Les,

Thanks for the info on your boards being up on your I-17R

Works that way for me to (..in my winds)

I always wondered, again, I am a driver,..is it possible for the entire I series, ( I-17, I-18 and I-20),..to have the same daggarboard ?

Builders, Designers,...what do you think?

Bruce
St. Croxi

Hi Harkan,

Thanks.

You said:
>>The hull needs to be strong where the centerboard well is located

I'd have to agree... except that the hull is already strong where the well is already placed in the aft position on most cats and since the forward position would be close to the main beam, I would guess its already pretty strong there as well so although it might need some reinforcing it shouldn't be a major obstacle...

You also said:
>>Two centerboard wells on each hull means more weight

I'd have to agree... except on long legs of a course or cruise the relatively small amount of additional weight that would be introduced might be easily offset by modestly increased efficiency and drag reduction not to mention that a less fatigued skipper might end up being a better skipper when at the helm for extended periods in these conditions further compensating for slightly increased weight...

And finally you said:
>> The empty well will create turbulence.

I'd have to agree... except in my original post I said:
>> you could use "rubber slats" to automatically seal the bottom of the unused CB trunks to keep flow non-turbulent there as they do on retractable CB windsurf boards

I don't know if you're familiar with this approach but it works very well - two thin but tough sheets of rubber running along the length of the centerboard well, each attached along the outside edge as well as fore and aft, "kissing" in the midline. When the board is pushed down, the rubber parts and allows free sliding (also gives just the right amount of friction to hold the board where you want it) but when the board is raised, the slats close and present a very flush surface to the water minimizing any turbulence.

Jerry

Hi Bruce,
I don't think so. Board area usually varies directly with sail area. They might use the same board section and vary imersed depth with sail area. This should work, but I don't think they would literally use the same board on three boats with different sail areas.
Bill

Lets try again Bill.

>All SCs were sold without spinnakers. That was before 1992, 1978 through 1991. In 1992 the product name was changed to ARC products and spinnakers and self tacking jibs etc became an option or standard on all products, the 22, the 27 and the 30. See the Aquarius-Sail.com web site for this information.
SE- You need to talk to the people at Aquarius Bill.
According to their website, as of five minutes ago, NO Aquarius boats are sold with a standard spinnaker.

>These products were/are designed with spinnakers.
SE- Then why are they sold with out spins?

>I'm sorry I forgot, the 22 also has the CB trunk located right behind the main beam to prevent lee helm with spinnaker up.
SE- So the non-spin SC 20 had the boards directly behind the front crossbar? Are the ARC 22 boards different from the SC 20 boards?

>I am saying that moving the CB forward is a better way to trim a boat out with spinnaker than raking the mast back which leaves the rudder overloaded and the CB underloaded sailing to windward without spinnaker. The boat will sail to windward like this but the induced drag from the CB and rudder is greater than it could be. The boat is out of trim sloop rigged.
SE- Why did you intentionally design many of the Supercat and SC boats "out of trim".

>A boat with centrboards moved forward to accomodate the forward migration of sail center of effort due to the spinnaker and downsized boards to match the smaller side load they now are expozed to in this new forward location and upsized rudders to match the new increased side load they are exposed to due to the forward located centerboard HAS THE SAME CENTER OF LATERAL RESISTANCE as the boats original CB/rudder arrangement. The advantages here are: 1) that the centerboard is so far forward that the sail CE with spinnaker up cannot get in front of the centerboard and cause lee helm. 2) With spinnaker down the centerboard and rudder are sized to match the loads they are exposed to and this results in minimum induced drag from the CB and rudder, a faster boat to windward.
SE- Which boat are you referring to, The ARC 22,27,30 or the ARC 21?

> At the recent Tradewinds Regatta I sailed an ARC 17 against several other boats for my first time in 25 years.
SE- The ARC 17 came out in 2003 and you raced a number of times last year on ARCs.

We sailed poorly, went three times around the long course when I should have sailed two times around the short course, in the first heat. Then on Sunday my crew, who had never sailed on the boat or with a spinaker before, thought we shouldn't try the spinnaker in the 20 knot winds so we didn't. We still won the open class on corrected time and did finish a couple of heats first boat across the finish line. Our assigned PN was 70.2. That number is coming down as a data base is developed for the ARC 17 with spinnaker.
SE- Such a sad story.
Speaking of the ARC 17, someone was asking about racing an ARC 17 under iF18.
This begs the question, why did you come out with an ARC 17 instead of an ARC 18, built to iF18 Class rules?
Or an ARC 21 instead of an ARC 20 built to F20 Class rules?
Why do you and Aquarius continue to hide from Class competition?
Do you actually think you will sell more oddball ARC 17s than you would sell ARC F18s?
Well, if ARC F18s lost every race then you probably wouldn't sell many.

What about an ARC F18HT? You brag about “state of the art” construction.

iF18 Class - 63.5 dPN, 397lbs, 183sf main, 44.7 jib, 226sf spin
ARC 17 - 68.3 dPN, 350lbs±, 206sf main, 51.0 jib, 290sf spin
F18HT - 60.0 dPN, 287lbs, 215sf main, no jib, 215sf spin

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.

The ARC 17 has a sail area(sf) to weight(lbs) ratio of 1.563, the F18HT is 1.498, the F18 is 1.143.
The ARC 17 has a higher “horsepower” to weight ratio than the F18HT and iF18 and yet it competes with a dPN of 70.3.
What do you prove when you "win" a regatta with a totally bogus handicap number?


I repeat this question:
> P.S. You never have told us the name of the other "boardless 17foot beachcat" that yours is so much better and faster than.

You are looking to find a solution for a problem that doesn't exist. Bill says that it does exist on non ARC boats like I-17, I-20 and Stealth while various I-17, Stealth, I-20 etc sailors and designers have said that it doesn't.

It now all comes down to who you believe most.

I had enough of the shared lift farytale. I think John Pierce said it right, we are really talking about the same thing here.

Loading up the rudders by mast rake or loading up the rudders by placing the daggerboards forward both lead to the same end result.

>I was curious if two wells would work well for cruising, recreational sailing, and long distance racing where it might >offer a very light touch both upwind and downwind for long legs avoiding any strain on the skipper

You have begun to buy into the Fairytale. Don't you see ? Why can you balances the rudders to remove the feel of the big weather helm that is part of "shared lift principle" as a direct result of the board placement but can't use the same principle of balanced rudders to relieve the stain on the skippers of other boats as well.

There is really no difference here. Just smoke and mirrors.

Wouter

Wouter,

Thanks for your input. Maybe I am missing something so help me see the light:

You said:
>> Loading up the rudders by mast rake or loading up the rudders by placing the daggerboards forward both lead to the same end result.

But I was talking about placing the boards back under cat rigged/sloop and forward under spi. It was my understanding (and maybe I'm wrong here), that by doing this one would NOT be loading up the rudder either upwind or downwind. If this is true, wouldn't an unloaded (or minimally loaded) rudder be more efficient? Less drag? Less likely to stall? Now, if unloaded rudders don't offer any benefit or if really matching CE/CLR doesn't unload the rudders, then that is what I needed to know regarding why this approach would have no value.

You also said:
>> You have begun to buy into the Fairytale. Don't you see ? Why can you balances the rudders to remove the feel of the big weather helm that is part of "shared lift principle" as a direct result of the board placement but can't use the same principle of balanced rudders to relieve the stain on the skippers of other boats as well.

It was my assumption that if the CB is placed properly for each sail configuration to balance CE/CLR then you wouldn't need to balance/rake the rudder for either big weather helm or big lee helm. This sounds more efficient to me; if it's not really more efficient, then that is what I wanted to know!

Finally, please understand, I'm not disputing that the current approach "doesn't work" - in fact it works quite well. Does that mean it can't work slightly better? That's what I am trying to understand. Fortunately you guys have far more experience than I!

Jerry

Jerry

Let's see if we can put this one to bed.

1.) Everyone agrees that some weather helm helps boats performance to windward, therefor it is more efficient. Lets be clear about this we are probably talking about less than 1 % gain.

2.)This weather helm can be made so that it does not create a load on the tiller by balancing the rudder

3.) when the spinnaker goes up the centre of effort goes forward, so the weather helm will go, and can produce lee helm,

4.) Again a balanced rudder will make it so that you do not feel much of this load.

5.) having two centreboard slots will lose much more than any gain, since the only gain is removal of the lee helm downwind, and the loss due to this is microscopic. But the losses are:

turbulence from the slot:greater than 2%, slot gaskets work well with rotating c/boards, jam with daggers,

time taken to change boards, loss of at least 10 seconds each change,

Extra expense, you could spend the money elsewhere where it would make genuine gains.

Hope this helps.

The point is skiffs are unstable.. Thus skiffies are more attuned (as are their rigs) to the weather.. Make a slip, miss a gust or lull and you swim.. As you seem to agree this isnt the case for cats.

As for skill levels..
Could a skiffie get on a tornado and win.. Hmmm... well F& B are flipping good.. It will take any crew some years to develop the skills to match them..
But before F&B reign on the Australian scene.. A couple of skiffies did get on a T and won for almost a decade.. Including Au T olympic selection and either a 3 or 4th at the Olympics.. Dont know what that means but...

Oppsss off point.. Skiffies enjoy the challenge of keeping their crafts upright and they have the best ride downhill.. Even if a cat may be faster than all but the 18teen..

Stewart

Thanks for questioning the SC-17 PN#. I sailed open class on my stock H-20, I was first over the line 4 0r 5 times out of 8 races and still got clobbered on PN. The course was relatively short but the format was great. The Arc 17 was very fast, I was usually on 20-30 seconds ahead at the A mark. It is much faster than the assigned 70 #. I was suprised that it won.

It is a beautiful boat, full of innovation and goodies, sqaretopm Main, spin, selftacking jib, trick main traveler set up jeez what did I miss.

>>I was first over the line 4 0r 5 times out of 8 races

You were first over the line in 3 out 8 races.

See the results attached

Wouter

What happened in race 2 the differences between the boats are way to big for such a short course.

Wouter

I did some slacking on the 49-er in my other post BUT I wouldn't want to go without one.

I really like sailing the skiff but for totally different reason why I like sailing a cat. With the Skiff the joy is in getting the handling right and show of your skill by making it look easy. (Still a long way off)

With a cat it is the power and the simple form of racing. Seastate, winds it doesn't matter with a cat you can race all in all conditions and have a bloody good fight for hours on end.

With a skiff you can drain yourself within 30 minutes and go swimming because you can't keep the level of concentration up.

Skiff rigs are an interesting topic in their own right, but are optimized for the limitations that are encountered on a skiff. This probably makes application of such a rig on a cat less optimal.

Sail both enjoy both.

Thanks for the heads up on the skiff 12,14,16 rules

Wouter

Hi Sam,
We have one gaint communications problem.
As to spinnakers and ARC boats: Spinnakers and spinnaker poles and all the gear, blocks,ropes, etc, you need to go with it are an option on all ARC boats. Some ARC22s and most RC27s and 30s are sold as non racing boats and the buyers don't want spinnakers, they daysail the boats, so the spinnaker is left as an option. In US Sailing PNs the 21, the 22, the 27 and 30 are all rated with spinnaker.
>All of these boats are designed with spinnakers and sold both with and without spinnakers.
>The old SC20, 1978 thru 1991, had the CB back by the shroud chainplate, same as other 20 ft cats.
The old SC20 boards and the new ARC22 boards are the same size. The SC20 had 275 sqft of sail area on a 33 ft mast and the ARC 22 has 350 sqft of sail area on a 38.5 ft mast. The sail area is up by 27% on the 22 and the boards are located forward just behind the main beam where they are exposed to 27% less side force from the sails. Therefore in effect the 22 boards are downsized 27% per sqft of sail area relative to the old 20 installation. The boards feel the same side force on the 22 as on the 20 even though the 22 sailplan is 27% larger.
SE- Why did you intentionally design many of the Supercat and SC boats "out of trim".
> The SC boats and other centerboard cats, slop rigged, are in trim when they run a normal amount of mast rake like 5 degrees or so. When the top of the mast is raked back an additional 3 to 4ft to trim the boat out with spinnaker and then you sail this larger mast rake to windward, the boat is out of trim.
SE- Which boat are you referring to, The ARC 22,27,30 or the ARC 21?
> Each one of them, Sam. All of these boats have the CB right behind the main beam.
SE- The ARC 17 came out in 2003 and you raced a number of times last year on ARCs.
> An ARC17 was on the water in Mn undergoing development in 2003. I never set foot on the boat until it was in Florida a couple of weeks before the Tradewinds Jan. 2004. I raced/crewed on an RC30 in 2003.
SE- Such a sad story.
> Right, Sam. There was another communications problem. The race comittee held up a race course sign with an L on it. Some sailors in the open class took that to mean sail the long course. As it turned out it ment sail the shorter course.
> Sam, the ARC17 is a beach boat, a beginners boat, a boat without boards. It is not a performance 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.
>As to your question about an ARC 20: If you or anyone wants an ARC20, it can be built in a heartbeat. Use the 22 tooling and move the transom forward 2ft. Then you have a 20ft boat built for ocean racing. The tall elliptical bows are forgiving in big waves and or a near pitchpole situation. (Look at the picture of the SC20 during the Steeplechase race. The foredeck is underwater and the boat is ripping. The sailors are in their normal positions. You don't see rear ends and elbows as the sailors scramble for the back of the boat. These guys know that this hull design is not in difficulty at this point.) Building a 20 in the 22 tooling would place the mast 2ft aft of the hull mid point. Again moving the CG further aft and allowing the sailors to apply more horsepower, drive the boat harder, while reaching downwind with chute. In 1980 the SCs had a simple on the water mainsail reefing system that could be employed in 5 minutes. This would allow a high powered boat to depower quickly on the water. A long distance race ocean race winner is sitting on the shelf up there in Mn.
SE Why do you and Aquarius continue to hide from Class competition?
The tooling for the 22, 27 and 30 were all built before there was any of this Formula class stuff. In about 1988 when the 22 was designed, other builders were building boats longer than 20ft. There was the H21 which was 21.5ft long and Stiletto was building a 23ft boat. I did a 22ft boat to sort of split the difference. As it turned out the H21 and Stiletto were slower than some 20ft boats. Only the 22 continued the progression of faster boats as they got larger. The 22 has set the chinning bar. Why won't anyone else step up to the 22. Everyone else, the competition, has retreated.
> As to your last comments: You probably did not know the 17 is a boardless beach cat for the beginning sailor. It is not aimed at performance. It is a simple boat, a very safe boat with tall bows and righting system and the rig is totally flexible to the owners desires. You can buy the boat as a one person boat. If things change and you want to sail with two people, no problem. Add the self tacking jib. When you get good and are feeling your oats, add the spinnaker, no problem again. You don't have to buy a new boat everytime your circumstances change.
Good Sailing, Sam
Bill

You've got it right, Carl and those boys from down under have known about this and incorporated it into their skiffs at least 50 years ago. We're just learning.
Bill

Just to (hopefully) clarify, it helps to realize from a drag perspective, all things being equal and ideal, that the optimum is two boards (1 rudder + 1 dagger) of the exact same size, at the same angle of attack.
Also, this necessitates the center of effort intersecting the middle of a line directly between the two boards. The further apart the two boards, the less effect the shift in CE has, the more "balanced" the boat. Voila.
Of course this all gets screwed up by the hull and daggerboard being locked together, the board being adjustable in area (unfortunately proportioned to aspect ratio), and the rudder being of fixed area, but adjustable in attack angle, and wind strengths varying.
Humbly Submitted by a Talkerabouter.

Sorry guys, I stand corrected, Wouter is correct. However, look at race one...The Dart seems to have been sailing the inside(yellow)course. There was also alot of confusion revolving aroung the general recal of the I-20's and susequent course change on the open class restart. As Bill noted earlier, we all seemed to have sailed an extra lap in at least one race.

Wouter, I still maintain my earlier comments regarding the ARC 17 PN #.. Bill, nothing personal, that boat was fast. Had you had experienced crew and flown the chute down wind the PN # would be open to even more scrutiny. You are extremely intelligent, you know the number needs work. Benefit from it while you can....
I am still hooked on that trick traveler and straifgt jib track.....

Hi Eric,
As you know I have nothing to do with the level of any boats' PN. When a boat starts out new, the initial PN is a guess. The ARC17 PN was based on the SC17 and adjusted for square top main and spinnaker and boat width. At Tradewinds Rick did the calculations. He used a spinnaker adjustment factor of 0.972. I think US Sailing uses 0.96 but, he is the boss at Tradewinds. Anyway, race data will bring it in where it belongs quickly. Tom just needs to sell a few and get them out there racing.
Good Sailing,
Bill

Thanks, Jonn.

Now THAT was what I wanted to know (expecially the magnitude contribibuted by each element)!

Jerry

Bill,
I know..Perhaps this brewhaha with "H" will bring some new Arcs into NAMSA. Let me know if any 20' to 22' "used" Arc become available. I think a new one is out of reach for me but I love the set up, really simple and clean.

>It now all comes down to who you believe most. <
>I had enough of the shared lift farytale. I think John Pierce said it right, we are really talking about the same thing here.<

You MISPELLED farytale (fairytale), your getting as bad as Bill, in the drama department. So you like to use drama, too?



>Loading up the rudders by mast rake or loading up the rudders by placing the
daggerboards forward both lead to the same end result.<

I disagree. Same result, but from my experience there is a difference you may NOT have considered (luff perpendicular)? There is a difference in acceleration, and top speed is basically the same (hull speed). Over ten years of R/C sailing mast rake (>5deg) has been slow accelerating out of tacks (& starts). Model boats normally tack on every shift, on average 6-12 per weather leg. So you gain 6-12 seconds which is all you need say if you are match racing. The model boat is extremely sensitive to adjustments of CE and is done by moving the mast base 1/4"-1/2" fore or aft, NOT mast rake. I don't see America's Cup boats using a huge amount of mast rake (>5deg) for tacking, so I believe scaling this up to larger boats applies? In a light wind with moderate chop where acceleration and power is needed the boat with the mast rake (>5 deg) would loose.





>There is really no difference here. Just smoke and mirrors.<
Is this a professional comment? I'm SUPPRISED to read a comment such as this coming from a person I regarded.