Why your gooseneck makes you nosedive?

Footies generally have non-rotating masts with essentially conventional goosenecks.

This means that the maximum angle of the boom to the centreline is around 90 degree, so that with the wind dead aft the sails are stalled plates.

Everything else being equal, a stalled plate will shed air in a direction at right angles to the nearest edge. This generates a resultant force in the opposite direction. Because the longest side of the sail is the leech and because the mast will to some extent act as a fence, the predominant force will be to windward and downwards.

The lower the rig aspect ratio (i.e. the shorter and fatter the sail), the bigger the downward component (in other words, the leech is closer to horizontal than it would be with a taller, narrower rig).

Since in the dead run condition the centre of effort is usually well forward of the centre of flotation, the effect of this downforce is to depress the bow.

I am far from sure how big this effect is - I cannot find any figures for the drag coefficient of a stalled plate the size of a Footy sail that look credible - but it may be significant.

Even if it is not significant per se, there are substantial advantages in letting the boom go forward of the centreline - look at any competitive Laser, Finn , OK or similar. The main remains a properly functioning aerofoil, produciong much more drive, exhibiting lower rolling tendencies, etc.

To do this? Rotating mast? Firefly dinghies used to arrange it very simply with a wire strop at the hounds on which there ran a sheave carrying the forestay. Or a gosseneck in the nature of a captive mast hoop - which might improve the geometry of the main luff as well? Another possible solution to the stalled downforce problem is to use a full-length top batten to produce a quadrilateral mainsail. This should bring the leech more vertical and hence reduce the downward component. See the Bantam and Bug designs.

Any comments?


Well it is nice that someone is paying attention to the details. My Bantam does carry a quadrilateral mainsail. The design justification is to eliminate drag in the upper triangular section of the mainsail (the part that contributes to heeling and nose-diving, but not to lift), vis-a-vis windsurfers. I do not use a full length batten aloft though, just sticky-back dacron that I use for the tablings elsewhere on the sails. Most of the plastic “sailcloths” that are available hold their airfoil shape well without the need for battens at a Footy’s dimensions. Also, full length battens don’t always “pop” to the other tack in light winds so I don’t recommend them.
I have found that the Bantams perform better with a lot of twist in the sails, and for my all out downwind setting I do let the sails out beyond 90 degrees. This is possible because I do not use sidestays and I have a “gooseneck” fitting that uses the mast as its pivot. I suppose that would be Angus’ “captive mast loop”. I’ve been using this system for three years now and I’m very happy with it.
In practice I’ve found that the theories that Angus mentioned above and that I’ve tried to work through do not improve the nose down attitude that is associated with running these boats downwind all that much. There is so little boat ahead of the mast, and the downward pressure so out of scale for its size, that I now think that boat design for this class will move in the direction of “going with the flow”. That is creating designs that utilize a non-horizontal downwind trim efficiently. How this concept will evolve (if at all) might make for some interesting craft. There would be some intriguing conflicts to resolve regarding shifting of the centers of bouyancy and lateral resistance, the configuration of, and angle of attack of the lead counterweight, as well as sail handling issues.
The fascinating aspect of the Footy is that it won’t conform to what we already know about r/c sailboats. It seems to pose some really tough challenges to get it to behave well. I think that down the road the most effective boats will not look like the other model yachts that the Box rule is trying to impose on this class. I hope the rule will evolve to embrace advancements and not act to suppress them, as is the case with so many of the other model yacht classes.

At last someone has come back with at least an ‘order of magnitude’ answer to one of my questions.

Thanks Neil.

As to ‘goinf with the flow’, I agree totally. Nose down trim is inevitable. We have to (a) reduce it and (b) make it work - if not for us - at least as little against us as possible. I would be very interested to see the lines plan of a Bantam - all I hace is the two photos on the Footy website. I’ll swap them for our current lines plans abuilding.

I also agree with the last point. If a Footy has a future other than is something amusing in the swimming pool - and we don’t have many of those here in northern England - it is as a mean technical machine. Forget the fact hat a cheeky, chirpy sheerline is easy with a 2-panel hard chine hull.


Angus, the powers that be have made Bantam an outlaw. My three hulls are grandfathered because I made them and registered them before the new box rule was enacted. Thus my design is a dead line of inquiry until changes are made in the rule.
Bantam has an “extreme” deck beam of 7-1/2". It won’t fit in the box. I had suggested the rule stipulate monohulls and that the long sides of the box be lowered to six inches, and that boats should be aligned along the centerline of the box. This would make Bantam and boats like her legal and, without the upper corners of the box, keep diagonally placed boats out of the equation. These ideas were nixed on the monohull definition which I was told was too complicated. It exists in other classes and could be included in the Footy rules as an appendix. But no, the arbiters like to put it in a box and lock it up.
I had hoped that the Footy rule would resemble the American 36/600 Class which I participate in. Our 36 rules produce some of the fastest, most innovative sailboats in the world for their size. 36 inches long, six hundred square inches of measured sail (just under 800 with the free roaches) with a 76" main hoist, displacement between 5 and 6 pounds. Mine sport swing rigs. The rules are a paragraph long. The following is small but the racing is very competitive.
The only other class that I know of that uses a box rule is the 36R in the UK. Thats “R” as in restricted. Photos that I’ve seen of these boats are uninspiring. And this is the what the arbiters of the rule want the Footy to resemble.
Now I consider myself part of the loyal opposition. I would like the rules to change to reflect the 12 inch length restriction as the primary and many of the other restrictions to be rethought, particularly since we know so little about this new breed of boat.
I do understand the arbiter’s inclination to keep the rules simple to encourage new blood into model yachting and to empower homebuilders. These are noble ends. I just don’t agree with their method or their box.
For example, restricting the Footy two two rigs won’t keep top level competitors from bringing more rigs with them and selecting which one to use at a regatta. The 12" Storm rig is pretty much useless in my view. The rig restriction does not level the playing field for the club level sailor as it was supposed to. Most of the IOM sailors in my club have only one suit of sails, because they don’t sail anywhere else. The same is pretty much the same for all the local club sailors that I know. Only those with regional, National or International ambitions carry a quiver of sails.
The AA battery restriction is short sighted because these cells are going to be phased out in the near future. Rechargeable ones are no longer available from retail outlets like Radio Shack of Circuit City here in NYC and the use of alkaline cells for r/c purposes is environmentally unconscionable. The rule should specify voltage not cell type.
I could go on like this for a while, but I think it would be more helpful to gather these comments for a separate thread in the future.

I got involved in these things after the box rule happened so I have far less of an axe to grind. Any class has to have some limitatations and it is good if it type forms to some extent - otherwise we get racing as ridiculous as Connor’s Cat v. the NZ K-boat. The box sets some limits. I am not totally convinced it does it very well. While we are all pissing at the end of the pond and can ask Brett for a definitive opinion it works quite well as a piece of brutal commonsense. If racing ever gets seriously keen in the future, God help us: there are a host of terms undefined and huge scope for pushing things (or trying to push them) that little bit further.

I do think it is very important that Brett’s interpretations, if he is effectively the technical committe of the Class Association - such as it is - should be recorded and made pwrmanently available online.

Back to Bantams - I’m aware that they are grandfathered, but they represent a very interesting approach. Sight of the linesplans would be most welcome.


Incidentally (and for example), it’s not a 12" storm rig: it’s a rig that projects 12" above the top of the box. It woould appear that with a non-max draft boat that is a completely different number.


Great discussion. It’s these type of talks where I sit back and learn, thanks.

A few comments regarding the Bantam, have you tried putting it in the box at an angle? You might need to rework where the rudder goes but give it a try. If the hull performs well it would be worth finding a way to stuff it in the box. Maybe set the rudder up so it can turn past 90 so it doesn’t have to use the slot. It would still be sailing trim since you could use the rudder as a brake for emergency prevention of starting fouls. :slight_smile:

Another idea that I have involves using the batteries to counteract nosediving. I’m thinking of putting them on a cradle that will slide back as the servo arm lets the sails out. Or are the batteries defined as ballast? If that’s the case how heavy can the servo arm be before it’s classed as ballast? It moves relative to the hull and is not massless. The way to find the true extent of the rules is to push them. (and I’m a low tech home builder)

Happy sailing…tallastro

Angus, I’ve been testing a rig on my American Footy that permits the sails to go well beyond 90 degrees. So far, I don’t see much advantage. I’m guessing the improvements to the nose diving will come from what we learn in the area of foils, bulbs, and perhaps the development of tunnel-hull designs or some innovation we haven’t thought of yet. And by the way, the latest versions of Razor and Am Footy I’ve been working with are seriously keen racing machines that will become even more so as I learn. It would be a mistake to think that because Razor is a chine design made from balsa that it can’t be a serious competitor.

John, I think about the only way Niel’s boat could fit in the box would be to drastically shorten the fin, get rid of the stern-mounted rudder, and try to put it in semi-sideways…it’s just too wide. Batteries are considered ballast, so the sliding idea is out…we need to get more creative to find a solution.

Niel, I wish you could see the opportunities in the box rule. It offers much more leeway in the Footy class than in the 36R class that you like to compare it to because of the box proportions. And more opportunity than the originally proposed rules. The diagonal issue allowing longer than 12 inches is pretty much a moot point, as long as we keep the AA battery rule…the weight distribution challenge seems to encourage beamier designs than a diagonal design allows. By the way, try WalMart or Home Depot for rechargeable AA’s…there’s plenty available in New Hampshire.
I know you have a long history with 36/600 class, but why should Footys be just another version of M or 36/600 only smaller? You said yourself that the 36/600 class only has a small following. Maybe you just wanted a rule where you could build a 36/600 with shorter spacing between stations to use your old designs? We’ve hardly begun to explore the possibilities of the rule. Of course serious racers will have multiple rigs. The rule was never intended to prevent that. It was intended, however, that restricting the rigs available for a race would make the choice a challenging one at the start of the race day, and perhaps allow the semi-serious racer to be competitive without having to build a bunch of rigs.

Have fun with Footys…Bill H

Dear Bill,

Anything that crosses the finishing line ahead of me is serious! I’ve got a vague appointment with a cat-rigged Razor in Burton-on-Trent when I’ve got this damned think working (too many radical ideas inone small package) so we’ll see.

Best of luck to your man.


…why should Footys be just another version of M or 36/600 only smaller? You said yourself that the 36/600 class only has a small following. Maybe you just wanted a rule where you could build a 36/600 with shorter spacing between stations to use your old designs?

As you are aware this is taking place on another Footy website (Geez - they are popping up all over ) as one person has reduced the lines of a 36/600 PeaPod to Footy size and has just started the stitch-n-glue. With a huge (for it’s size) bow buoyancy, some are waiting to see if this old 1970’s design will compensate and prevent pitchpole at this small size.

The Formula 48 multihull class uses the “box rule” if you want to call it that, with three simple measurements to keep the boats alike (ONLY) in physical size. After that it is OPEN DEVELOPMENT. Length overall, beam overall and maximum sail area are the limits. We did exclude kite sails for technical reasons - but we were determined NOT to interfere with “development”.

It seems to frighten people to no end when the word development comes up - and then follows a mad dash to “limit” ideas - which in turn accounts for hard feelings. “My” views aren’t “your” views - and so forth.

I have been on a crusade to call the darn classes what they are - and stop pretending what they aren’t.

Using the Footy as example here - and it being promoted as developmental … You have a box into which the boat must fit. Is there a reason to go beyond that - it is length, it is beam, it is draft, so why go further. The AA batteries are example - what for - weight control ? Then establish a minimum all-up sailing weight. Sail area - allow two rigs for a regatta, but stop telling folks what sizes they must be - unless you are moving down the path of the IOM Class and wish to identify/specify rig and sail area sizes.

Development ? - not hardly a pure description - more like a class that can evolve inside a number of set parameters. When you talk “development” - have the common sense to limit all the things you are trying to control. The fewer controls, mandates, restrictions, the broaader and more unique the ideas and solutions. If you are really looking for a breakthru idea/design - allow the class to “DEVELOP” (duh) within length, beam and draft parameters.

Just my opinion, of course - I could be wrong. :confused: :cool:

Dick, the idea of a true and complete “Development” class is nice and fine, but it can not really exist, some ort of limitation will have to be always there, you don’t want people to show up with gas powered outriggers at regattas, right?
The Box rule is definitely the rule that allows the most development, within the class specifications…


Gio -

respectfully - before we launch into a deep discussion or debate about development versus limited development rules, please do read the F-48 Rules that I referenced. http://formula48.proboards13.com/index.cgi?board=Frules&action=display&thread=1075599913

As you yourself state… “The Box rule is definitely the rule that allows the most development, within the class specifications…” to which I agree - my point is, and has been, there are too many efforts to regulate the class specifications in a micro-managing manner, … which in turn “strangles” development. If this is what the class wants, far be it for me to stand in the way - I’m just pointing out the fallacy of calling it a development class when it isn’t open for all ideas and designs within a very basic set of specifications - as we did in the F-48 Class, and the class specifications have many limitations for unknown reasons.

I am not saying there shouldn’t be rules/specifications - but I am suggesting that if it is development you want - dispose of any rules which seem to prohibit development, as some of the example I made.

I strongly subscribe to the theory that any proposed rule, needs to have three different points of view or discussion as to why it is needed BEFORE being adopted. The Laser class is one that is a strict one-design, where even paint on the hulls is excluded. Thus - if it isn’t truly an open development class - it has to be a one-design with limitations. If one can stand up and defend the purpose of a rule - and convince a majority of others - then what the heck, I’d have to live with it. But to propose a class as open and developmental, but then add a bunch of caveats seems odd at best.

As to powered boats which you question, the F-48 rules include the words “sailing” - thus - while it may be a “multihull” and an off-shore design gas/electric powered looking catamaran (I guss main hulls with outriggers might be considered a trimaran) they certainly do not meet the basic rules.

My poor little lawyer’s brain is overheating. It seems to me that the difference that between a development rule and a restricted rule is merely one of the rules of interpretation - do we assume by default that somethng is allowed or do we not?

If this is correct, exactly the same set of physical constraints laid down by the rule can be development or restricted - the difference is merely in the preamble defining how they are to be interpreted.

Or have I got totally the wrong idea?


I see there’s some emotion around the rules stuff…mosty from us Yanks, and we sure hijacked this thread, but I guess that’s probably my own fault.

I don’t want to try to defend or to justify all the decisions that went into the rule, or to make judgements about what people think should or should not be in the rule. All are entitled to their personal opinions, and none of those opinions is either right or wrong. What I feel I should do, as Class Secretary, is the best I can to clarify and explain the rule. So I get drawn into these discussions when I feel the rule is being misstated, or misrepresented, or when I think the intent of the rule is being misinterpreted. That has to be somewhat subjective on my part, but I try to be careful in my interpretation of what is said. For the times I get it wrong, I apologize.

In the spirit of clarification, I’d like to point out that the word “development” was never intended by the rules developers to mean completely unrestricted. In fact, the word “development” didn’t enter the picture at all until we had to put Footy Class on the AMYA Class Webpage. The AMYA only recognizes 2 categories. Here are the definitions taken from the AMYA site:

“There are essentially two different kinds of classes. Development classes tend toward encouraging new designs, and One-Design classes tend to focus on restricting development to make all boats as equal as possible. In reality, there is an almost continuous range of types. The dividing line tends to be whether the hull is restricted to a single design, so be aware that some of the classes listed below as “one design” may not be as restrictive as others.”

Since Footys are not restricted to a single hull design, and, we thought, tend toward encouraging new designs, the class fell into the development category.

The way the rule developers were thinking about it was like Angus’s “glass half full or glass half empty” approach, which is consistent with the definition of Open and Closed classes in the ERS. An “Open Class” is defined in the ERS as “where anything not specifically prohibited by the class rules is permitted.” Note that the Footy rules use the term “Open Class” rather than “Development Class” to be consistent with the ERS. At some point, it’s my personal hope that we will reword the AMYA Class Webpage according to the ERS definitions.

Each class in AMYA except the AMYA Open Class, of course, has some number of restrictions. The restrictions of the Footy rule (off the top of my head) were intended to keep the boats in the spirit of one foot long, to provide for simple measurement and certification, to discourage runaway cost escalation, and to allow for a variety of levels of enjoyment of Footys…from the perhaps unfortunate example of the Boy Scout to the most serious designer/builder/racer.

That said, no rule ever makes everyone happy…what one loves another hates. So the AMYA has a process for evolving the rules over time. Each year changes can be submitted for vote. If for example, there are two people unhappy about the battery restriction, one can nominate a change and the other can second that change. It will then go up for a vote of registered owners. Another item might be the shape or depth of the V cut in the box for stern-mounted rudder linkage. Or someone could propose a complete replacement of the box rule. That’s fine…at the end of the day the rules for the class will evolve to be the rules that the majority of Footy owners think is right for what they collectively want the class to be.

Thanks for caring about Footys…Bill H

I am very sorry and I do not want to bring large scale politics into this. However, I am concerned and upset that this class has been hijacked by an AMYA definition. I have read the rules careliessly: it never occurred to me tha anyone in their right mind could use parochial American definitions in a class with any sort of international aspiration. I could not give a fig for the AMYA - my national authority is the MYA/RYA. The sooner this class moves to use proper international standards the better.

Equally, it would appear that I, Brett and anyone else who has the wellbeing of this class at heart must be a member of a foreign national authority in order to influence the development of a class that originated in New Zealand and first expanded (as I understand it) in the United Kingdom. You are in contact with the MYA: I would be obliged if you would copy the last posting and this message to Bill Green, the MYA Footy Registrar.

I am sorry to be negative but I find this type of Americo-centricism offenive.



Angus, I guess my attempt to clarify fell short.

The current Footy rules adopted by the AMYA are indeed the same rules developed by the international group including Brett, myself, Bill Young, and others…word for word. The word “Development” is NOT part of the Footy Class rules. The current Footy Class Rules are completely consistent with the ERS definitions.

I personally believe strongly in the value of an international view of the class. That’s why I agreed to join the rules development team, and that’s the way I’d like to see the class continue to go. I collaborate with Brett on almost a daily basis and we have become good friends through our love of Footys. It would be great if you could encourage Bill Young to get involved here, too. (USA folks, this is NOT the same Bill Young who is our OpenClass Secretary.)

Please don’t take any of this discussion as an attempt on my part to force a new USA version of the rules on the International Class Association. It is my personal fervent hope that the AMYA Footy Class will always be governed by the international rules of the association.

This confusion of “development” vs “open” terminology results from what I interpret as something of an incomplete job of the AMYA’s decision to adopt the ISAF rule and its appendicies. While the ERS clearly defines Open and Closed classes, some of the older AMYA stuff still goes by the less-precisely defined terms Development and OneDesign.

Bill H

So how is the rule changed? Nationalist considerations apart, there appears to be no mechanism for changing it appart from the AMYA one mechanism you suggest.

Please understand that I have no issue with the current administration of the class but I think that whatever international mechanisms there are should be made more transpaent.


Here you go, Angus…this is a copy of the Class Association rules for governance of the class internationally. I’m pretty sure we published this around here some time ago, but before you came on board. Bill Young is your registrar for the UK, Brett for NZ, myself for the USA. Of course, the MYA and AMYA have their own governance rules. I hope that all of the participating countries will continue to support the international association. In the case of the AMYA, that would mean our USA members continuing to vote in favor of adoption of the international rules whenever a change is proposed through the AMYA process I described (as they have for the IOM, 10R and M classes.) For change at the international level, as you can see, every registered Footy owner has a vote on proposals.

"Footy Class Association

Association rules

  1. Objectives of the Class Association
  • To create and maintain uniform worldwide Footy class rules for racing and promotion.
  • To set up and maintain registers of boat numbers, their owners and contact addresses.
  • To develop easy communication between the Association and owners.
  1. Membership
  • Membership is available to an owner of a Footy who applies to the national registrar for a registration number for a new or an unregistered Footy by providing the owner’s name, telephone number and e-mail address (or a contact e-mail address where messages could be forwarded).
  • Membership is available to a new owner of an existing registered Footy who provides the boat registration number, owner’s name, telephone number and e-mail address (or a contact e-mail address) to the national registrar.
  • Membership ceases when a member no longer owns a Footy or fails to inform the national registrar of a change in address.
  1. The Committee

The Committee for the day to day running of the association shall consist of volunteers to act as:

  • the national registrars in each country where these boats are sailed
  • a technical team of at least one member
  1. Terms of reference

Registrars - to issue registration numbers to Footy owners that apply

  • to record registration number, the owner name, telephone number and e-mail address
  • to set up and maintain an e-mail group address or some other method for electronic communication with members
    team - after discussion with the committee to issue class rule interpretations
  • with the committee to draft proposals for class rule changes
  • to issue any updated class rules to members
  1. Rule changes

The committee will ballot members on rule change proposals, with the result based only on a simple majority using a one member one vote basis."

Cheers…Bill H

Thanks very much for that. It should be put in some permanent place.


I agree, Angus. I nominate the Footy Class Webpage http://footy.rcsailing.net/index.php