Unlimited C Class Sailboat Racing Rule (UCCSRR?)

[peterraymond]

The design of the removable tips would be important. I see them as being used to enhance low windspeed takeoff especially on boats like a Peoples Foiler where foiling would be important in winds from 4-5 knots up. There are so many light air venues in the US I think it is critical to design for very early takeoff in this application. Top end speed is not as important....
For racing applications the design would include a low drag tip that is removed and an extension with a low drag tip put in its place. The problem then could be partial span flap drag. Every innovation has its price-the key is designing a system that offers more benefits than it costs in every way.

A reasonable goal for a peoples foiler would be user complexity equal to the original laser. I have to think the launching and assembly would be complicated by the foils, so it seems like you have to be very resistant to anything that complicates the boat. Rather than the lowest takeoff speed, maybe instead you have to go for acceptably low drag in the low rider mode.

If you want it to be all things to all people, it will end up making none of the happy.

 

[Doug Lord]

Yes, that boat would be fast, but maybe not the fastest. Veel heel gives RM to a monhull, but the width of a cat gives more. Although, Veel heel might also help in that the lift from the main foil has a component to windward and that may be a significant benefit.

A monohull is potentially lighter and nominally has less windage. These boats are fast enough that windage is probably significant. The goal is maximum system lift to drag, so I'm not sure how much the power foils help on a very low drag design. On most boats more power is good, even if it raises the sails induced drag, but that was not the case, upwind or down, in the latest AC, and may not be for C-class either.

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Well, be that as it may the 11' Moth has beaten every catamaran under 20' since around 2004 in foiling conditions. If you look at the comparison between an A Class cat and a foiler Moth in SA/ws when the Moth is foiling you can see why.
A trimaran can be designed to not only take advantage of the beam of a multihull but to utilize veal heel as well-for all its benefits.
See: http://www.boatdesign.net/forums/multihulls/veal-heel-multihull-foilers-28372.html

 

[Doug Lord]

A reasonable goal for a peoples foiler would be user complexity equal to the original laser. I have to think the launching and assembly would be complicated by the foils, so it seems like you have to be very resistant to anything that complicates the boat. Rather than the lowest takeoff speed, maybe instead you have to go for acceptably low drag in the low rider mode.

If you want it to be all things to all people, it will end up making none of the happy.

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As I visualize it, the Peoples Foiler would use retractable foils like the RS600FF, Bladerider, Mirabaud and others with the system designed so that it could be trailered with the foils in place. It would have buoyancy pods that would make seahugging a peaceful experience. Light air foil extensions for earliest takeoff might be standard with optional "high speed" tips.
The focus would be an easy to sail boat with very early takeoff. There would be no focus on top end speed. It would not, in any way whatsoever, be "all things to all people".

 

[Gary Baigent]

"It might be that with a tunable t-foil on the rudder you could trim the angle of attack on the foil on the ama and keep it from lifting too much when you are off the wind. Might not make the boat faster, but it might feel better."
Peter, there is an inverted T foil on the rudder but it is immovable and set at zero angle of attack - which works fine. At speed, looking astern, here is hardly any disturbance in the wake. Boat is very light at 650 kgs.

 

[CT 249]

Peter, what you're saying is pretty much what I have on Groucho Marx - but instead of angling the foils to accommodate heel, I've placed inverted V's. These work fine, no ventilation and no crashing whereas my angled surface piercers of before had a tendency to do that occasionally. However the inverted V foils are fixed, at 3 degrees attack, but because the platform has dihedral, the windward foil flies clear of the water. presenting no drag, aside from air that is. But the faster the boat goes on downwind courses, the leeward foil starts providing so much lift that the leeward ama lifts and sets up a rocking motion, then the windward one touches, begins foil lifting and rocks you back again - which is slightly annoying but you can live with it. This is really a case to have water ballast to leeward. On the wind of course, no such rocking occurs, the foil just keeps the float kissing the surface, no matter what the wind strength.

Just been drooling over pics of your foilers again, Gary. They do look absolutely superb; a bit like baby versions of "We"/"Sebago", but more elegant and aesthetic.

Great stuff!

 

[peterraymond]

There are three or four things you can use to have a single limiting factor:
Sailing Weight
Sail Area
Length
Number of Crew

As soon you limit more than one of these, you have a type forming rule.

R

+1 Makes sense to me.

For displacement craft and all boats it seems, the primary determinant of speed seems to be length. I think that is the best single limit for an open class. Still, a length limit might force a type, although the type it forces might depend on the length selected. At Moth length it might be a mono-foiler. At 90' it might be a multi-hull.

Sail area limits are put in place to prevent freaks I think, like the 18 foot skiffs that are so entertaining. Sail area also is old-fashioned, because you can't increase sail area downwind and all of the boats with the same sail area upwind and down look a little out of date, at least to me. This is an out-of-date concept.

Number of crew alone doesn't work, because there are very fast single-handed ocean racers that are huge. A rule that selected for 60' multi-hulls sailed by one crew with self tending sails doesn't seem like a good answer.

There is still sailing weight, which has something going for it, except that to me it seems to reward materials, construction techniques and risk taking, not what we think of as the more normal design attributes.

My choice would be more like the rule for 18's, but with no mono-hull requirement. I'm OK with different sail plans for different wind strengths. The 18 rule has reflected our increase in knowledge over time too as the hull shape and number of crew have both changed since the standard of a few decades ago. This also gives different boat types the flexibility to adjust everything else to fit their strengths and weaknesses.

This general format could be similar to the A, B, C and D classes, except in length, not sail area. I personally think the Moth is too short and if you look at the boats the RS sells, 3/4 seem to be around 14ft or so. In both mono's and multi's a popular length is 18ft and then we have the 25ft cats. Picking similar lengths I would maybe suggest 4 open classes based on length in meters:

5-Open,
6-Open,
8-Open and
12-Open

Maybe I'd tweak the 5-O class to 4.5-O, but the particular lengths are not the point. The point is that people could pick the class based on budget and the structure would support a huge selection of concepts. It would also allow the boat design to be adjusted based on crew weight and wind strength, so it would work well anywhere for anyone. At least anyone who is a great sailor, young and agile.

I don't think this concept will light up the world, but if someone wanted truly open development classes, this is how I'd do it.

 

[Gary Baigent]

Thanks CT. but don't look too close, they, for some reason, keep getting very weather beaten and knocked around. I've always thought that Adrian Thompson's boats were superb, yes, they've had an influence. But Eric Tabarly did this sort of boat first with Paul Ricard - which wasn't the most aesthetic .... but he did it first - and that is still a fascinating boat. The last version, the 75 foot foiler Cote d'Or 11, is being readied for the next Rhum race. She's an old boat now but I'll watch with interest.

 

[CT 249]

+1 Makes sense to me.

For displacement craft and all boats it seems, the primary determinant of speed seems to be length. I think that is the best single limit for an open class. Still, a length limit might force a type, although the type it forces might depend on the length selected. At Moth length it might be a mono-foiler. At 90' it might be a multi-hull.

Sail area limits are put in place to prevent freaks I think, like the 18 foot skiffs that are so entertaining. Sail area also is old-fashioned, because you can't increase sail area downwind and all of the boats with the same sail area upwind and down look a little out of date, at least to me. This is an out-of-date concept.

Among the craft that have the same SA upwind and down are foiler Moths; A Class cats; C Class cats; kites and windsurfers.

So basically their numbers includes the fastest small dinghy; the fastest beach cat; the fastest singlehanded cat; and two of the fastest sailing craft. That's not very 'outdated' in performance terms.

Similarly, the world's top-selling sailing craft, the Laser and Opti, both have the same sail area upwind and down. I think it was just last year that ALL the Laser worlds - from 4.7 to Masters - were restricted for the first time ever, which shows that the class is, if anything, maybe firming its dominance while other craft lost numbers.

So craft with the same SA upwind and downwind don't seem very outdated in terms of grass-roots sailing and popularity.


Number of crew alone doesn't work, because there are very fast single-handed ocean racers that are huge. A rule that selected for 60' multi-hulls sailed by one crew with self tending sails doesn't seem like a good answer.

There is still sailing weight, which has something going for it, except that to me it seems to reward materials, construction techniques and risk taking, not what we think of as the more normal design attributes.

My choice would be more like the rule for 18's, but with no mono-hull requirement. I'm OK with different sail plans for different wind strengths. The 18 rule has reflected our increase in knowledge over time too as the hull shape and number of crew have both changed since the standard of a few decades ago. This also gives different boat types the flexibility to adjust everything else to fit their strengths and weaknesses.

This general format could be similar to the A, B, C and D classes, except in length, not sail area. I personally think the Moth is too short and if you look at the boats the RS sells, 3/4 seem to be around 14ft or so. In both mono's and multi's a popular length is 18ft and then we have the 25ft cats. Picking similar lengths I would maybe suggest 4 open classes based on length in meters:

5-Open,
6-Open,
8-Open and
12-Open

Maybe I'd tweak the 5-O class to 4.5-O, but the particular lengths are not the point. The point is that people could pick the class based on budget and the structure would support a huge selection of concepts. It would also allow the boat design to be adjusted based on crew weight and wind strength, so it would work well anywhere for anyone. At least anyone who is a great sailor, young and agile.

I don't think this concept will light up the world, but if someone wanted truly open development classes, this is how I'd do it.

Pretty much the most open of extant small-craft classes are the 12 Foot Skiff, Moth, A Class, C Class, windsurfers and R Class.

None of them are cheap, so there's no much chance of picking a budget. None of the development class boats are particularly popular.

The open 18 Foot Skiff class has of course died because of spiralling costs, despite the fact that it had professional organisers and TV coverage. The current 18s are a strict one design hull with restrictions on material and rigs.

Interestingly, the runners-up in Moth and A Class worlds have both noted that the designs could not be adjusted enough to compensate for the fact that they had different weights to the winners. Development-class windsurfers, for example, strongly favour very big sailors because the sail area is so large. On the other hand, there's been a huge range of weight at the front of the International Canoe class, because the hulls are so large that the boats can handle a heavy sailor with no problems, while the small rigs and huge leverage mean that a light sailor is not overpowered.

Dunno why any particular class would allow a wide range of concepts. We probably know already that nothing but a foiler or cat would win the smaller classes, and only a multi would win the bigger classes.

I was once one of four guys who created a class with just three rules. It did well, right until the time it got serious and the flaws in the concept came to light. It then shared the fate of just about every very loose class, and died because the costs got out of control and there was so much variation in the designs that you either had to turn up with two hulls and several complete rigs, or you'd have to accept that you had a very slim chance.

 

[Doug Lord]

I like the C Class Cat rule-only with more beam- would be a good measure against existing C Class cats etc.

 

[RHough]

+1 Makes sense to me.
Number of crew alone doesn't work, because there are very fast single-handed ocean racers that are huge. A rule that selected for 60' multi-hulls sailed by one crew with self tending sails doesn't seem like a good answer.

The state of the art in design is driven more by courses than any other single factor.

Make the courses 1-2 mile legs and you get different boats than if you make the course across an ocean.

Rule 52 - 1 crew:

I'll back J Spithill in an A Class Cat to win over F Cammas in an ORMA60 on a short course.

Chris closes one eye to rebut the idea that fixed sail area is an out of date concept. All the examples he gives have something in common other than fixed sail area upwind and down.

"Among the craft that have the same SA upwind and down are foiler Moths; A Class cats; C Class cats; kites and windsurfers."
"That's not very 'outdated' in performance terms."
"So craft with the same SA upwind and downwind don't seem very outdated in terms of grass-roots sailing and popularity."

I would say in terms of grass-roots sailing popularity, it is simple, easy to sail, but challenging to sail well, that is the qualifier.

Moths don't fall into the easy to sail slot IMO, Lasers and Optis do.
Kites and Windsurfers are not exactly easy to sail either when compared to a Laser or Opti either.
A Cats and C Cats are not exactly grass-roots popular IMO.
Hobbie 16's are simple and easy to sail. I'll bet there are more H16's than A & C cats combined.
Lido and Snipes and any number of 2 man boats are easier to sail than 29er's, 49er's, 505's etc. I have no idea about the relative strength of those classes.

For a new development class where crew > 1, I don't think we will see many fixed area boats.

The C Class would not be the C Class without the area limit, but you won't find many people that will try to tell you that downwind VMG on a C Class Cat would be LOWER with the addition of a flying sail.

As fast as the C's are they are dead slow compared to the AC33 multi's in terms of VMG to TWS.

I like the idea of seeing what the limit of VMG to TWS is on water. I don't see any open rule classes that allow that limit to be explored.

R

 

[peterraymond]

Fixed sail area

I didn't mean to get anyone excited when I made that comment about fixed area sailboats. I guess it will sound like I'm denigrating every boat I mention, but I'm not saying a single one is less than a great boat.

Moths are certainly killer performance extreme boats, but how old is original the class rule? Until the wings came along, I personally thought they looked like a boat that had been pushed into a development corner because it was saddled with a waterline that was too short. Now though, other that the rudder, it all looks like it makes sense. Maybe it was just ahead of it's time waiting for hydrofoils to come along.

I would say that it would make sense to me, from a performance perspective, if the C-Class cats only had a sail area limit upwind. Not as pure a concept, but I just read the technical paper in Cogito and they had one crew to leeward down wind. Yes this makes it easier to tune the wing, but downwind they're not at the limit in the same sense that they are upwind.

It might also be that the wing would be less necessary with unlimited downwind sail area. I would expect the wing to still be faster, but one big advantage the wing has is that it can support a higher coefficient of lift. To put a finer point on it, the wing's advantage downwind is that it's less underpowered. If you raise more area you would at least be closer to a lift coefficient that a soft sail could generate.

The C-Class community is small enough though that they can just decide what they want to do with the rules and do it. For the current series I'm sure you don't need to change the sail area rule, but If I were trying to sell a C-Class cat I'd add a flat spinnaker.

Similar arguments apply the A-Class cats I think. They should be faster downwind with more sail.

Still another example is a Contender. I've never even seen one, but from the first picture it's always seemed like a particularly interesting boat to me. Today though, would the Contender have been designed without a spinnaker?

 

[gggGuest]

Today though, would the Contender have been designed without a spinnaker?

I don't see why not. For all that they are currently flavour of the month kites are still not a great solution of singlehanded boats, especially in close quarters situations and confined waters. Hoists and drops are always a pain, visibility is poor and manouvers complicated. And I don't like having more sheets than available limbs. When you sail a high performance two handed boat the mainsheet is more important than the rudder in controlling angle downwind with the kite up. In a singlehander you haven't got that level of control, and sometimes it bites. To my mind the right solution for getting fast singlehanded boats round the track has yet to be found.

By fast I mean a boat that is capable of exceeding gust speed on its optimum downwind angle. A boat that can do this is destined to sail in lulls for much of the time until it can hit the next step in performance, which is to be fast enough in the lulls to catch the gusts.

 

[Doug Lord]

Still another example is a Contender. I've never even seen one, but from the first picture it's always seemed like a particularly interesting boat to me. Today though, would the Contender have been designed without a spinnaker?

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The RS600FF is the only trapeze singlehander on foils-and has no spinnaker....

pix by peter chinook:

 

[peterraymond]

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The RS600FF is the only trapeze singlehander on foils-and has no spinnaker....

pix by peter chinook:

See, the boat was so boring they had to add foils to make it challenging. Or, sailing without a spinnaker left them so off the pace they needed the crutch of foils to keep up.

Actually, don't take me seriously on either of those statements. Like gggGuest, I'm not sure I'd want a spinnaker on my personal single hander. I think I'd rather sail in more wind. But, on light air days when not much is happening down wind and I'm going to be sailing in the same direction for over a mile, then maybe they'd be fun to play with.

 

[CT 249]

Peterm, most Mothies would (or would have) agreed that the boats were "too short" in some ways (although that may have changed with foils). But to many people (Mothies, 12 Foot Skiffies, some 14ers, some Nat 12ers) the fact that their boats are (from some eyes) "too short" has always been a lot of the thrill. It makes them more responsive and (in many ways) more challenging to sail. Plus it keeps costs down.

It seems very significant that most of the remaining dinghy development classes (Moths, Rs, 12s, 14s, NS14s, Nat 12s) are short. There's less development in the bigger classes, perhaps because of the sheer expense.

The 18s, for example, aren't a great model for free development rules because they now have one design hulls and restricted rigs. The open design rules became uneconomic, because there was so much room to throw money at the issue. The tank testing for the stern sections of Bradmill (one of the great unrestricted 18s of the mid '80s) cost about the same (IIRC) as a complete new Etchells. Even with TV coverage, sponsors baulked and then walked away. The model was not practical.

The popular development classes also have restricted rig sizes, because a simple length limit with no SA restriction almost invariably ends up with a boat with a massive rig crammed onto a small hull, as in the 12 Foot Skiff and the ORMA 60 tris. That leads to something that is costly and hard to control for the speed. That can be huge fun for 12 Foot Skiff sailors, but can lead to problems, which is why ORMA 60s had rig restrictions put on and experts like Nigel Irens said that the limits allowed rigs that were too big.

Interestingly, the 12 Foot Skiff hull has not had a huge amount of influence on other boats, because in an unrestricted-rig boat the hull design ends up being dominated by the need to control that huge rig.

Adding SA downwind is logical in many ways, but it's also bleeding expensive. The classic case would be the International Canoe, where adding a spinnaker increased the sail area by 300% (and a lot of dollars) but only increased speed by 3.5%. Or look at the F16 cats, where adding a spinnaker increased sail area by about 100% but again added only 3.5% to the speed. The MG14, which is basically an NS14 with trap and kite, is only marginally quicker than the NS14 for (all else being equal) probably 15% extra cost.

Such figures do seem to indicate that it is quite likely that future classes will come out without spinnakers. Personally, I love kites and it does seem illogical in some ways to go downwind with the same SA you carried upwind, but whether the fun and speed of a kite balance the costs, rigging hassle and sailing hassle for the average sailor is another issue.

Conversely, classes where only SA are controlled tend to become very long for the SA until they can become quite slow and expensive for the performance. The Square Metre boats are a classic example - stunning craft, but not quick for the buck or length AND they quickly had to be subject to sub-classes and restrictions because of the excessive development that lead to overly expensive boats.

It all leads me to think that, for all the hate directed at rules, they are actually incredibly good for development, because going to the extremes in length, sail area whatever is very rarely cheap (in terms of bucks for the speed) and very rarely creates a boat with widespread popular attraction.

A classic case in favour of dimensional limits would be the R Class, which has extreme restrictions on SA and length considering its crew (110ft SA originally and 12'9" LOA are tiny for a boat for two men) and has sometimes arguably been THE most advanced dinghy class in the world, despite coming from an isolated area in an isolated country.

The open class I helped draft the rules for died because it allowed in craft that were too tippy for the average skilled sailor, too expensive, and too fast for everything else. Pretty quickly, the fleet walked away from the few Olympians sailing the class, and then the class died. So there is now NO development in that class. Instead, a sub-class (with those restrictions that are so often criticised) is still developing, because the restrictions created something that people could actually buy and sail.

Another example of the good that restrictions can do is the foiler Moth. Cats and windsurfers were banned from the class years before. Imagine if windsurfer rigs or cats had been allowed in the Moth - the class may have become just another windsurfer class (and the open development classes in boards have also died due to excessive costs and development) or another cat class (like a baby A Class, which would have been fun). But neither cats or boards developed foilers that worked around a course. If cats or boards had taken over the Moths, we may never have had the foiler. Would that have been a good thing?

And on the other hand, the signs of the huge growth in the class that some spoke of still seem elusive, while more restricted versions of the Moth (Europe, NZ Moth, US and European Classic Moth) still seem fairly healthy. The less-restricted International Rules have not lead the class towards a promised land of huge fleets. One wonders whether a more restricted version of the Moth, which forced it to remain closer to the Aussie scow or Europe style, could not have been much more popular than the current class (which is not to say that such restrictions would be a good thing in other ways).

In all, it's just too easy to see restrictions and rules as evil things. There are always restrictions, whether of LOA or SA or $ or handling. Choosing other restrictions (such as length AND sail area, plus perhaps rise-of-floor rules) can create a more balanced and economical class that can flourish and therefore lead to many more developments than a class that is so loose that it dies.