be proposed and voted upon. Like “The Great Experiment”, the class is a process, not a product. It is a dynamic, not static, environment. (Hey, the COA could have its own version of legislative analysts that could report on the impact that certain changes would make to the class. Yes, I do live too close to DC and I have worked on The Hill, when LBJ was pulling strings and beagle ears.)

I will have to agree with greg here. Locally, the US one meter class is doing quite well. Sure it might only be true in new england, or maybe just my back yard, but there is quite a refreshing amount of new work being done. I know of atleast 3-5 brand new hull designs that will be on the water early this upcomming season, some foil studies being done on existing and new foils, not to mention a decent amount of innovation and looking at different approaches to the rule. At our club, there should be 6 brand new US one meters on the water that should all be pretty darn fast(3-4 cobras, a variant, a Hal Potts design or 2 (which looks darn good), a TUS2 and hopefully one or two of my boats). I dont think the class is dying at all, but that just based on the local growth.
I think Greg’s only point is that allowing too much liberty with the rule, might actually open up too much of a hole that would be unhealthy for the class. If a major breakthrough were to occur that required a boat to carry 2 sail winches to be competative, you just effectively doubled the cost of some of these boats, and at that point, most people would start to look elsehwere. Part of the draw of the US one meter is that a used boat complete and competative can be bought for about $300. A boat can be built from scratch and put on the water for about $300 (hopefully competative) . . . if we add something like a canting technology and it is a substantial gain (which I dont think it is) everyone would have to buy new boats that were atleast the cost of a sail winch more expensive. To give you an idea, my last boat cost me $50 (made out of CF) to get on the water less sails and electronics.

I think there will always be a small niche for the US one meter. . . for people who want to design build and race boats that are competative in a class while only using a 2 channel radio, the US onemeter is it. Sure, the IOM might have better racing, but the rule is also more restrictive and currently not my cup of tea.

just my 2 cents. And though this has gone incredibly off topic, I think it is worth while conversation.


Two full size classes the I14 and the Moth are wrestling with the issue of cost containment or innovation. The cost containment guys say the innovation will kill the class.
The 14 er’s had just(more or less) gone thru an “amalgamation” that cost some a lot of money ; that and other reasons(killing the class was one) caused them to vote full flying foilers out.
Some in the Moth Class where foils are legal were startled by the performance at the Worlds in France by Rohan Veal so started campaign to “save” the class from runaway innovation. After Rohan won the Aussie Nationals in 8 straight races on foils with margins up to 9 minutes the class overwhelmingly voted to leave foils legal.
Two different classes , two different approaches.
I think that it is unfortunate that some development in the Us One Meter Class seems to be stifled by the mere mention that it will be voted out-luckily other guys are willing to proceed regardless. It also seems that a “development class” should bend over backwards to foster development --not restrict or ban breakthru’s or even potential breakthru’s…

Doug Lord
–High Technology Sailing/Racing

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

Two full size classes the I14 and the Moth are wrestling with the issue of cost …
… I think that it is unfortunate that some development in the Us One Meter Class seems to be stifled by the mere mention that it will be voted out-luckily other guys are willing to proceed regardless. It also seems that a “development class” should bend over backwards to foster development not restrict or ban breakthru’s or even potential breakthru’s…

Doug Lord
–High Technology Sailing/Racing
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
So, Doug, being that you know so much about what is going on in the US1M class, just how do you come to the conclusion that ??seems to be stifled by the mere mention that it will be voted out-luckily other guys are willing to proceed regardless?

I?m waiting?

Oh, you mean you are not involved with the class? You are not racing in the class?

Well, maybe that?s why you have no clue what you are talking about. Maybe you could enlighten us on just what experiments are being done with US1Ms that are class legal? Do you know about the rotating rig that is a possible class legal ?swing rig??
The US1M class secretary is very conscientious of promoting the thinking and developing of new ideas that can squeeze through any gaps of the US1M class rules. I have never heard anyone in the US1M class tell someone ?not to go for it?.
The only thing that you are constantly promoting here Doug is for these classes to change there rules to what ?you? consider to be new tech. I said it once here before that designing good hulls and appendages are the highest tech of all. It seems that in your eyes that its more like strapping a turbocharger onto a Pinto.
I can tell you, Jim has no intentions of playing around with such a successful class by re-writing the class rules

Todd can tell you that there is a whole lot of design discussions in the US1M class. And this is part of the challenge, to come up with new ideas that are within the rules, or the gaps in the rules. Your thinking seems to be continually in that the rules should change so that your money making ?s will be allowed. Just stick with the F100 Doug. Why the need to try and stick it to all of these classes that you are not at all involved in. Where is your US1M hull?