New low-cost "hardware store" racing class; input on proposed rules

Well put, unless he really meant a wing mast rather than a rotating one, but even then not anything to fit and forget

I doubt if many people will build a RS300 copy, it was a bit too extreme for most people (and yes I have sailed one). I assume you mean the Duflos Moth? That is very similar to the Mistral which is hard to sail, as I mentioned earlier

The Laser actually has a big rig for most people, hence the popularity of the Radial, so it could work well on a broad range of hulls form long narrow ones with wings to heavy home build experimentals. I even have a Laser rig version of my Strike 15 trimaran

RW

 

Just a quick questions to the ex-moth sailors on here: Was moth racing much cheaper (relatively) back in the day? Or alternatively, could an inexpensive but good design become world champion? Now that seems pretty much impossible.

 

I wrote about it earlier, maybe on the yard boat thread. My first Moth cost me GBP100 to build, ply, polyester resin (no epoxy back then) Needlespar spars, dacron sail (wood battens)

I was earning GBP13 a week. So it took me 8 weeks to earn the materials to build my Moth.

How does that relate to your income now, relative to buying/building a Moth?

Most people could build a competitive Moth quite easily until about 1980, after that they got too complex for most people except pros and semi pros

Richard Woods

 

I find this discussion fascinating. If I understand correctly, you are trying to get a wingsail to work like a mast and sail. Admittedly we are probably biased, but we would make a symmetric wing, and control its camber, possibly twist, and AOA, (angle of attack). This indeed would have relatively simple (in comparison) controls.

Please do not choose a standard sail or rig for all to use. To us it would lose much of the appeal of the new proposed class.

 

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I was referring to wing masts, not wing sails/rigid wings. Like many people I have years of experience with wing masts, but none in wing sails.

It would be interesting to see simple sail controls in a wing sail - Steve Clark and others certainly give the impression that making a reliable adjustable wing sail is a very challenging task.

Maybe there needs to be two options for rigs - one home made and a stock Laser rig - since there are good arguments for each one.

I'd be surprised to see a solid wing sail catch on with all the owners in the context of this boat, which seems to have cruising aspirations; even transporting them and stepping them would seem to be something of an issue. One class we used to own had a fairly large wing mast and it created significant issues with mast stepping in some conditions, as well as with handling the boats ashore.

I'm open minded with solid wings and obviously in multis they have had enormous success, but given the lack of success with them in monos, may I ask whether they have the correct lift/drag characteristics? I'm certainly no aerodynamicist, (hell, I can't even spell it) but I do know sailing history and there seems to be something very significant in the fact that many attempts at wing masts in monos have failed, demonstrating that the claimed advantages may be outweighed by other issues.

I thought (from info presented here by Mark Drela and Tom Speer and other sources) that a thin foil actually had many advantages - couldn't it just be that the characteristics of a mono suit a thin foil (soft sail) and those of a fast multi suit a wing?

 

I'm with CT249 on this one. But there are lots of papers on wing sails, probably nothing you don't know on the theory but practicalities may be challenging, especially if you are buying everything from Home Depot, and thus staying in the concept of the class....

http://cfd.mace.manchester.ac.uk/twiki/pub/CfdTm/ResPub261/thesis.pdf

Tony Marchaj told me the best rig was the wing sail, the second best a "slat" jib and squaretop mainsail, as seen on Merlin Rockets, for example, since the 1950's

Richard Woods

 

Richard, thanks for the note from Nils. Perhaps i should refer to the lecture series i gave on composite aero structures at Manchester and Bristol.

As i said, wing sails are on our ‘list’. As ‘lift’ is generated, at least at low angles of attack (windward work on sailboats), by the different pressures generated either side of an airfoil, aviation basically abandoned single sided foils in about 1912. Thereafter all lifting foils, except for a foray into early hang gliders, have been double surface. Controlling the local ‘lift’ for control purposes has also relied on separate surfaces (Ailerons, flaps, slats, spoilers) since 1914 when “Wing Warping” the direct equivalent of a sailboats draft control, twist control, etc was abandoned.

As soon as the wind is ‘free’ i.e. reaching or better, the advantages of the double sided foil become disadvantages unless speed can move the apparent wind back forward again. I suspect Ice boats and Multi-hulls are the only boats slippery enough to take advantage of this..

“soft’ sails have many historic advantages, not least they can be ‘reefed’, ‘furled’, or otherwise stowed for convenience on the boat, transport, and stowage.

I suspect it is the versatility in handling different wind directions that finally overwhelm ‘solid’ sails in favor of ‘soft’ sails.

For us a starting point might be the many variations of a ‘junk’ rig with ‘ribs’ surrounding the mast, and able to be collapsed vertically for launching etc. There are many of these having been tried in the past, but few where minimal cost was the goal. Its not so long ago that airplane wing skins were sewn onto the ribs, there are specifications for the number of stitches per inch, certainly cheap enough. A combination of Irrigation pipe, builders foam, pultruded carbon rods, and Mylar or (powerboat winterizing) shrink wrap seems to be a starting point. For aerodynamics, think in terms of aft loaded symmetric foils, see below.

http://airfoiltools.com/search/index?m[maxCamber]=0&m[sort]=5

We don't want too complicated so as to scare off the new entrants, but you guys wanted to ‘race’ and we are old enough that we have to rely on cunning, not athletics.

 

Dinghies with asymmetrics don't sail with the apparent wind aft of the beam unless it is very light winds. But conventional singlehanders are too slow to do that. So many boats sail fastest by the lee with lots of sailtwist (eg Lasers) which is what makes the unstayed mast so attractive. Also you can sail down more waves if you can go either way downwind without gybing

I suggest checking the AYRS magazines, most are now free online.

I assume riveting or spot welding wing panels is structurally the same as stitching?

You will need to keep weight down, so your complete above deck level rig, of say 100sqft, should weigh under 20lbs

One advantage to a wing sail might be that it is buoyant after a capsize so you won't turtle. And it will have to be strong enough to survive a capsize at speed. I accept making it strong enough so it doesn't tear if the crew fall through it is asking too much

RW

 

Wing Rigs

Adam May made a wing sail for the Moth that was strong enough to walk on:
click-

 

Alan, I am thrilled wing mast and wings are getting consideration. The percentage of cord will have a lot to do with construction weight and handling. To be light enough means that it will get fragile as it gets larger. What I like about wings is all the volume available for internal structure. The sail portion just needs to be enough to reef.

Have you been around these forums enough to see the relevant designs and theory? Gary Baigents 'Cox's Bay Skimmer'? Tom Spears page?

MSDS for tarp? I have never seen one and I would not trust it anyway based on past experience with cheap Chinese materials with hazardous substances.

On the other hand mylar for drawings would be great stuff in my opinion. I have a few rolls I am hoarding since my company threw them out. PBT if I recall... top notch UV sabilized... I don't know what the dimpling is but I know it comes off with a stiff eraser. If you are testing used and want to compare I have NOS -I think from about the late 80s when we ended manual drawing.

It seems I am still catching up to your sense of humor. "Psychological warfare"? I sure hope that is a joke because the targets are your first responders when you are bobbing about in bits of crumpled boat.

Richard, I don't know if your going around in circles comment was about something I said but my post was nearest in proximity. Do you want me to NOT ask your opinion about developments? I don't see any reason some historical design could not be used and as far as why develop for this class -because its fun. The same justification anyone has for a pastime.

CT -It appears to me you are arguing about wing masts in one design and much higher end development classes. In the context of short rigs for less than ~$300 I just don't see that they apply. Simply stated this class is a great opportunity for a wing mast rig THAT DOES NOT DEPEND ON MAST BEND FOR SAIL SHAPE. Even if you did want bend -why not just bend the track? The large wing mast would need no diamond rigging or spreaders. 2D analysis indicates adequate control and coefficients available from mast rotation which could be relative to the boom, like solid wings. Twist control could be from an above the boom solid vang. Alpha, Camber, and twist -That's it! I have great respect for Steve Clark, but are you comparing Little AC cats to $600 dingys? Those are opposite ends of the spectrum. All I can offer is a saying credited to Confucius -Those who say it can not be done should not delay those who say they will try.

It sounds like there are enough votes for allowing used rigs to start the first fleet. I am not sure about duration and control but I think it needs to be limited to rigs that can be duplicated new for less than the entire budget (for example). I even like the idea of inviting some one design boats to some events -relative performance would be interesting. I had to laugh when I read that it should be some top rank sailor -why? And why would they want to participate? To the original spirit of the rule a comparison would be with both sailors of similar experience in their boats AND novices that only get an hour of instruction in the boat.

 

No Skyak, I wasn't refering to you at all. But this is a long thread and has been going for years, so it has being going in circles, hopefully a slow spiral would be a better description

But it is getting away from the original Petros concept. I would still like to know which hardware store I can visit and come out with the materials to buy a wing sail that looks like the one Doug posted, even though the sailor is standing on the structural part, not the sail part. We all know that C class cats have torn/broken wings during capsizes.

I suggested Lady Helmsman as the curved trailing edge gave automatic twist control, or so I understood it. And it was built in wood and definitely didn't bend

I guess anyone who buys a used Hobie or Laser can enter, providing it costs under USD600? There was a unused Windmill on a PNW CL for USD600 last year, don't know if it sold. A quick look showed a couple of Hobie 16s with asking prices of 700-800, so no doubt 600 is possible. Or is that against the spirit of the class - I would have thought so.

RW

 

OK, this is where I must be missing something (which is highly likely ) , because it seems to me that people like Mark Drela and Tom Speer are claiming that thin foils are often more efficient;

If Mark Drela doesn't mind me quoting from a post of his here; "Thin airfoils are capable of the highest CL and CL/CD values, but only within a narrow CL range (or alpha range).... a soft sail allows the possibility of changing the camber of a thin airfoil, which can greatly extend the low-drag range if done appropriately. So a thin airfoil which always has the appropriate camber shape dialed in at any given operating point will in general be superior to a thick airfoil."

And if I can use a Tom Speer quote, again from here;

"the notion that because aircraft wings are very efficient and have thick sections, while sails have thin sections and generally lower lift/drag ratios, and therefore a thick sectioned sail will aerodynamically superior to a sail rig with a thin section simply because it is thick, is a mistaken idea. Airplanes have thick sections because they are structurally stronger and because they have to operate efficiently at low lift coefficients in cruise. This is generally not the case for most sailing craft, except for very high-speed craft like landyachts and iceboats.

A sail rig can operate at comparatively high lift coefficients even in high winds because it has the luxury of being able to reduce area. This makes the narrower operating range of the thin section acceptable."

Please forgive my confusion, because to me it seems that we have experts here who are at odds with each other.

 

I didn't say top-ranked sailors should be invited to sail these boats (as it turns out it looks like it will happen anyway) but merely that if these boats raced against top-ranked Laser sailors then we would get a useful means of compare the performance of boats in different areas.

The performance of Laser sailors in the top 30 of most significant sailing countries is probably pretty even. Therefore their performance can be used as a yardstick to measure this class against.

For example, if Richard builds a boat and races it in three regattas against a good Laser sailor and finishes 5% ahead on average, and I built a boat and raced it in two regattas against a good Laser sailor and finished an hour behind each time, we would have a pretty good idea that his design/sailing/construction combination works better than mine.

The same sort of thing has been going on informally in design forever, but with the net we could get more information more easily and perhaps build an interesting performance ranking, as the Kiwis do with Racetrack.Org.

Another way to rank the performance of boats in different areas is to use GPS, but that can be heavily distorted in many ways (for example, those who live in areas where strong winds and surfing conditions are common may get much higher speeds) and can also encourage boats that are not good all-round performers.

 

As is often/usually the case I agree with your comments. And the differences in opinion is in part because, as I said elsewhere, the USA has never had the "build your own racing dinghy" that we have in the UK and (it appears) Australia/NZ

Having said that, if I sailed against the 30th ranked Laser sailor in the US and then the 30th ranked in the UK I know which one I'd probably beat! But I agree with the principle

But your comments have inspired me to start a new thread (wait a bit while I write the first post)

Richard Woods

 

I bet a doughnut that:

A) There will be no agreement before noon on January 1st, 2020,
B) There certainly will be no club before that time,
C) There will be, therefore, no boats built before that time, and

D) There will never be a race.

This thread is not a discussion about a new club, class or race. This thread is just another meaningless, endless thread on a meaningless board on the internet, and takes it's place next to the conspiracy threads, the blood-drenched survivalist fantasies and the little green men from mars.

It is not here to promote a race. It is here so all the participants can attempt to show how bright they are.