>>..., the ARC17 is a beach boat, ... It is a one person boat or a two person boat. It comes unirig or with a self tacking jib. You can even add a spinnaker with launcher to it. It is a totally flexible boat for the beginning beach cat sailor.
>>This is a different approach from anything anyone else builds and hopefully some newcomers to our sport will find this boat attractive and purchase it
A different approach from anything anyone else builds ?
Cognitive dissonance is running rampant.
Wouter
Hello Sail7seas,
Here's what John Pierce, builder of the Stealth, had to say about "shared lift and CE migration and how to live with it".
Bill
Yes I agree, I have always used the shared lift idea in my boats, both those I build and when I sailed T's and others, Whether the boards are forward or not, the same effect can be got with what ever size boards/rudders are chosen, its just about the position of CLR against CE of the rig, however with existing classes obviously board position is fixed.
With the boats we build, we go down the raking the mast back route to load up the rudders, and rake back the spinnaker luff, however we do have large rudders, one thing that compromises most boats that now carry spinnakers is that most class rules limit pole length to 80cm beyond the bow.
John Pierce and I agree, Sail7seas. We are on the same page.
I don't know why one poster wants to say that when you put an additional sail up in front of the mast on a pole that sticks out well beyond the bows and has an area equal to or greater than the base sail area of the boat, it does not move the center of effort forward significantly when in use. This is putting your head in the sand. It is not a farytale. It really happens.
>Loading up the rudders by mast rake or loading up the rudders by placing the daggerboards forward both lead to the same end result.<
This is a true statement but incomplete. Raking the mast back or moving the CBs forward will trim the boat out properly with spinnaker up. This is fine, AOK.
The problem is "what are you left with when the spinnaker is down and now you are sailing to windward sloop rigged"?
If you have chosen the "rake the mast back route" you are left with an overloaded rudder and underloaded centerboard and this is draggy underwater. If you go with "move the centerboard forward and downsize it and upsize the rudder", you eliminate leehelm with spinnaker up and the centerboard and rudder are in balance, less drag, sailing to windward with spinnaker down. I'm getting out of breath saying this, Sail7seas. I hope we are communicating.
I have no experience with model boats and model boat testing. On any sailboat there are many interactions with changing mast rake. It is a complex subject.
Good luck with your model boat racing,
Bill
Hi Wouter,
We live in two different worlds/populations when it comes to catamaran sailing. I saw two T4.9s for the first time in my life two weeks ago. This F16 class stuff must be big in Europe but where I sail, it is so small I can't see it. I understand the T4.9 is a one or two person boat. That's fine, but again where I sail, I don't see them. No US builder builds a one or two person boat, boardless beach cat, that I know of. Hopefully both classes will prosper.
Good Sailing,
Bill
C'mon Bill,
While wouter does act like he is from a different planet, cat sailing is not that different in europe.
There are more f16s in the U.S than europe. The European Class president doesn't even own one(wouter).
Your claiming all of these unique options for the ARC 17 or any other SC/ARC is typical of your bull.
The ARC 17 is sold like a Chevy pick-up, any combination of parts and accessories.
>>..., the ARC17 is a beach boat, ... It is a one person boat or a two person boat. It comes unirig or with a self tacking jib. You can even add a spinnaker with launcher to it. It is a totally flexible boat for the beginning beach cat sailor.
>>This is a different approach from anything anyone else builds and hopefully some newcomers to our sport will find this boat attractive and purchase
it
How it that different from me buying a Tiger and sailing it double-handed without spinnaker,
Or D-H without jib,
Or single-handed, w/self-tacking jib and spinnaker ?
Or S-H, w/spinnaker, no jib
Or S-H w/self-tacking jib
Or S-H, Uni-rig?
Or, gosh, I could sail it D-H, w/self-tacking jib and spin and race in the Tiger Class and the NAF18 Class and take honor in any victories.
No Bill, the difference is not how the ARC 17 is built, it is how it is sold.
The SC/ARC 17 has no Class rules, no Class association, no Class events, no Class competition.
Are there ANY Class rules for ANY Supercat/SC/ARC boats?
Where is the Class Association and who are the Class officers?
>Are we communicating?< 'give me break, I'm on your side'
I got it two days ago, I was wondering what instigated Wouter to use comments
like "farytale" and "smoke and mirror" and "cognitive disonance".
If I were to choose between John P's design or your design.
With ALL else being EQUAL for a balanced design.
(solving the problem two different ways)
It would be yours, Bill. sorry John.
For two reasons, first, larger sweet spot for CE migration.
Secondly, Luff perpendicular for more acceleration
based on my model testing of mast rake (see previous post)
More cognotive disonance, please (opps, can't use that, it's Wouter's phrase)
Hello Bill,
Of course the F16 and Taipan classes can only hope to sell as many boats as the ARC-17 and SC-17 class have sold so far.
Without this great 17 foot product line many of us would never have seen the light of starting up a class for the sailor looking to singlehand and doublehand a high performance spinnaker boat.
It seems thought we have made a mistake by opting to allow boards. A boardless design like the 17's is indeed superiour. Our mistake but we can't have everything, can we.
And of course we in Europe have the nacra 5.5 sloop and uni which the US hasn't so indeed you must be the first US builder to offer such a flexible boat.
It is also our wish that both classes will prosper. Although it is already a given that the ARC-17 will be extremely succesful. The F16 class will have a lot of catching up to do with respect the 17's. This omni present class has indeed set the benchmark to which we may only strive to achieve as well.
It is also great to see that Yves Parlier ( http:/
Lets hope he does not forget to bring a compass along to take the necessary measurements.
I'm sure that in a 100 years the SC-17 and ARC-17 product line will be viewed as the mother of all modern high performance catamarans. They will be present in all nautical musea as the prototype beach catamaran and sure enough it will be THE catamaran in the olympics.
Good Sailing,
Wouter
Maybe all has been said about it and the only thing left to do is for somebody to build such a superiour design under the A-cat, F18, F16 or F20 rules and proof the theory.
I for one, am very interested to find out how efficient a lift providing rudderboard is while travelling in the wake of the hull and daggerboard. But that is just my university hydrodynamics course speaking.
Wouter
Sam Evans wrote this bit : "The ARC 17 weighs 11.8% less and has a 12.6% larger main, a 14.1% larger jib, a 28.3% larger spin, (20.6% larger sail area overall) than an F18."
Wow. Sounds like a really powerful boat.
But then Bill says it`s a beginner`s boat, NOT built for performance ? Take a Hobie Tiger, reduce the weight by 11.8%, and increase the sail area by 20.6%, and you have a really tame beginner`s boat.
Ok, I get it, aimed at the American market, where either they have no wind, or the sailors are REAL heavy.
My guess is it gets really interesting with the kite up in around 15 knots, looking at the sail area comparison made by Sam. I`d love to see one, but in a nice 25 knot Cape South Easter. I hope the underside of the trampoline is made from UV-protected material, `cos it`s gonna see a lot of sunshine !
Please Bill, be honest about the intended design - It`s meant to be fast & hairy, don`t try flog it off to beginners. Some of them might be fooled by your marketing campaign, buy one & be scared off of cat-sailing for life.
Tell us it`s faster than a Tornado, a F18 or whatever you like, just don`t tell us it`s for two teenage girls who are just getting out of Optimists.
I`m sure it`s a great boat, just seems a pity that it was designed to purposefully fit nicely between both Formula classes, that way it doesn`t have to compete with either. It`s interesting that some folks will buy into the "in-betweener" rather than something that can be raced against boats of very similar designs.
I`m also confused by the fact that it was designed for use as unirig, double-handed, spinnaker or non-spinnaker use, yet this discussion thread is highlighting how critical the CLR position is for each use. Does this mean that the CLR is along the entire length of the hull, as the Dart 18 was meant to be ? If so, my comment on the Dart 18 is that it`s really crew-position sensitive, as well as mast-rake sensitive, and is sailed with a lot of aft rake by the faster guys. It has a deep-v shaped hull along the full length to provide lateral resistance, yet still goes sideways almost as fast as it goes forward, and can`t handle a spinnaker, and also steers like a pig (my nickname for my Dart was in fact "pig". I did love her though.)
I hope you`ve managed to overcome all these obstacles in designing symmetric hulled boardless hulls - in my experience these boats aways have very heavy steering tendencies. Like I said, I`d really love to see one, sounds like a good fast boat suitable for scaring the living daylights out of beginners with.
Cheers
Steve
From my limited experience sailing on an original SC-17 it was about the easiest cat to sail I can imagine.
You really could submerge the bows without worrying about pitchpoling. The boat hardly slowed down. It was smooth, quiet dry and the steering was as light as on a laser. The hull shape was comfortable for trapezing and hiking. There were no sharp edges anywhere as I recall. The boat tacked easily. It seemed to sail best upwind trimmed down by the bow somewhat. It was fast, but deceptively so. That sounds like a good beginners boat to me.
It makes perfect sense that the boat should balance well with many different sailplans. The center of pressure on those hulls should be located very far forward due to their shape. If the rudder angle is close to zero the center of lift is far forward. As rudder angle increases the center of lift will move aft.
I have not sailed a new one yet. It looks like an ideal cruising boat for the Chesapeake Bay.
Talk to you later
colin pitts
All boats are a compromise…The SC/ARC 17 is just one of those rare breads that walk the razors edge with uncanny finesse…Yes there are faster boats, yes there are other well built boats, Yes there are many other board less boats around, yes there are other easy to sail boats out there…but no one to my knowledge has combined this level of performance, very forgiving sailing characteristics, complete flexibility of solo/double/W/WO spinnaker with a board less design.
I have never sailed the ARC 17 but I did own a SC 17 for a number of years (and I just bought another one). Unless you have sailed this boat you don’t have a clue…It makes sailing…and sailing fast….soooo easy.
The vast majority of cat sailors are not racers. For the people who just want to go out for an afternoon and enjoy the water….going fast with their spouse/girlfriend/boyfriend/son/daughter….this is “The Boat”…near bomb proof construction…no dagger boards to spit open your hull if you run up on a sandbar…easy to launch through the surf…eats up rough water like candy…easy to right…holds a lot more crew weight than most it’s size…no pitch polls! If you find over complicating things enjoyable, then this is not your boat…if tweaking an endless number variables is what you are all about, then look else where.
As far as SC/ARC avoiding competition…you must be joking right?…the SC 17 has been out since at least 1981 that I know of…maybe even longer…how long has the formula boat classes been out? F-16?…F18?….F18HT?…F20?…(I think the Formula idea is great, just don’t accuse an established boat of being elusive of competition)
Why did everyone hop over the 17’ boats (SC 17, Hobie 17, Inter 17) and start new classes? Instead of making a F-17 class?…With all due respect, the SC 17 was in production when some of its current critics were in grade school or maybe even in diapers…
It was a great boat when it was conceived, and 23-24 years latter it is still the benchmark for board less beach cats. If it’s not… then why is everyone (except it’s owners) complaining that the boat is so much faster than it’s assigned PN…
In fact that seems to be the same complaint about the SC 20 Bill raced a few weeks ago…Make up your mind…either the SC/ARC designs are unfairly fast, or Mr. Roberts design concepts are “smoke and mirrors”…you can’t have it both ways!
Bob
I found the SC17 to be a lousy beginners boat. Nothing for the crew to hold on to on deck. sharply rounded decks very uncomfortable to sit on. The only time i had a crew get hurt badly was on one in a lake. the boat dived the bows under sharply and quickly and came to a sudden halt when the massively draggy main beam hit the water. With nothing to hold on to the crew injured her knee after being flung forward.
My friends wife also hurt her back when they tipped over. nothing for her to hold on to.
I theorize that the forward canting rudders have something to do with the bows of the supercats wanting to dive all the time.
Also the 17 was meant to be a 2 up boat when first sold. that's why they made a 15 for 1 person. There are boardless boats from many builders that can be sailed by 1 that were originally designed for 2.
My memory of the symetrical boardless cat evolution of the 70s-80s is as follows.(not including the kind with fins-dart type)
Sizzler-aluminum hulls
G-cats
Supercats
Trac 16
The Trac 16 was an improvement over the Supercat IMHO.
There was nothing faster than a G5.7 off the wind in the days before the assy. We worked our way up to top 3 once at Texel on the downwind after a mediocre start.
The whole point comes down to the fact wether the ARC products are fast because of efficiency or because of the huge rigs they feature. The problem here is that without having a really comparable design using the "normal setup", it's hard (if not impossible?) to tell wether any speed increase is the result of superior efficiency or just the result of having a bigger engine.
Last year the Dynacat F18 (with planing underside, hard chines, and step) was launched; it didn't make an impression in the F18 class and wasn't seen to beat the "normal" F18 designs. Therefor the conclusion is simple. Now assume that the builder Mattia had put 20 % more sailarea on it, reduced the weight and made it wider as well all resulting in a boat that was a somewhat faster than a standard F18. But how much of the increase in speed was the result of the sailarea, etc and how much of the planing hull ? It is very possible that the planing surface made the hull less efficient and therefor slower while the increase in sailarea, etc was still enough enough to still make the overal design faster. We would never know without a proper reference boat. And the ARC product line is so off in specifications that there is simply no reference boat for any of them.
It appears that all ARC's are underrated in PN despite any outcome of the question above. Bill claims the designs are surprisingly fast in various posts as others, like you, do as well. The SC's are so much more efficient and fast ? Than why is Prindle 18 = 74.5 ; when SC-17 with 13 % more sailarea on taller rig = 73 = 2 % faster. Note also how the SC-17 = 73 = only 4 % faster than a H16 = 76.1 while the SC has no less than 15 % more sailarea than the H16. If anything; the ratings of the SC-17 are remarkably unimpressive considering the rig that sits on it.
Note that the sailarea's of the H16 and P18 are as good as identical. The weigths of both boats are relatively close as well. Increases in waterline therefor can only account for some 2 % speed increase. Please also note that the OLD SC-17 has more sailarea than the F18 = 63.5 as well. So somewhere a significant portion of all that power is lost in order to arrive to ratings that are 11% (spi) to 15 % (no spi) apart. This actually signals inefficiency !
So what is it ? You can't be more efficient and alot slower at the same time. Are the ratings correct and is the setup less efficient because the SC setup only achieves respectively 2 % and 4 % increases in speed for 13 % and 15 %increases in power ? Or is the setup more efficient in addition to having more sailarea and are the PN's are way off ?
The contradiction is not in the complaints but in the claims !
Therefor we can definately "have it both ways".
The refusal to adres this glaring contradiction and camouflage it with lenghty explanations using unprovable claims is the part I named :"smoke and mirrors"
The diaper comments fall fully under the smoke and mirrors description. Or else we must claim that Ellen McArthur can never win a race because she was still in diapers when all other Vendee Globe and mini sat sailors were already winning their first opti races.
Wouter
Your comments lead me to question if you ever stepped foot on a SC. I use to take my eight-year-old daughter, and 5-year-old son with me all the time on my SC 17. Never once did I lose either of them overboard, and they never lacked for something to hold on to. I never experienced “the boat dived the bows under sharply and quickly and came to a sudden halt when the massively draggy main beam hit the water.” My sailing was predominantly in the Atlantic Ocean out the Ft. Pierce, Inlet and along the beach. We are talking waves here… with heavy chop on top of the swells…the boat absolutely loved rough water.
The actions you described were quite common occurances for me when I sailed a Hobie 14…but I never experienced them on the SC17.
Bob
Wouter…my friend…I did not mean to be offensive in my diaper comment…only use it for dramatic effect in stating that it is ludicrous to say that a 23-24 year old boat is avoiding competition when it was designed, and in production just short of two decades before these new classes with their self determined rules even existed. It would be easier to argue that the new classes should have been built within the 17’ format ( SC 17/Hobie 17/Inter 17/Nacra 5.2).
Surly, you must know that a boat is designed around a whole group of variables…and only becomes a superior design when all are working in harmony for the intended purpose along the chosen design path…why then does every one keep insisting Bill Roberts take his well balance designs and bastardize them to fit into the latest manifestation of catamaran rules? If one of the designs were changed to fit the current trend and it suffered a performance loss, what would that prove? Nothing!…The boat was designed to work a certain way, in certain conditions, within certain physical perimeters.
If you reduced the sail area or beam to match that of another hull design that cannot carry as much sail because of pitch poll problems, have you proved anything? All you have done is limit a design, which has superior pitch poll resistance. And in effect excused the poor design on the new boat. Is this progress?
I would say the SC series has been kind of a reality check for those who have fooled themselves into thinking that catamaran design has made progress in "leaps and bounds" within the last 20 year time frame. It really takes the pizzazz out of marketing High Tech and/or High Performance classes when those pesky 20+ year old SC’s keep coming back from the grave with a few sail tweaks to beat the latest and greatest high tech wonders….
Why can't we have room for both...designs which are free from artifical restraints on length, beam, weight, sail area, and the "effeciency" design aproach within constrictive perimiters you are so fond of? Because when you look at the big picture, and the time line of catamaran design, it looks as if the F16, F18, F18HT, F20 classes are the new guys on the block crashing the party...not the other way around.
Bob
I think Wouter's comments were more along the lines of; if you really want to prove superior design elements, then design it within the arena of other existing designs. For example, if I build a go-kart that's twice as wide and has three times the engine against a standard, more conventional, go-kart and win - what have I proven? If I want to prove that my go-karts designs are faster, then I should build my go-kart within the current popular parameters. By all means, we should build the wide one if it will sell, but we can't really get excited about having superior design elements based on the fact that we're beating more conventional ones. To say that these boats should be a "reality check" to boats that are designed within different constraints is a bit of a stretch. If you took the SC20TR, lopped 4 feet off it's beam and 6' from it's mast such that it falls in the same category as the boats we seem to be claiming superiority over, things could look a bit differently. Where do you think an SC20TR would place racing boat for boat with a carbon Marstrom 20 (even though the Marstrom is still not as wide and doesn't carry as much sail area)?
Bill himself has indicated that the rating on the ARC17 is a bit soft and it's public knowledge that the rating on the SC20 is not very accurate (A Nacra 6.0NA owes a SC20TR, who's mast is nearly 6' taller and beam is 4' wider, time). The SC / ARC boats are more powerfull and faster than their ratings. So we can't really point to race results to say that one is better than the other. The standard for comparison is known to be faulty.
Don't get me wrong; I like the SC20 and the ARC series, I like the idea of a 12' wide boat, or experimenting with the boundaries of the shared lift concept, or adding more sail area to make it faster - but if these concepts are so revolutionary and successful, why don't we see a boat in the highly competative classes and formulas with these features? If it's really because all the other manufacturers are dumb, why don't we see an ARC conform to one of said classes to prove it? I guarantee that if a 'shared lift' ARC F18 was capable of outruning most other F18s it would sell like there is no tomorrow - ARC wouldn't be able to build them fast enough.
Why not constrain what really matters rather than putting artificial constraints on sail area or length? If you ask the wrong question you are unlikely to get the right answer.
1) Cost. The average annual cost over the lifetime of the boat is really important to many of us. Do I need to buy new sails every 2 years? What else do I have to replace on an annual basis? Will the hulls go soft after 10 years of hard sailing? Do I really need to pay an extra $2000 for carbon pre-preg hulls or can I spend $200 on a larger sail plan and go just as fast?
2) Real Performance. Is the boat still fun to sail through powerboat slop when the wind is gusting to 11 knots true? Can I make it home in one piece when the wind cranks up to 30? How wide is the range of conditions that the boat is fun to sail? Some of us have to plan our sailing days long before the weather forecast is reliable.
3) Setup. Can the boat be set up (from the trailer or cartop) by the number of people who will sail it - assuming one of them knows how to assemble it? Can this be done quickly enough to sail after work? If it is a singlehander - can you put it away alone in the dark?
4) Reliability and reparability. What is the mean time between failures that waste a good sailing day? If the boat gets holed by a floating log can I repair it myself?
5) Safety. Could the intended sailor be injured seriously as a result of the boat's design? Sure - some degree of risk may be accepted by the sailor. I would not want anyone to alter something that cripples to the performance of the boat just to make it safer, but don't build in booby traps.
6)Maintenance time to sailing time ratio. How many quality hours do I spend working on the boat versus sailing it?
7)Versatility. If the boat is designed for 2 can I still cruise with 3? Can I still sail it alone? Can the boat go racing one weekend and cruising with the kids and dog the next?
I want the fastest boat that is designed around these constraints, not some arbitrary number intended to limit performance but not cost.
colin pitts
I guarantee that if a 'shared lift' ARC F18 was capable of outruning most other F18s it would sell like there is no tomorrow - ARC wouldn't be able to build them fast enough.
Jake, you bring up great points...
Bill, it sounds to me like the gauntlet is out, fear not the challenge! Respect the outcome....
Hi Sam,
We are communicating better but still not totally.
It is no bull that the ARC17 has options of unirig or unirig plus jib or uni rig plus jib plus spinnaker. When you get to the order boat form, the orderer checks off the options they want even down to the color of the spinnaker.
Here is an example of our communications problem. When I talk about beach cats, I am talking about a small catamaran WITHOUT dagger boards; a boat you sail on and off the beach. To the beginning sailor dagger boards can be a real problem. Try coming in through even small surf with boards down. New sailors sometimes forget about the boards. I've seen it happen and sometimes it is not pretty. The ARC17 is a "keep it simple" boat. If you could see how it is rigged, I'm sure you would agree. Comparing it to a board boat is a non contest. The 17 is a boardless boat a with low aspect ratio sail plan. It is not intended/designed to be fast to windward. The 17 always has always been fast on a reach and downwind. This is the way beginning sailors like to sail. If they want to race at all, they want to drag race on a reach. The ARC 17 is not a racing boat, it is a beginners boat, a boat for people to learn how to sail on. Don't compare it to a racing boat because it is not a designed as a racing boat.
I took the ARC17 to the Tradewinds race for people to SEE IT. The boat has no US Sailing PN. It is a new boat. The best shot at a PN for the Tradewinds Race only was to use the SC17 PN and make adjustments for the things that are different between the SC17 and ARC17, boat width and sail plan. For the next race it sails in, I think a better number would be to take the last four heats of the Tradewinds and reverse engineer a PN for the ARC17 and calculate what the PN needed to be to make the ARC17 tie on corrected time with each one of the other boats in these heats. Then throw out the odviously high numbers, if there are any, and average the best of the low numbers. This should be a more correct PN number for the boat. This is how you get a correct PN for a new boat. This is the process in action.
You are right, Sam, there is no ARC17 class at this time. There are two boats in the whole world. You have to start a new class somewhere. When the class grows to ten boats or so, an association will be formed.
There is an ARC22 class organization with officers and race schedule and class rules etc. Every 22 that has been sold came with a book of class rules to keep the boat/sails etc class legal. A US National Championship Regatta is scheduled for this year. All SC and ARC boats are welcome.
The class has a web site with forums, etc.
All ARC products have class rules for platform geometry, rigging geometry, max sail sizes, etc.
I hope you are feeling better real soon, Sam.
Bill
Steve,
What I find really interesting is the "cultural" difference between sailing cultures on the various continent..
(My opinion)..
We in Au have been unfortunately been invaded by the heavy plastic under powered under achieving "international" classes..
My father learnt to sail as bailer boy on 6, 8, 10 and 32 foot skiffs.. If you can have a look at the sail areas they used to put up..Then graduated to skippering a home built 6 footer.. (at 13).. My first was a VJ.. 11'6 (just under 3.5 meters) sharpie planing hull.. Sort-of like a pointed bowed hard chined scow, 3'6 wide at the gunwales, and to keep her upright twin planks (the class was designed before trapezes were invented).. 45kg weight limit.. 120? sq feet working sail area with a assymetric kite.. chine to gunwale height 200 mm.. The races started at 1:30 pm.. My local pond has a summer breeze of 22 knots average so many days we started in conditions where foam was blowing off the chop.. On those days I just wore 6 wool jumpers rather than the normal 3.. I was 13 weighed 5 1/2 stone (35kg) I still remember the day we put the kite up and sailed over the Australian 14 skiff champ on a shy reach.. To be honest it was in the days before a wind upper restriction applied.. The hull was out from just behind the centreplate and only 1/3 of the width of the hull.. Scary yes but exhilerating.. I was hooked!!!
A few years ago I unfortunately took my son down to his first sailing experience.. So he went out on an opti... and came back bored.. Now getting him near a boat is difficult as he considers sailing is boring.. When my arm is ok I hope to take him out on the F16 and show him it can make his young heart skip (he is 10).. The first impression is important and takes a lot of good experiences to overcome the first..
My point after the ramble.. Wish I had taken my son out on an higher preformanced boat like an ARC17 (not that I have seen one) rather than let him see an opti..
Weren't the first classes open boxed classes?... A, B, C and D..
Just wondering which new class is "High Tech"?
Nomex honeycomb carbon epoxy was used to build boats in the 80s.. So its now what 20 years old as a technology..
Hi Stewart
I agree with you…the building materials/method of construction is twenty years old…yet they market it as something new and improved…you will notice in my earlier post I said some of the new boats/classes are marketed as High Tech/High Performance…I didn’t say whether they “were” actually High Tech/High Performance…:) that remains to be seen...and when a 20 + year old boardless beach cat design comes out of mothballs with a new sail plan and sails that well against current racing cats it calls a lot of things into question beyond just the PN of the ARC 17...
Bob
This thread was originally a question about planing hull cats vs. displacement hull cats with spinakkers, but was quickly hijacked to become an advert for Bill`s new boat, while at the same time gave Bill an opportunity to discredit designers of other boats :Quote from Bill Roberts, after hijacking this thread to turn it into an advert for his products :'"All boats that fly spinnakers have lee helm". Only boat designs that place the daggerboard in the classical position, approximately at the shroud chainplate, have lee helm with the spinnaker up. This is a system design that has ignored the spinnaker during the design phase of the boat development and the designer/manufacturer expects the sailing public to put up with it. There is a sail/boat design system that does take this CE migration into account. The design system is called "shared lift" and it is incorporated into ARC products. It has to do with shifting the board location forward so that the CE with spin up cannot get in front of the board. Then down sizing the board and up sizing the rudder so that the shared lift between the board and rudder is in the correct effective location for sailing the boat as sloop.'
That`s wonderful news. He then goes on to tell us how any beach cat that was designed by anyone else has terrible tendencies to kill, maim & frighten the hell out of anyone, while his boats are built with only SAFETY in mind. I hope he has good legal counsel, from what I understand you can get sued in the US for looking at someone funny, never mind calling them an irresponsible yacht designer : "I see nothing but praise for the H16 on this forum. In West Palm Beach, Florida two sailors have lost their lives because of the unsafe characteristics, easy pitchpole tendency, of the H16 design. It is the same for everyone sailing a H16 so, what the heck." Bill, I suggest you write to some US sailing magazines & ask them if they`ll publish that for you, then wait for Hobie`s lawyers to start calling you. It must have been a HUGE pitchpole, if that was the official cause of death. Personally I`d rather be caught out on a H16 in a storm than a 17ft boat with more sail area than it can cope with.
Yes, there are more than one way to make a cat fast - one method is to improve on construction methods to make the boat stronger & lighter, and put on a reasonable sailplan that is manageable in up to 25knots of wind, probably the upper design limit for most beach cats (oh, except for the SC range of course). The other method is to use cheap construction methods, overbuild them to make sure they`re strong, don`t worry about the weight too much, you can always load up the sail area & widen the boat to compensate.
Just don`t ask me for help dragging it up the beach.
I still can`t figure out how some people believe that a 17ft boat with more sail area than a F18 can be regarded as a beginner`s boat. I`m really impressed with the idea that someone actually built the thing, it seems horribly overpowered to me. The only SC boat I`ve seen is a Supercat 20, took the guys 2 days to rig it, was heavy as a speedboat, and once capsized it had a complicated stay-lengthening device to help right it.It took so long to manipulate that they went turtle, and needed a rescue boat`s assistance. It never beat a Tornado over the line at our club, old Tornado with old rig, one trapeze and heavy by today`s standards. Perhaps the owners never read the manual.
I also understand that the "new" 17ft design is not a re-hash of the old SC17 hull shape, but is in fact a new design, which is what lead me to ask why design something new which doesn`t fit into any of the formula classes - If this was done it would go a long way to getting more growth in the formula classes in the US, which would benefit everyone. I`m absolutely amazed that anyone would buy a NEW boat that doesn`t offer the ability of inclusion in one of the Formula classes. I know that the Formula classes are not huge in the US, but then if the US designers are purposefully avoiding them it`s no wonder.
I believe that Wouter has made the only sensible comments on the original question in this thread, and summed things up quite nicely with this :
The whole point comes down to the fact wether the ARC products are fast because of efficiency or because of the huge rigs they feature. The problem here is that without having a really comparable design using the "normal setup", it's hard (if not impossible?) to tell wether any speed increase is the result of superior efficiency or just the result of having a bigger engine.
I`ts good that Bill designs boats that are different, challenge the "norm" and don`t conform to formula rules. As he says, they aren`t intended for racing, except against themselves. Sounds like his ideals are not so different from those he criticizes the most.
Cheers
Steve
BRAVO!
Hi Eric,
All it takes is money. The tooling that Aquarius has was built back in the 1980s and that is all there is. You guys stand around and say "build a new boat of this or that size and the world will beat a path to your door". Been there and done that and it doesn't work. The telescoping SC20 won the OAK Regatta in 1981 by a wide margin over all the California hot dogs. The SC20 had a demonstrated and substantiated PN of 62 and the Tornado had a PN of 64 in the early and mid 1980s. The tall rig 20 was 60.I gave the sailing public what they "said" they wanted (a boat faster than the Tornado) and I built it and then they didn't want it afterall. A couple of hunderd boats were sold over ten years; not enough to keep a boat company in business. I lost a nice retirement building the SC product line. The SC 17 is the only boat I designed that made any money/profit. I have some sensitive scar tissue, Eric. Understand now why there is an ARC17 effort?
Good Sailing,
Bill
Good Sailing,
Bill
Hi Jake,
All of the SC design work and tooling building was done back in the late 1970s and early 1980s. This is long before there were any box rule design design classes.
When I was doing my bech cat design work, the contest was about speed not efficiency.
But speaking of efficiency: The RC30 has a PN of 54, same as a Formula 40. The RC30 is 30ft long vs 40ft for the F40. A new carbon RC30 with trailer, beach wheels, an extra siut of sails, spare battens, outboard motor, life jackets, trapeze belts, gloves, tool box and hand tools, anchor and line, lights and navigation charts, everything one could possibly need for the boat costs less than $100,000. A new F40 costs over a million dollars. Now, how's that for efficiency, Jake?
Bill
PS You Applaud the M20. I do too. The unique thing about the M20 is its weight, 150 pounds less than a Tornado or 200 pounds less than an I20 or N6.0 and you do not mention that. Why not? Do you have any idea what it would cost to take 200 pounds off the weight of an I20 or N6.0?
Hi Wouter,
I appreciate your compliments and good wishes. This is quite a change. I can't help but think you have had something special to eat or drink just before you wrote the above letter. Your mom must have fixed you your favorite dinner.
Good luck with the F16 class.
Bill
I understand, Bill. I just wonder, as others do, why you have not focused your efforts and resources to build a boat to compete against a more popular design. Using the same box or "formula" would for sure highlight your design innovations. Don't get me wrong, I think the ARC 17 is an excellent design, innovative in design of the controls and now I have seen that is very fast in moderate winds.There is just no boat to compare to to ferret out the strenghts and weaknesses. If I had the cash I would look at the Arc 21 0r 22 in a heartbeat, again, great innovations and simplicity.
I appreciate the fact that you have devoted your time, talent and treasure in the pursuit of your interests, not many people can say they had the balls to do it.
NOTE: Another poster threw down the gauntlet, I just stirred the pot.
Ahh Bill,
Not much has changed. I'm really not hung up on the ARC-17. I expect it to be a great boat and would love to see more of them on the water. I'm still comfortable with you as well; next time I see any of the SC in NL again I will again take their picture and send it to you (like I did a Texel) and convey the regards of their crews.
The thing that got me going was the "story" around the ARC-17 design and its quite implied dissing of several other designers and related designs.
Really you are not the only designer who has experimented on cats or taken measurements. Nor are you the only one confronted with the issues around a spinnaker. You solved it in your way the others in their way. The real life results are different from what was stated as undeniable truth. Therefor the theoretical model you used was not describing the reality accurately. It is by all means a "feels right" model but inaccurate none the less.
Without hard proof the views expressed become dogmatic. Hence the gauntlet thing.
Now on my my part I haven't quite worked out why it behaves differently but that is mostly because of lack of effort. When something is not a problem than I'm less willing to explain why it is not a problem. I tend to accept it and move on.
Factors that may result in the different behaviour :
-1- Spi is fitted asymmetrically to the boat. The normal rig pushed the boat along almost along the centreline. The Spinaker is to the lee of this and thus its lift factor will induce a weatherhelm effect as well.
-2- The conponent of the total lift force that lies along the centreline may be several times greater than the component perpendicular to the centreline. It may be that
Leehelm component - weather helm component = lever 1 * force perpendicular to centreline - lever 2 * force along centreline = close to 0 or very small.
To give another example. Yachts without a spi have greater weatherhelm on deep downwind sailing legs than on upwind legs. With spinnaker they balance out again. A different setup I agree but it shows that there is more to the system than the simplied model that was used in this thread.
This is my last post in this thread.
Now, indeed Fair winds to you and I'm looking forward to more race results. If anything it helps to improve on the understanding we both have on the subject.
Wouter
Hi Wout -Bill -John and all ,-great thread ,-just sat back and read others on this one though very interested ,
like John P posts and Bill,s as active designers of existing cats in the marketplace .
Wout your perspective is from a main objective and goal of building a Formula class {worthy endeavor } but in discussions it often makes you {talk past another} as they say . 
An interesting project > I have a SC 15 that I,d like to modify w spin {experimented a little already with one on the sc } and have it comply with F-16 rules for future racing ,--I,m not sure if I,ll add boards or a smaller molded in skeg or just use more rake and load up the large rudders more on this non boarded design .
I may add a little foam expoxy v shaped {for rudder movement} fairing plate off the stern to make it a full 16 ft .
The problem earlier on migrating CE forward with the spin up is the problem I,ll face in adding the spin .
In looking at a side view diagram of any cat -
http:/
The CLR -{area of underwater profile inc boards & rudders}
has been designed in older non spin cats without consideration of the spin area which when raised moves the CE way forward .
Most racing sailors have found that when you rake the mast aft more under spin the better your speed and handling characteristics. In effect moving the total CE back -
but how much ?
The spin pole is a certain distance from the bows per rules ,-the mast base in located the same ,-an extreme amount of added or extreme mast rake may be a meter or little more ,--thats all .
Draw this out on a particular design with accurate sail area mast height and general specifications in the normal position {without spin} and with extreme mast rake and spin area in calculation of CE to CLR .
Spin are av equal to or larger than the main &jib area
spin tacked out forward on the spin pole.
The CE evan with extreme rake is still way ahead of the CLR , tHIS NECCESITATES the moving of the board forward ,near or at front crossbeam location as noted , for spin boats .
One other interesting option would be an evan more forward located smaller angled lifting foil or skeg to change the CLR to CE .
for other readers -
CLR is Center of Lateral Resistance =side view underwater profile under sail and center of area inc boards foils and rudders .
C E is the Center of Effort = center of areas of the sail plan -main -main jib -or main jib spin combinations .
Generally the CLR leads the CE by a small percent ,-allowing for mast effects and wanting some weather helm designed in or nearly nuetral helm .
The forward lifting canted foil nearer the bow to balance the spin CE would create added drag , offset by its ability to lift at higher speed and balance the helm under spin.
In upwind mode this would load the rudders evan more ,
requiring a smaller aft board as well ,-this type of for and aft board configuration is very versitile under many different sail combinations ,--thinking of larger cats -reefing jibs and mains ,-stormjibsails,-and cats with adjustable rigs ,- etc .
An ideal cat design would have an ajustable mast rake ability under sail ,-forward position in normal windstrengths upwind ,--then raked back to an extreme downwind .
The 60 tris have adjustable rigs ,-the first I saw it on beach cats was the 87 Worrell 1000 ,-It was Reg Whites son on a 12 beam Hurricane that had attached a 3 to one block system and cleat at the base of all stays with about 6 ft of adjustment ,-it could be raked back ,--and also to windward a little if desired . 
Small inward canted forward lifting foils particularly for 16 ft cats that counteract forward forces -used on the 60 tris so well to carry their huge sail plans ,may be the ideal development for them allowing them to be pressed much harder in high wind speed conditions .
fun to theoretically go through design options and potential variation to explore .
good winds
Seeker San,
So what do your kids hold on to on the 17? Shroud, or hiking straps? Most people think a begginner boat would be like a hobie wave or something with a lip that you can grab on to.
There really aren't any cats that don't dive the bows when pushed hard enough. I just think supercats sail bow down when powered up. Many factors contribute to this. Even if they are hard to pictchpole it still isn't very fast to have the whole hull under water. In the picture that i posted before, the supercat is working very hard to keep the bows up while we are leaning forward. We started at the same time as i recall and we are on the same downwind leg of the race. pretty shure that is Bill at the helm of the SC.
I personally like to sail a boat bows up or flat, not bows down. Wouldn't feel comfortable at high speed reaching with the bows down to get shared lift. Also i take offense will Bill's comment that v in the tail is improper design. So what if it makes a boat harder to tack. Even Tornados only make 1 tack to the A mark if possible. V in the tail and bows up are good in the waves.
In answer to your question about me sailing a SC17, actually, i worked at Boston Whaler SuperCat untill i was fired for not working on Saturday in spite of the fact that they had paid my expenses to race in Miami that weekend. Corp. b.s. -one hand didn't know what the other was doing. 1980 or 81...
Bill's best design was the captive mast step-cudos there, the boats themselves don't do it for me. The round top just funnels the spray into your face and isn't worth it.
The big Trimaran guys seem to use a similar hull for the ammas though.
In any case it's a good thing that you get your kids out there cat sailing in the ocean.
PS. there could be some errors here because the 80's were a while ago.