Fastest Sailboat on the Planet!

Re the GPS
It doesnt matter so much the sampling rate what matters is were you getting differential updates while you did that to allow for the postion to jump ...how far and how often?
sailor doing 30m/second and the gps postion might be jumping 30m? so what speed do you get?

 

Another excellent post. You make some very valid points.

I see the trench like a full scale wind tunnel. The wind is high, but the running surface does not have waves consistent with wind speed. Somewhere between the absurdity of sailing in a wind tunnel and sailing in open water lies a venue that allows all comers to attempt sailing speed records on equal footing.

Where that happy place is hard to pin down (as you state so well).

I think I made the statement much earlier that sailing speed records depend more on conditions than on equipment. It would appear that smoother water favours shallow draft vessels to a very great extent.

Trying to use a distance from obstruction such that the sea state is fully developed for the wind speed would place a 500M course very far offshore indeed. I cannot lobby for that. No one would consider setting a record in the 32 foot waves that accompany 40 knot breeze.

I find your arguments convincing to the point that I question my original premise. If we allow any less than natural conditions of waves proportional to wind speed, it does not really matter much if the high wind, limited fetch smooth water is natural or man made.

I'll echo Boston's comment that this has been a very engaging discussion. Thank you. It leads me back to the opinion I held before I started to participate in the thread; 500M sailing speed is too abstract for me to take seriously. Speed average over less than 18 seconds has no meaning in any other context.

R

 

That is not how GPS speed is calculated. GPS speed comes from Doppler shift in the signal.

 

You would need to check if a gps unit actually used doppler or trackpoint calculation for speed.
I would guess if the manual didnt say it was doppler speed then it wont be?
anyway so if you have a bad HDOP how well can you measure the doppler changes?
with a unit that tracks how many satellites...
Is there no GPS spec for this organisation?
Let alone on shore monitoring?

 

B

I actually understand where you & others are coming from entirely. I just happen to work in a setting where we have lots of limits associated with technical considerations, but we have to deal with cases where people have used emotional arguments to make bad rules instead of getting down to real technical issues. As such, you can probably see that I have become somewhat stubborn when it comes to this kind of thing.

If I sail along the natural strip of land that encloses Cape Hatteras, with a wind that is blowing out to sea, it is just plain old normal sailing with no man made advantage. If I am in a bigger boat, I will need to be a little farther off shore. If I am in a smaller boat, I loose some of the advantage of size (bigger really is better in boats) but I can get a little closer where the water is a little smoother. If you pick any arbitrary limit on how close I get, I simply cry foul and say that you are making rules that favor the big guys with the deep pockets and the big boats.

Just saying that being up close makes it possible for some advantage to occur is not good enough. Big boats can also be up close if they can find a suitable location. Everyone has the challenge of finding the best location they can. Big boats just happen to have a huge advantage where relative chop (wave size divided by boat size) means that up real close does not matter as much.

With the speeds we are talking about, trying to push the runs offshore would just end up with anything not huge operating in chop that is a real problem. This sport is risky enough as it is (videos of the crashes abound), without moving the smaller boats farther off shore.

Go after stuff where shaping the wind is a question and there is both a better basis and a better chance of coming up with a good solution. We could simply suggest that a little coaching of the on-site WSSRC rep be done so that regular competitions stay as clean as possible.

 

GPS:

Shore based:

I would think that a relatively simple shore based DGPS system would provide the 100cm accuracy needed. The Trimble 1cm accuracy survey units are a bit of overkill.

 

These are good solid rebuttals to each of your points and it seems that although the kites should be allowed to compete that competition should be held on common ground or as the rules say "comparable conditions". Competitions held on artificial sites that favor a particular type of vessel should be disallowed in any all inclusive records category

 

Once again there is ample rebuttal to every question regarding the need for an additional review of these ditch venues and particularly there use of speed enhancing equipment and topography extraneous to the competing vehicles

I'd just like to see some of these guys who have worked so hard to build a real boat and see how fast it will go get some recognition rather than see them discouraged and eclipsed by demonstrably less capable craft that only achieve the speeds they do because of numerous and questionable interpretations of the rules well outside the mainstream usage of the terminology

The ruling body is going to have to address these interpretations eventually and so far it looks like they have just been trying to avoid the battle.

They originally disallowed kites for a reason and unless these venues quite pulling tricks like mechanically adjusting the water thus enhancing potential speeds and building wind berms offering additional enhancements in speed then there will be forever complaints from honest contenders wishing that the comparable conditions stipulation in rule 1 finally be enforced.

I'm kinda baffled at why the ruling body ignored the comparable conditions stipulation in the first place. Maybe I can develop some corespondence with them and find out what there thinking is.

cheers
B

 

Hi RHough
Looks like I need to ask the question of how are they recording their speed?
Clearly not with a Garmin Foretrex on their arm?
Cheers

 

This is one of the sticking points. The "approved" survey GPS units are too big to use on a board. The boards have to use shore based video timing.

When they get smaller GPS units approved the boards will be on even footing with bigger sailing craft with freedom of course during the run and the ability to pick the best 500M out of each run. As it stands now they either sail the course that is exactly parallel to the shore base transit (even if it is not the best angle) or they sail extra distance to get their time.

The Landsailing Speed Record of 126.2 MPH was documented and ratified using a sub $200 GPS Data Logger: Locosys GT-31

Here is a setup guide for boardsailing: GT-31 setup

These things are tiny:

Size 90H x 58W x 24.5D mm
Weight 97g

If these units were used by the boarders and the GPS data compared to the shore based video timing, it would be easy to see if the data was accurate enough to use for record attempts.

There is a small but significant difference in the rules and method for recods set for landsailing. Landsailing uses GPS recorded speed over 3 seconds. They measure the speed directly, they do not measure speed over a fixed distance. Thus Horizontal Position Error (hpe) is not as big of a concern.

The GT-31 data shows a .9 hdop (hpe) rather than the .1 required by current WSSRC rules. Hpe at the start and finish are added to the 500M positions. Worst case for a boarder using a GT-31 is a 500 + .9 + .9 = 501.8M run for a 500M record. At 30M/Sec (~58 knots) this is about .06 second potential error in timing over 500M. As I understand the system this could result in a 30 M/sec run being adjusted to 29.89 M/sec which is a .36 % error. This is about .2 knots at 58 knots.

GPS speed on these units is accurate to .1 MPH or .087 knot. Thus the direct GPS speed is more accurate than the calculated speed based on time/distance with hpe added.

 

RHough,

Good discussion of GPS details.

In addition to the gadget considerations is a more fundamental difference in objectives.

On water, the desire was to have the speed record based on using the wind only to achieve a speed. Given the potential for a sling shot effect from manipulation of a rig, manipulation of a kite, or even an intentionally curved course, peak speed was not seen as a good measure for the outright record. Requiring an average speed between 2 points 500 meters apart has probably done a good job of keeping the record as a clean demonstration of wind power only (at least for now).

On land, the contenders have all been rigid wheeled craft with a fixed wing (or possibly soft rig or wingmast rig) attached. I do not think there are much concerns about using any sling shot approaches on land. On land there are also real limitations for acceleration and coast down distance available. Given the above, they are OK with a more peak speed based record.

Boston,

You keep saying you want a couple hundred feet offshore to level the playing field. This would do nothing of the sort. It would be a clear advantage to bigger boats where the relative chop (wave height / boat length) is smaller.

You still have failed to explain why a big boat can not run close to a shore.

In order to pick any given distance off of land, you need a real basis for the value. Big boats can run a lot closer than 200’. They probably just do not need to. Hydroptere was well within the sight of land on their record run. They could have been closer to shore if they had wanted to. For them, either it just was not needed, or the trade off of less clean wind would have offset the advantage of smoother water.

I think most people that follow sailing records know what is what. If you want a “real boats in real settings” fastest boat, the following record is what I would point to:

Transatlantic W to E, Ambrose Light – Lizard Point, Aug 2009, Banque Populaire 5, Trimaran, 131 ft LOA, Pascal Bidegorry, FRA, 3d 15h 25m 48s,
32.94 kts.

As soon as you put together your challenge to the 100+ ft French Maxis that dominate the open water records, I will cheer you all of the way. I would even offer help you in my spare time if you wanted it. Just let me know when we start.

I do not think anyone is going to confuse the rocket powered Thrust SST with an F1, Nascar, Baha 500 car or Top fuel dragster.

 

After re-reading the above, I do not like my “real boats in real settings” statement. Hyroptere is still tops with those words. The BP5 record fits more of a "fastest boat in any real passage setting" description. I was hopeing that the big foiler would have made a run for the transatlantic by now, but they seemed more focused on the around the world record.

 

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Hydroptere would need at least 8-10' of water in case it came off the foils so they would not hit bottom.

 

I agree totally that depth would be needed. That just means it has to be a location where the bottom drops off fast. Water 10' deep at less than 200' ft offshore does not sound hard to find. Most non-foiling big speedsailing boats would also need a similar depth to allow good aspect ratios on the dagger board.

Actually there is much much less need to run close for Hydroptere. Their choice of foils seems to handle chop fine. I think it was really the gusty conditions that led to their one crash, but it is kind of hard to say given the limited info they shared after it happened.

 

I agree. A 3 second average is too small until we see 300+ knot speeds over 500M

What we have now is technically not a speed contest, but a race over a 500M course. The results are expressed as speed but for most distance events the results are expressed in time. The headlines should read. "Sailor breaks 19.43 second (50 knot) barrier." or "US Sailor sets new record for 500M dash at 17.45 seconds." World records over distance in other sports are expressed in time, not speed. 100M dash - 9.58 sec, Mile - 3:43.13 etc.

Who cares if the course is curved or straight? It is speed that matters.

The accuracy of WSSRC records are based on .01 second resolution. Valid increments vary by the type of measurement system. GPS data has to be interpolated as it stands now.

My point is that current $200 GPS systems are probably accurate enough to ratify new records using the current method. They would certainly be accurate enough if a local DGPS beacon was set up. I have to think that setting up a local DGPS beacon would be no more expensive than setting up the video timing system currently in use.

It would put the boards on par with the bigger boats and give them the freedom to sail their best course.

R