C Class Challenge with a twist

There are six rules that define a C Class yacht. In essence, they are (with a slight change):

1) It must be a catamaran,trimaran, monohull or any combination thereof.
2) It must have a crew of 2

3) It must not exceed 25’ in length

4) It must not exceed 14’ in beam

5) It may have up to 300 sq feet of sail area (27.90 M^2)

6) It must have a sail number and the class symbol
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Just for the hell of it I wanted to see what a "monofoiler" built to the C Class rules would look like-numbers wise. I included trimarans because this thing would have very small pods-somewhere between 160 and 350 lb. of buoyancy. Just to keep it upright when not sailing-and I wanted it legal w/o an arguement.
C Class Monotri
-LOA 25',hull L/B 18-20/1
-Beam 14' incl. carb racks and pods
-SA-300sq.ft. with a CE just below 75% of a C Class Cat/ Problem: designing it with a high enough lift coeficient at a lower aspect ratio.
- main hull beam 1.25'
- Weight Targets: Hull, foils,racks--120lb
Rig- 140lb
All up boat weight:--------- 260lb
Foil Loading@ 80% on mainfoil: 158lb. per sq.ft.
Mainfoil area: 2.93 sq.ft.(take off profile same as Moth-or better with variable geometry main foil)
Note: to eliminate unecessary flap movement caused by wand averaging in chop manual control of the main foil flap would be tried-no wand)
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Rig has to be shorter than the cat version because Monotri RM(including Veal Heel) is only 59% of the cat.
Other comparisons:
W/SA-Cat: 2.26lb (sail loading) Monotri: 1.93lb(sail loading)
Target weight would keep Monotri 100lb lighter than a Cat.
SA/WS ratio flying would be- much better than the cat-in fact then Monotri would have only 30% of the wetted surface of the cat with the cat flying a hull.
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Could it be done? Could it win?
If a legit challenge emerged could/would the rules be changed for a trial run that counted?



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C Class (monotri) Challenge

Steve Clark is one of the great innovators in sailing; still I was suprised to get this answer from him-which I greatly appreciate(from the DA thread):

"Doug, Our first rule is that the boat has to be a catamaran.
Unnecessary type forming? perhaps, but I would say that opening the rule to other configurations would be a fundamental change, not a minor change.
So the short answer is no.
There are many longer answers that would have to do with making more advanced calculations and studies of the speed potential of your proposed boat.
If you build such a beat, it will be very interesting to sail against it. We can't call it the I4C but that doesn't mean that an alternate challenge couldn't be made.
Build it and I will race against you.
SHC



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Beatings will continue until morale improves."
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Thats almost an offer I cannot refuse.......

 

I guess that is what a lot of us are saying Doug. Time to build it not talk about it. That is what I am doing to my modified Raptor. It looks good on paper. Now it is time to finish all the mod's and see how it works. I had to work my *** off to pay for the materials and new sail. But I worked all winter on it and is almost ready to fly.

 

C Class MonoTri

Oh? This is a long way from being built but thanks to Steve and Magnus I'm inspired to look a lot closer than I have so far. The preliminary numbers are real encouraging but thats about it for now. I'm already in the middle of building my own boat, Ed, and this thing needs a lot more study before anything will happen.
But it sure seems to have some potential.....

 

Yes I know. I try to only take on one thing at a time. I do my best at design with whatever input I can find. Then there is a point where you just have to do it to see where you are. It might sail great or you just wasted a enormous amount of time and energy on something that looked good but just did not perform the way you thought. You and I have been there Doug. But from the construction and testing of your craft even if it did not work you now have new ideas that might make it work and the cycle repeats itself.

This is the way I am working out the bugs in my craft. Even Randy had ideas on the sailplan but with the rolling furling I needed it is a tricky design to come up with. Also going from 18' to 22' mast and 90 Sq Ft to 120 Sq Ft is going to be interesting to say the least.

I hope it works as I have a few bucks stuck into it.

But if you do not try in full scale you will never feel the pleasure if it works compared to a model.

I know since I had a homebuilt airplane for ten years that I logged 2150 hours in and Electric RC Sailplanes that I did for a few years.

 

C Class Cat vs C Class Monofoiler

These are the latest numbers I've come up with that compare a C Class Cat to a C Class Monofoiler:
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C Class Cat
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A) I found numbers for Invictus: 170kg(374lb) all up ;75kg(165lb) wing, 95kg(210lb) hull,cross beams, foils.
For the purposes of this comparision I reduced Invictus numbers to: 163.63kg(360lb) all up,72.18kg(158.8 lb.) wing,91.44kg(201lb)hull,cross,foils.
Note: on both boats crew CG figured at 1m(3.28') from side of boat(or racks):
Crew weight: 320lb(145.45kg)
B)RIGHTING MOMENT
Measured with boat just flying a hull:
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1) CB lee hull to boat CG: 6.5'(1.98m)(assume 1'(.3m) hull beam)=RA; 6.5 X 201=1306.5ft. lb/ 1.98 X 91.44=181.1kg/m
-------------------
2) CB lee hull to crew CG:6.5'(1.98m)+7'(2.13m)+3.28'(1m)=RA; 16.78' X 320lb=5369.6ft.lb / 5.11m X 145.45kg=743.3kg/m
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3) CB lee hull to wing CG: 5.635'(1.71m)=RA; 5.635 X 158.8= 894.83 ft.Lb. /1.72m X 72.18kg=124.2kg/m
========================
4)C Class Cat Total RM:= 7570ft.lb / 1049 kg/m

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C)----- Total weight: 320+360=680lb /145.45 kg+163.63=309.08
D) CE at 19'(5.79m)
E) Bethwaites Ratio: SCP/Total Weight
1)SCP= RM/ CE to CLR
a.-SCP=7570/19=398.42 // 1049/5.79=181.17
2)SCP/Total weight=398.42/ 680=58.6% // 181.17/309.08=58.6%
F) W/SA=2.26
++++++++++++++++++++++++++++++++++++++++++++++++++++
C Class Monofoiler
Note: crew =320lb(145.45kg)
A) --- Righting Moment
1) Veal Heel adds 1.5'(.457m) to righting arm
2) crew-1.5'(.457m)+7'(2.13m)+3.28'(1m)=RA; 11.78'X 320=3769.6 ft.lb // 3.587m X 145.45=521.73kg/m
3) hull +foils- 120lb X 1.5'=180ft.lb // 54.55kg X .457m=24.93kg/m
4) wing 140lb X 4.5= 630 ft.lb // 63.63kg X 1.37=87.18kg/m
5)C Class Monofoiler Total RM: 4579ft.lb// 633.84kg/m
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Total weight=320+260=580lb(263.64kg)
C) CE 13' (3.96m)
D) Bethwaites Ratio-SCP/Total Weight
1)SCP=RM/CE to CLR
a. 4579/13=352.2 // 633.84/3.96=160.06
2)SCP/Total Weight: 352.2/580=60.7%// 160.06/263.64=60.7%
E)W/SA=1.93
++++++++++++++++++++++++++++++++++++++
NOTE: if the hull weight goes up 50lb(22.7kg) then the ratio changes to 56.8%
-Veal Heel=17.7% of RM @ 15 degrees
- when on foils the Monofoiler has 1/3rd the wetted surface of the cat
close to the same off foils.
-In addition to a better SCP/Total Weight ratio the monofoiler weighs 100lb(45.45kg) less than the cat
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Precedent

Here is a picture(thanks to Kris Lore of Gougeons) of Victor T and incredibele "C Class(not legal)" trimaran by Meade Gougeon. 25' long and 18' wide and weighed only 300 pounds! In 1969!

 

Doug... Just one fairly obvious question and then, perhaps you can solve the dilemma.

If the Gougeon boat is illegal, how can it be a C Class anything?

A harbor tugboat is C Class illegal, as well. Should we be calling it a C Class effort gone awry? You know, just so we can lump the effort into a classier package of sorts?

Your C Class Challenge... with a twist, is also not going to make the inspection criteria. So, perhaps you should work on a different naming process for the unfortunate thing?

In fact, Unfortunate Thing is a quite good name for future reference, though I have already Trademarked and Registered that name and you'll play hell purchasing it. ;-)

 

C Class Cat vs C Class Monofoiler

UPDATE:

REVISION WITH THE RM FOR STEVE AND FREDO REFLECTED IN SCP/TOTAL WEIGHT
C Class Monofoiler vs C Class Catamaran--a first look

Back on track,again:
These are numbers I've come up with that compare a C Class Cat to a C Class Monofoiler:
================================
C Class Cat
-----
A. I found numbers for Invictus: 170kg(374lb) all up ;75kg(165lb) wing, 95kg(210lb) hull,cross beams, foils.
For the purposes of this comparision I reduced Invictus numbers to: 163.63kg(360lb) all up,72.18kg(158.8 lb.) wing,91.44kg(201lb)hull,cross,foils.
Note: on both boats crew CG figured at 1m(3.28') from side of boat(or racks):
Crew weight: 320lb(145.45kg)
B. RIGHTING MOMENT
Measured with boat just flying a hull:
--------------------
1) CB lee hull to boat CG: 6.5'(1.98m)(assume 1'(.3m) hull beam)=RA; 6.5 X 201=1306.5ft. lb/ 1.98 X 91.44=181.1kg/m
-------------------
2) CB lee hull to crew CG:6.5'(1.98m)+7'(2.13m)+3.28'(1m)=RA; 16.78' X 320lb=5369.6ft.lb / 5.11m X 145.45kg=743.3kg/m
-------------------
3) CB lee hull to wing CG: 5.635'(1.71m)=RA; 5.635 X 158.8= 894.83 ft.Lb. /1.72m X 72.18kg=124.2kg/m
========================
4)C Class Cat Total RM:= 7570ft.lb / 1049 kg/m

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C.----- Total weight: 320+360=680lb /145.45 kg+163.63=309.08
D. CE at 19'(5.79m)
E.
. Bethwaites Ratio: SCP/Total Weight
1)SCP= RM/ CE-CLR
a.-SCP=7570/19=398.42 // 1049/5.79=181.17
2)SCP/Total weight=398.42/ 680=58.6%// 181.17/309.08=58.6%
3) SCP/Total/WEIGHT(STEVE)=61.7%
4) SCP/TOTAL WEIGHT(FREDO)=61%

F. W/SA=2.26
W/SA(Steve)= 2.53
W/SA(FREDO)=2.46

++++++++++++++++++++++++++++++++++++++++++++++++++++
C Class Monofoiler
Note: crew =320lb(145.45kg)
A. --- Righting Moment
1) Veal Heel adds 1.5'(.457m) to righting arm
2) crew-1.5'(.457m)+7'(2.13m)+3.28'(1m)=RA; 11.78'X 320=3769.6 ft.lb // 3.587m X 145.45=521.73kg/m
3) hull +foils- 120lb X 1.5'=180ft.lb // 54.55kg X .457m=24.93kg/m
4) wing 140lb X 4.5= 630 ft.lb // 63.63kg X 1.37=87.18kg/m
5)C Class Monofoiler Total RM: 4579ft.lb// 633.84kg/m
--------------
B. Total weight=320+260=580lb(263.64kg)
C. CE 13' (3.96m)
D. Bethwaites Ratio-SCP/Total Weight
1)SCP=RM/CE-CLR
a. 4579/13=352.2 // 633.84/3.96=160.06
2)SCP/Total Weight: 352.2/580=60.7%// 160.06/263.64=60.7%

E.W/SA=1.93

++++++++++++++++++++++++++++++++++++++
NOTE: if the hull weight goes up 50lb(22.7kg) then the ratio changes to 56.8%
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This is no guarantee of anything-just very interesting numbers.
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Also check this out:
This is the intro to a paper by Alan Smith -who helped get the first two person bi-foil monofoiler in history flying:

Proposed Foil Bourn C Class Cat
Challenger 2007

This presentation puts forward an overview of a proposed new generation of C Class Catamarans. It claims that the fitment of an appropriate foil system will result in a SOFTSAIL(emphasis added) configuration being up to 70% faster than rigid wing non foil fitted competition. Some performance information is provided and comprehensive design files exist that justify the claim. It is in effect a wind powered "air" craft with its lifting and control surfaces in the water. The design process employs state of the art aerodynamic performance,stability and control methods.
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The presentation can be found here:
http://www.highspeedsailing.com/sailing.htm
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THESE FIGURES WILL BE REVISED AS MORE IS LEARNED
Thanks to Steve for the info................


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Design For Flight