High-Speed Sailing

Vessel Name: Sailien
Vessel Make/Model: Experimental/custom
Recent Blog Posts
28 September 2013

The America’s Cup

I watched, with interest, the videos of the 34th America’s Cup. At last we have fast sailboats engaged in a competition that is fun to watch. The virtual images (such as course boundaries, distance grid lines, separation between boats, etc.) overlaid on the real images really helps to keep the race [...]

31 August 2013

100 Knots for Hydroptere?

The latest news from Hydroptere is that they have plans for a 100 knot sailboat. This was posted on 26 Aug 2013, so look for that date at this address. http://hydroptere.com/en/the-news/last-news/

17 November 2012

Aptly named Sailrocket, blasts off!

While yet to be ratified, Sailrocket posted an average speed over 500 meters of 59 knots. I will not be surprised if they increase their record into the 60 knot range during this record attempt.

02 January 2012

More drag for VSR2?

I want to start by pointing out that the whole VSR2 team has done a stellar job and has demonstrated conclusively that the forces that drive a sailboat can be aligned for roll stability without using ballast and without using any down-force. (Trifoiler achieved roll stability by using down-force, but [...]

18 December 2011

My analysis of Sailrocket

I copied a diagram of VSR2 (wing doesn’t show well) and added in the major force arrows that apply. Be aware that these arrows are not correct in terms of scale (length) and some of their locations are guesses, however I believe I’m correct enough for us to learn something about what VSR2 has been [...]

23 October 2011

60 is within reach, what’s next?

I have been watching Sailrocket’s progress with great interest and there’s no question they have a winner. I fully expect to see them reach 60kt in the near future. Sailrocket has now demonstrated what I first learned with my models and again with my full-sized prototypes, that if you get the forces [...]

60 is within reach, what’s next?

23 October 2011
I have been watching Sailrocket’s progress with great interest and there’s no question they have a winner. I fully expect to see them reach 60kt in the near future. Sailrocket has now demonstrated what I first learned with my models and again with my full-sized prototypes, that if you get the forces that act on a sailboat in proper alignment, the only limit to your speed is efficiency (for the techies, that’s L/D) and, of course, the conditions you’re sailing in (wind strength, sea state, etc.).

There have been some interesting comments on Paul’s blog including one asking what you call the craft when it’s only contacting the surface at two points (fore plane and aft foil). Paul’s reply was tops -- that’s it’s an aero-hydrofoil in acknowledgement to Bernard Smith. I titled my patent the same way, to show where my own craft derived from.

I’d like to expand on craft stability with reference to the number of points of contact to the surface. If we look at a child’s wagon we note four wheels that support it stably, whether it’s moving or not. Compare the wagon to a catamaran with the two bows and two sterns being the main points of stability, like the wagon wheels. A tricycle is a bit less stable than a wagon, but still quite stable while at rest or in motion. Compare the trike to a proa in which the bow and stern of the proa form two points and the ama, the third. A bicycle, with two points of contact is totally unstable unless in motion and even then balance has to be maintained by active control, however, if we put “trainer wheels” on the bike, it will be stable at rest or in motion as once again we have four points of contact. A mono-hull and a trimaran could both be compared to a bike with trainer wheels (although I risk the ire of mono or tri sailors for this – no belittlement intended). The monohull uses a weighted keel to add stability to a relatively narrow beam, while the tri spaces the amas fairly widely. There is one more possibility to consider, a unicycle (!) as we know this is unstable under all conditions and it takes great balance and skill to ride one successfully. There are a few sail-craft designs aimed at one point of contact. We can’t go below one point of contact, because as soon as we disconnect from the water, we loose all power (check my earlier posts explaining how a sailboat works using the “squeeze” between the wind and the water).

Here are two sites of craft aimed at one point of contact with the water; I believe there are others but I know of none that are active at this time.
http://www.dcss.org/speedsl/sheerspeed.html http://www.monofoil.com/boat/index.php

There is really no reason one point of contact can’t be quite successful, however, it will take constant, active control (whether manual or automatic) to maintain stability.

Bob
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