Hey will, thats what i said, heel the boat away from you- to leward, it heads up, to windward (on top of you) it bears away. Ive done the rudderless sailing thing in a lasers and toppers…
Luff 'em & leave 'em.
Sorry Matthew, I read your post incorrectly… Mea Culpa!
Isn’t rudderless sailing fun!
- Will
Will Gorgen
Still thinking—
IF, there are two CK boats available to sail together on the same water.
One of the boats is able to make full use of the CK system, the other boats CK system should be Turned OFF with its keel fixed in the standard position, inline with the Mast.
Tune up both boats to suit the prevailing conditions,and have a few races.
There will be a winner, ok, change Skippers, have some more races, another winner.
Same Skipper wins all the time?, get someone else to sail the slowest boat!.
Race again, then change Skippers again, this time the best boat should start to show.
Change the boats, the one with a locked keel, now goes active, the other one should be locked.
IFthe Active keel boat continues to win, with either Skipper it is fastest and the CK system is worth doing.
Any offers ???.
JayDee.
John, it migh be possible to predict the outcome of the race you suggest ahead of time but it would still be fun to try.
If you compared two identical canting keel boats except that on one you centered the keel the boat with the centered keel would have significantly less available righting moment than the boat with the canting keel. It would be beaten in conditions that required the keel to cant.For instance, the boat with the active keel ,in a wind that required it, might have to cant its keel ,say 30 degrees. It would sail nearly flat(mast vertical) while the boat with the keel shut off woul be heeled about 30 degrees to develop the same RM since they both have the same sail area in your example.
In light air or dead downwind where the canting keel wouldn’t be used(except maybe to heel the boat) the boats would be exactly even…
Doug Lord
–High Technology Sailing/Racing
Doug,
There must be two CK boats somewhere in the World to try this system out.
Or are all the CK boats in splendid isolation, unaware of the others?.
Have you never had two CK boats at your disposal?, if yes, I am amazed you didn’t try my idea.
The bulb weight of a CK boat is less than an identical but non CK, why? if the weight was exactly the same, there would be no need to cant out to 55 degrees.
Two Hulls from the same mould, one made into a CK and the other standard, will always perform differently, one is a lot heavier and lower in the water, it may have a longer water line than it sister boat, but not enough to matter.
Is this the “Stumbling Block” that is preventing direct comparisons with Non CK boats?.
On the Forum I read of folk wanting to race against a CK boat, but not able to, because the Hull lengths are different, but there is another, major difference, CK boats are SO light, Bulb wise, the CK system is required to enable them to sail!.
John.
Still thinking - - - - -
John, about 9 years ago a friend and I put together two identical 70" canting keel boats. We raced almost every weekend for a year. The boats were not a very good design but gave us a lot of experience using a canting keel.It never occurred to me to try the experiment you mentioned before because our experience was that if both boats were sailing together and hit by a gust the guy that reacted first with the keel gained alot. If two dinghies are hit by a gust and one crew reacts quicker to keep the boat flat they can make a big gain.By moving the canting keel outboard you generate more power in exactly the same way you do hiking out:if you don’t hike and he does he gains…
This is a fact of racing this kind of boat in conditions where you need to move the keel.
The Ultimate Warrior produced in New Zealand would have the most numbers as they are the only production canting keel model as yet.
The physics of a canting keel model are identical to the physics of a canting keel on a big boat-and canting keels have proved time and again to be faster than other boats their same length.The hydrodynamics of the appication of canting keels to models are different than full size affecting the foils in area and t/c ratio.
I’m sure as canting keel boats become more numerous in rc sailing that they will prove to be as comparatively fast as their fullsize sisters.
About canting keel boat design: if you took a fixed keel boat 1 meter long and you wanted to design a boat using a canting keel to compete against it the physics of a canting keel design:
1 ) allows you to reduce ballast around 40% while having substantially(up to two plus times) increased righting moment for a given angle of heel. The canting keel boat can develop the righting moment at ZERO degrees of heel that a fixed keel boat develops at 30 to 40 degrees of heel. This adds up to pure speed since the sails of the fixed keel boat are much less efficient than are those of the canting keel boat in that situation.
2) requires you to have extra lateral resistance when the canting keel cants beyond about 25 degrees from vertical. But because of the fact that you have reduced the displacement and hull wetted surface and because the canting keel boat is sailing vertically or at a small angle of heel the foils used for lateral resistance are more efficient and can therefore be reduced in area. They can also be reduced in area because of the greater speed of the canting keel boat.
The drag of the exta lateral resistance is outweighed by the tremendous extra power developed by a canting keel.Some forms of the extra lateral resistance required by a canting keel boat are/can be retractable.(daggerbard,gybing daggerboard, twin asymetrical daggerboards, centerboard)
3)- allows you to use CBTF: besides the “normal” advantages of a canting keel mentioned above CBTF allows twin foils to be used to develop ALL the lateral resistance relieving the keel fin of that duty 100%. This is done by turning both foils a small amount to weather(called “collective steering”) and reduces drag on the hull since it is no longer crabbing sideways like a fixed keel boat(and some canting keel boats) and reduces drag on the fin because it is no longer developing induced drag as a by product of lift since it is now moving straight thru the water. One of the things that will be interesting to learn in model racing is weather or not a CBTF boat is so much better to weather than another canting keel boat that it stays ahead if the other boat uses some sort of retractable foil downwind or in light air.
In summary, the design attributes and requirements of a canting keel system must be understood by the designer in order to take full advantage of the speed potential.
Hope this helps…
Doug Lord
–High Technology Sailing/Racing
From what I have found from sailing my boat the boats are very hard to sail with the keel in the centre and with heel on as the centres of resistance are changing the boats are designed are around the keel provide no resistance and the balance of the boat is figured out using the fore and aft rudders as the lateral resistance. As soon as yuou ask the keel to be centred and the boat heels over you loose alot in ground and fall off to leeward quite quickly as you do not have the projected surface area of the rudders working here for lateral resistnace and the keel does not contribute here as it is so small in cord length and it is also heeled with the rudders you have very little exposed surface area and the boat becomes very hard to sail as you have little steerage this may change with deeper rudders which I am working on for my second boat but I think that my original rudders are pretty goods as they are with more depth I think it is going to turn into more drag for teh light airs and this is where these boats suffer.
But as soon as you cant the keel out the two rudders come into play and the boats are totaly different to sail than a fixed keel boat and certainly test your use of controls. the boats are very quick to turn and they carry alot of speed out of the tack and I am working on a new keel mechanism to help with this as at the moment I ned to ease the boat through the tack as the winch cannot get the keel canted before the tack is completed and the boats tend to power up straigh out of the tack which I believe now requires a faster system than I have at present. The original system was done to make sure it worked though with out spending to much money on winches and so forth.
Well best get a cold beer as it sure is hot down here at the moment.
Cheers Blair