Possible Class of Small Ocean Racing Sail boat

[sharpii2]

Dear Thor:

Thank you for the links. I checked them myself and found the rule imfo volumous. It seems the sm rule ended up restricting a lot more than sail area.
(which, in my opinion, they didn't restrict fairly at all.

to summerise: The jib was measured as 85% of the fore triangle (no matter what its actual size) and the main was measured for its actual area. This way large headsails could be used which would favor ever taller masts.

At least tall for the technology of their time.

It seems later, in order to keep the already built boats competitive, they started creating a whole lot of hull restrictions, then rig restrictions on top of that.

It seems like they settled on a basic hull concept and restricted new boats to following it.

This is the absolute opposite of what I have in mind.

I do see, however, a need to have a minimum freeboard restriction added to my rule.

Perhaps a 0.5m midship or 1/3rd the Beam midship, whichever is greater, with the added stipulation that no part of the topsides can be lower than that.

Without this, the 1x19 class boats could end up looking like ballasted or rafted sailboards.

Without a doubt, boats of this class will be wet and cramped (to limit surface area) and have very short ends, but I do believe they will make handy single handers.

And since there is no loophole regarding headsails, I think this proposed class could do a much better job at discovering the best all around sail rig with a presumed prejudice (but not neccessarily) toward more downwind oriented sails. This is because most, but not all, long ocean races (as well as voyages under sail) tend to be downwind.

Bob

[Raggi_Thor]

I think it would be great with rules that inspire to build low cost boats. Small sail area should work in that direction, limited draft also. So this could be something new :-)
A radical rule in this regard would be a maximum price, like we have in car racing, if someone offer you 5000NOK (700USD) you have to sell!

[CT 249]

I think you'll find the square metre restrictions were NOT intended to preserve the older boats, so much as to stop excessive development of every lighter, ever more fragile hulls. This is a very common theme on all (or almost all) such classes, from the Half and One Raters, to the German "Free Renjollen" dinghy classes, to the 100 (or 75) square metres. Designers simply created longer, lighter boats which went faster but fell apart in a year or two. So just about all such classes died or they introduced either minimum weights (10 square metre Canoes), scantling requirements (Renjollen), or girth measurements that meant the boats had to be heavier and were stronger (square metre classes).

One problem with unrestricted length is that the boats end up being expensive for their speed - some 22 square metres were (IIRC) 39' long - longer than the earlier 30 squares. So a winning 22 was still slower than an older 30, but it cost much more than an earlier 22 OR an earlier 30. The extreme boats had less speed per dollar.

Length is a key to all-round speed, so while square metre classes produce great boats they will basically always develop into long boats. The classes that restrict length but don't restrict sail area (or allow very big rigs) also end up being expensive for their speed (all else being equal).

So while the "no restrictions" route seems great, it has a lot of problems in reality.

In dinghies, the classes that created many of the innovations were Int. Canoes, International 14s (pre 1953 and modern), Merlin Rockets, Renjollen, Cherubs, National 12s, NS14s, R Class, Moths, and maybe 18' skiffs. Almost all of them were restricted in both rig AND hull dimensions, and they normally had fairly small rigs so the emphasis was on efficiency rather than brute force.

I like many of your ideas, but even in monohulls the fastest boat to your rule will not look anything like the "standard" sort of boat as it seemed you wanted it to.

[sharpii2]

Originally Posted by CT 249

One problem with unrestricted length is that the boats end up being expensive for their speed - some 22 square metres were (IIRC) 39' long - longer than the earlier 30 squares. So a winning 22 was still slower than an older 30, but it cost much more than an earlier 22 OR an earlier 30. The extreme boats had less speed per dollar.

Length is a key to all-round speed, so while square metre classes produce great boats they will basically always develop into long boats. The classes that restrict length but don't restrict sail area (or allow very big rigs) also end up being expensive for their speed (all else being equal).

So while the "no restrictions" route seems great, it has a lot of problems in reality.

I like many of your ideas, but even in monohulls the fastest boat to your rule will not look anything like the "standard" sort of boat as it seemed you wanted it to.

Thank you CT.

You are right, of course, That without Scantling or length limits, the boats will become very long and fragile.

To combat this, I decided to go with the minimum surface weight approach.
Every sm of the 1x19's hull and deck area must weigh at least 7.8kg.
This way, the only way you can make the boat longer is by either making it narrower or heavier.

Added to this, are the requirements that the boats should be able to cross an ocean and carry a 452kg payload.

I will consider adding a length limit only in desperation and only after I become convinced that mere minimum surface area wieghts won't do the job.
I know it could come to this. 9m is the number that comes to my mind incase it does. It must be rememberd that the sm classes were invented before surfing and even (under ideal conditions) planing keel boats came on the scene (mostly after WW2, by my understanding), so length is not neccessarily the best way to go for speed today as it was back then.

I have already decided to revise the rule some. Min cabin ht., min freeboard, and min cabin dimensions (and I mean very minimum) will be added as well as some cockpit dimension and placement rules. the old stuff will stay the same, but new stuff will be added.

I had hoped that I could come up with a viable class that could fit on one page. Now it looks like around three. Two to define the class and one to suggest what to do if the newer boats out perform the older ones by too much.

When I get this done, I will post it as an attatchment in an old Word format (I can't afford adobe).

Thanks everbody for your comments and suggestions.

Bob

[CT 249]

Interesting idea about skin/weight rule.

Even in planing boats like skiffs, for all-round performance longer is faster. The 18s are not troubled by the 16s, the 12s have much more rig and about a third of the weight of the 14s but are probably slower apart from in light winds (it's hard to say since modern 14s rarely race modern 12s). I've asked some of the top 18' skiff designers and they reckon a 20' skiff would be faster than an 18.

Same in small cats - the Formula 16HP weighs 104kg compared to the F18s's 180kg, yet the F16HP is only about the same speed because it's shorter (and has a smaller rig).

These are not meant to be destructive criticisms, I think the idea of a sail-area restricted class is much better than the LOA restricted classes which tend to be expensive and fat for their LOA and speed.

[sharpii2]

Originally Posted by CT 249

Interesting idea about skin/weight rule.

Even in planing boats like skiffs, for all-round performance longer is faster. The 18s are not troubled by the 16s, the 12s have much more rig and about a third of the weight of the 14s but are probably slower apart from in light winds (it's hard to say since modern 14s rarely race modern 12s). I've asked some of the top 18' skiff designers and they reckon a 20' skiff would be faster than an 18.

Same in small cats - the Formula 16HP weighs 104kg compared to the F18s's 180kg, yet the F16HP is only about the same speed because it's shorter (and has a smaller rig).

These are not meant to be destructive criticisms, I think the idea of a sail-area restricted class is much better than the LOA restricted classes which tend to be expensive and fat for their LOA and speed.

Thank you again CT.

What you just said brings up an interesting question: would the f18 be faster than the F16HP if it had to wear the F16HP's smaller rig.

That is in effect what it would have to do under the proposed 1x19 class.

It is very possible that it could, at least in high winds where righting moment is more important than sail area. I suspect, however, that under average conditons, the smaller, lighter cat would have a slight abvantage.

The question becomes whether the high wind avantage of the larger, heavier cat would be so much greater than the light wind advantage of the smaller, lighter cat that the larger cat would almost always win.

One of the big payoffs I imagine from this proposed class (if it ever did get off and running), would be the enormous data it could avail. It could cetainly answer the above question amongst many others about optimum average boat speed under very limited power.

Even in keel monohulls, boats that can plane and /or surf regularily can have bursts of speed that are much higher than their non planing sisters. even if the non planing boat is much longer. I would not be surprised to see a contestant go to that strategy.

That being said, I would not be surprised to see it fail more than it succeeded either. But it would succeed at least sometimes. And maybe that's the point. This could be a low power boat speed laboratory where risks are (relatively) low cost and knowledge gained could be applied to much larger craft.

In veiw of what you have said, I realize, that it would be prudent to put my thumb on the scale a bit to prevent real monsters from being born.

I have decided to limit the length to 9m.

A 9m long boat (whose draft is also restricted) with a 19sm rig would look in profile very undercanvased. Kind of like scaled up sailing kayak or canoe .

I think it would look cool. How about you?

Bob

[sharpii2]

Hi everybody.

I have just revised my proposed class rule that is known as the 1x19 or 19x1.

Due to warnings and suggestions by Ct and others, I have decided to limit the length to 9m.

Other changes include:

minimum freeboard, some minimum cabin dimensions, maximum cockpit dimensions as well as some (I hope) sensible cockpit placement rules, minimum keel strength requirements, and a breif suggestion of what to do if older boats get out classed by newer ones or if newer boats are introduced that are slower but have 'compelling virtues' that make them otherwise desireable for some members of the fleet who may not join otherwise.

I hope that all of you who have accessed this thread will be able to open this attatchment. If, for some reason, you can't, please let me know by email or by posted message.

Hope you all enjoy.

Bob

P.S Oops. It looks like I need to reformat my attatchment.