Just spotted an interesting post by Martin Van Meurs on gps-kitesurfing: www.gps-kitesurfing.com/default.aspx?mnu=forum&forum=1&val=9321

To sum up, it appears that shallow water may actually result in INCREASED drag, NOT a decrease in it...

And that's just the beginning of what MVM's got to say....

.... check it out....

Seems like he's got it all wrong.
The difference is between planing and nonplaning.
One definition I've seen of planing is thus.
" planing is when the hull speed exceeds bow wave speed and climbs over it"
(That's why it takes more effort to get on the plane, than it does to stay there)

It's the same effect, in both cases. The ground effect increases the size of the bow wave. (water can't flow down around the hull as well). So at subplaning speeds the hull is trying to climb up a steeper bow wave. but at planing speeds the hull has overtaken the bow wave and is surfing down a bigger wave, so speed increases.

So you'd expect it to be harder to get on the plane in shallow water, but once there you go faster.

I agree with Decrepit.

Get Martin to explain how a skimboard works then.

He is wrong on every level.

WSSRC IS an independant umpire.

The independence of WSSRC decisions is definitely open to question. The board of the WSSRC is as subject to political bias as anyone else. Only someone completely disinterested could be truly independent.

The pilots are quite right that shallow water increases drag, But this mainly applies to displacement hulls.

For planing hulls I believe that there is a reduction in drag in very shallow water. Using a skim board (or skiffleboard) on a film of shallow water on a beach illustrates this clearly although there is an opinion that the effect decreases with increased speed. That effect may not be significant at 50 knots.

The fundamental question about water depth is whether this matters at all. I would argue that it is just another advantage that one gains from the natural environment, just like flatter water in a canal or stronger wind in a Gale. It should be considered sailing if the sideways resistance for propulsion, (countering the winds force), comes from contact only with water, not the ground or ice.

As far as kitesurfing and windsurfing goes the depth of water is self limiting. It does not matter at all for windsurfing and kitesurfing class records.

Am I missing something here, what's this fight all about? Is this just Martin Van Meurs slugging it out with the WSSRC/ISAF/ISWC for personal reasons or is there something important at stake here.

If it's about sailing speed records what's the problem, you want an officially recognized one....go do the WSSRC events or attempts following their rules, be the fastest and you can claim to be the world's fastest sailor and the "outright 500m or 1 nautical mile world sailing speed record".

If you want a gps 10 second record go do it and lay claim to the "fastest gps 10 second sailor in the world using 2 handheld GT-31 GPS units with xxxx firmware analysed by GPS xxxx software", there's no one stopping you the last I looked.

So I repeat my question "what's this fight all about"?

I think you are missing something here Roo. There has been a discussion going on with the IKA, ISWA, GPS Speed Record Committee and WSSRC about whether they will recognize each others 'Records', about how the WSSRC could sanction class records that can be made more relevant and inclusive of Windsurfers and Kitesurfers and about whether the IKA and ISWA actually represents the interests of the great majority of Windsurfers and Kitesurfers.

However, I completely agree with you about the choice. Nothing to stop anyone following the WSSRC record chase if they so desire and nothing to stop GPS-SS and GPS-KS setting up a GPS-Speed Record Committee to 'officially' sanction their own GPS Kitesurfing/Windsurfing World and National 10 second records (Or any other time/class for that matter).

It was considered preferable however, to try to find a way to have the WSSRC include our proposed classes and rules in their system. It seems that the WSSRC does not want to do that or even have serious talks about moving towards accommodating the obvious needs, so there will have to be a separate committee for GPS Speed Windsurfing/Kitesurfing Records.

I guess there would be nothing to stop you from setting up a committee to sanction a "North American 100m speed record" either, if you believed it would have any credibility.........

I didn't know there was such a thing as a "GPS Speed Record Committee ". I googled it and found nothing! Still doesn't answer what Martin is fighting about, the WSSRC has their records which already included class records for windsurfing and kiting, as well as overall and national. If you want to claim one of those records you play by their rules which are available for all to see.

If you want to have your own records then go ahead and do it rather than try to have someone else accept them, like the WSSRC, I don't see why they have to change when handheld GPSs are the new kid on the block.

At the end of the day any record will be judged by its validity and adherence to carefully thought out and implemented rules that are tested and certified by an impartial body that can provide proof of speed and valid testing certificates for the equipment used. At the moment the Trimble GPS system is the only GPS system that can meet those criteria and therefore is accepted for any type of official sailing speed record.

I look forward to hearing about fully tested and certified handheld GPS units that can be used for personal record attempts and will be recognised for their unquestionable level of accuracy and proof of speed.

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sailquik said...

The board of the WSSRC is as subject to political bias as anyone else. Only someone completely disinterested could be truly independent.

Surely Andrew it is more indepenent than windsurfers and kiters recording records for windsurfers and kiters.

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Roo said...

I didn't know there was such a thing as a "GPS Speed Record Committee ". I googled it and found nothing!

Ahhh, I guess of it does not turn up on Google, then it doesn't exist.........

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Roo said...
If you want to have your own records then go ahead and do it rather than try to have someone else accept them, like the WSSRC, I don't see why they have to change when handheld GPSs are the new kid on the block.

Well of course, Video timing was the 'new kid on the block' in the early '90's.......
And then Trimble GPS was the 'new kid on the block' in the late '90's.......
etc.

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Roo said...
At the end of the day any record will be judged by its validity and adherence to carefully thought out and implemented rules that are tested and certified by an impartial body that can provide proof of speed and valid testing certificates for the equipment used. At the moment the Trimble GPS system is the only GPS system that can meet those criteria and therefore is accepted for any type of official sailing speed record.

Can you point to this so called 'valid testing certificate' 'tested and certified by an impartial body that can provide proof of speed' for the Trimble GPS please? As far as I can see it does not exist. I would be very pleased to see such a thing in the public domain.

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Roo said...
I look forward to hearing about fully tested and certified handheld GPS units that can be used for personal record attempts and will be recognised for their unquestionable level of accuracy and proof of speed.

All accuracy is 'questionable', not the least of which is Video Timing and Trimble GPS. All any device can do is work within a certain level of probability or margin of error. Trimble has this as well, but ahh, I can't seen to find out exactly what it is at the moment....in the mode it is used for speed sailing anyhow.

I am glad to be able to report that the Locosys GT-31 with the latest firmware is what you are looking for. Now you have heard about it. Accuracy tested and certified to less than 0.05 knots for 20 second speed runs at more than 99.9% confidence, conservatively.

What is the speed accuracy for video timing and for Trimble GPS timing over 500m?

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yoyo said...

sailquik said...

The board of the WSSRC is as subject to political bias as anyone else. Only someone completely disinterested could be truly independent.

Surely Andrew it is more indepenent than windsurfers and kiters recording records for windsurfers and kiters.

Why would you assume that David? WSSRC is a body make up of Yachties to sanction records for Yachties. I guess they would be completely ambivalent about Kitesurfers/windsurfers threatening to 'take away' their Yachting records......... Yeah, right .........
The WSSRC don't seem to be the slightest bit interested in reducing the enormous costs of a WSSRC sanctioned record attempt or events to make them more accessible to windsurfers and kite surfers, or even Yachties that are not so well heeled. That of course 'protects' existing WSSRC records in a way that actually decreases their credibility. I remember when Chris Torckler demolished the then existing Nautical Mile world record. His GPS was not 'certified' and may well have been marginally less accurate than the timing devices used for the 'official' record, but the amount by which he smashed the record left no doubt that the existing 'official' NM record was a bit of a joke.
There are some very fast sailors and craft out there that can not afford the exorbitant cost of WSSRC sanction. This in itself makes the WSSRC records less credible.

Andrew, I think your fear of bias is based on perception (within the windsurfing community) rather than reality.

The WSSRC observers spend more time at wind/kitesurfing events than yaching events. Having talked extentively with Michael Ellison at St Marie del la Mer he showed no bias. Even 12 years ago he told me he believed kiters would eventually the record.

Now the ISAF may be a different animal and they did lean on the WSSRC but eventually the WSSRC convinced the guys in blue blazers to relent and allow kiters to have the record.

David, I have not doubt that the observers at WSSRC events have the highest ethical standards.
I was referring to the board of the WSSRC and those like the ISAF that pressure them. I am also sure that those WSSRC board members have high principles but that does not make them immune to bias. It is interesting that a member of the board would make a statement that they get more revenue from one big syndicate private record attempt than all the windsurfing/kitesurfing events together. That may be true but why would he even mention this?

Why would you assume that a committee of technical experts set up by, say, GPS-SS/GPS-KS would be any more biased or less credible than the commissioners of the WSSRC?

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sailquik said...
[br It is interesting that a member of the board would make a statement that they get more revenue from one big syndicate private record attempt than all the windsurfing/kitesurfing events together. That may be true but why would he even mention this?

Why would you assume that a board of technical experts set up by, say, GPS-SS/GPS-KS would be any more biased or less credible than the board of the WSSRC?

I think that was when Markus Schwendtner from ISA was getting stroppy with them and threatening to start their own records body and no doubt also threatening to withdraw the kite and windsurf attempts (and the fees they generate) from the WSSRC.

The WSSRC probably reminded him that it was no skin off their nose as the MI guys probably keep them in clover.

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yoyo said...

He is wrong on every level.

WSSRC IS an independant umpire.

having read the post on gpsss

+1

Hi guys,

As far as my informaotion goes the ground effect mainly relates to Air and ground and air and water. I contacted a pilot of the Rotterdam harbour and he told me things are way more complex than just linking ground effect as occuring in the air and link them to planing hulls and say: here is your proof.

Skimboarding is something else as well, since water is only used as lubricant. Obviously a kite could potentially be used as a skimboard, so a definition of sailing is extremely important in order to be able to come up with proper rules and something our GP3S tech cimmittee has pleaded for for months in a row.

The WSSRC says it bases itself on a scientific report presented to them by the Wolfson Unit of the university of Southampton. Do you feel it's fair for us to ask for that given report so we can cross check the facts presented in that given report?

Whom can we express our concerns too?

Remember, there are no kite and windsurf representatives within the WSSRC board!

We tried to ask questions to are formal IKA/ISWC representatives for months in a row but they didn't repond to a single question and stuck their feet in the sand by referring to the GPS handheld case alone and neglect all other standing questions.

Simple question:

Has anyone ever laid his/her hands on the so called Wolfson Unit Report and their findings on shallow water to see how this relates to the rule as it's now presented in the official WSSRC rule book?

On top of this another thought:

It seems as if some of you are saying the WSSRC is an unquestionable institution which stands above the law. Even the laws of physics. Just scroll through their rules and see what they are claiming, then have a realistic look on the true limitations we have to check accuracy levels of standing record claims (current, interpolation ect). If you would perfom proper scientific tests records could only be based on full knots, not even tenths of a knot, let alone hundreds of a knot, like done right now.

It doesn't really matter if we all agree the hunt is set up in a way which is fair to all and we all know margins can be disputed, but it does matter if given crafts are highly favoured over other crafts and there is no one left to fight for the rights of small craft.

I can;t stand injustice and I will do all I can to keep on fighting even if some question my motives. I am sure the same goes for many who are interested in a fair record hunt.

Cheers,
Martin

So let me see if I have this right. The WSSRC introduced extreme water depth rules, these were appealed, the rules were amended and kitesurfers broke the overall speed record.

The WSSRC commissioned a report and used it to set a water depth rule which was challenged and amended allowing the kiters to break the outright speed record.

ISAF initially didn't recognise kiters for the overall record but the WSSRC, IWSC and IKA stepped in to champion their cause and had the objections overturned allowing kiters to hold the overall speed record.

The kiters have the advantage based on their size and range of conditions they can run in, yachts have to run in deeper choppier water and windsurfers are just too slow now with current technology to compete for top honours. I don't see how the small craft like kites and windsurfers are disadvantaged by the WSSRC rules, or again am I missing something.

So again I ask what is this fight really about? It seems Martin sees injustices that don't exist other than in his mind and he is hell bent on fighting for them anyway. I wish him good luck and look forward to him claiming the "fastest gps 10 second sailor in the world using 2 handheld GT-31 GPS units with xxxx firmware analysed by GPS xxxx software".

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Roo said...

I wish him good luck and look forward to him claiming the "fastest gps 10 second sailor in the world using 2 handheld GT-31 GPS units with xxxx firmware analysed by GPS xxxx software".

correct - and I wish the WSSRC-yachting club, who has no idea about kiting, good luck when claiming their funny video-timed 500-m-nonsense-records

And as always rightful questions remain unanswered by those who bow for an institution which stands above the law.

Seems the question was aked of some Hydrodynamic experts and this is their reply: hydrocompmusings.wordpress.com/2009/03/20/time-trial-racing-deep-water-versus-shallow-water/

Essentially running in shallow water does reduce drag and increase speed. The author thought everyone should run in shallow water as speed would increase through reduced drag, cleaner wind and less chop. Unfortunately only kites can run in the shallow water where this would be an advantage.

I think you meant to say:

"fortunately, kites can run in the shallow water where this would be an advantage."

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Roo said...

........edit.......I don't see how the small craft like kites and windsurfers are disadvantaged by the WSSRC rules, or again am I missing something..............

Again, the answer is yes.
Small craft are disadvantaged by a exorbitantly expensive and restrictive set of costs and rules that means the vast majority can't afford to compete and be compared. This makes the WSSRC records far less creditable. (see my example in a previous post). Only super rich or highly sponsored guys can set them. It is not down to how fast a particular individual can go when conditions are optimal but how much they can afford to pay and then be able to run when conditions are optimal. In other words, WSSRC world records often go to those who simply have the money to buy them.

"In other words, WSSRC world records often go to those who simple have the money to buy them."

I'm sure Alex, Antoine, Finian, Tim and Simon, Eric and Pascal would all appreciate you saying they bought their records!

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Roo said...
Unfortunately only kites can run in the shallow water where this would be an advantage.

...not true.
Add two or three 20-cm-fins to a 1m wide course race board and you can ride on 30 cm deep water using the ground effect, as 30 cm is less than half the beam of the board.

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Roo said...

"In other words, WSSRC world records often go to those who simply have the money to buy them."

I'm sure Alex, Antoine, Finian, Tim and Simon, Eric and Pascal would all appreciate you saying they bought their records!

I didn't say that Roo. You are the one who suggests it. But I may agree with you on some of them......

Do you even understand the concept behind my statement?