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 [...]

Ready for the "Rocket"?

24 April 2011
It’s great to see Sailrocket back at Walvis Bay and read Paul’s blog describing the action. I can’t help but comment on the fun he had in the first tow test. These craft do not tow well, because you can’t tow from the correct point or in the correct direction. Yep I’ve had my fun with this but I rarely tow anymore unless the wind drops, or I break something.

To properly tow these craft would require a chopper, pulling in the same direction as the resultant from the wing, while the chopper is advancing forward parallel to the craft’s path at the exact speed of the craft. Note that the chopper cannot change altitude, it just has to maintain a constant upward and outward tug while holding altitude and advancing forward. The main hydrofoil would counter this ‘tug’ and advance forward normally. (You’d better have a really good chopper pilot or you’ll trash the boat.) The action will be similar to a water-skier skiing off to one side of the tow boat and holding that position, rather than following directly behind the boat.

Any sailboat on a tack is essentially “climbing” the true wind in a manner that I’ve described in earlier posts. I’m still objecting to any suggestion that a sailboat uses the apparent wind to generate more speed, including going faster than the wind. Slower craft are doing the same thing as faster craft, it’s just that they are too inefficient to exceed true wind speed. I’ve been thinking I might get into this a bit more because I think a good understanding of what is really driving the boat will help us figure out how to go faster.

Never fear, I’m sure that many sailors and aerodynamicists think I’m a total kook for my view on this, but we’ll see who has the last laugh (I often do!) :-)

Bob
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