Darryl,
You should realize that I'm not some hack here. My field is control engineering and sensor offsets or non linearity is such a serious factor that we continiously account for that. To put it in simple terms. No sensor is truly accurate of dependable. Most of the time you only get accuracy by devising a methode that subtracts the error from the desired result. I'm sure that landsurveying technics are based on the same principle. Why simply because you can't make tools THAT accurate and not spend heaps and heaps of money. Often the same result can be achieved for far less cost if you are just smart in the way you do it.
Also you reply is both wrong and misguiding in several points. I'm sorry that I have to say that.
Any, "recognised" speed run has to be set up with a fully SURVEYED distance of the course to sub millimetre accuracy, using "light beams" (generally laser) set at 90 degrees across the course at both the start and finish of the "run". These beams are connected to a very precise timing device that is automatically activated when the vessel “breaks” them.
Do some landsurveying on the sea, please Darryl. Not having a stationary point there makes things difficult. Also you can set up those lasers on the water for the same reasons; so they have to be set-up on some nearby land. In most cases this can easily be some distance away for it is difficult to have the wind blow strongest near land or have it blow in exactly at the right angle to the land.
No I REALLY want to see ANYONE point out a location TO THE SUB MILLIMETER with complications like that. YOU may THINK that you are accurate the sub milimeter because that is what you've been told or that is what the tool says but that DOESN'T mean you are accurate the that level. Will have have to set up you beamer to at least 1/1000 of a sub millimeter to get that accuracy at say 1000 meters away. You CAN'T do that out there in the open. Hell the elasticity in the tripod and its footing (soil, dirt) will cause a greater deflection when the tripod is experiencing a gust. I know of cases where a man standing next to measurement setup caused enough deflection in the earth to cause an unacceptable off set. Yes the ground is an elastic body as well and WILL deflect under weight bringing the tripod with it.
Besides you method is totall misguided. What if the wind is so aligned that the fastest heading is say 1 or 2 degrees of the surveyed track ? THAT will give a far greater error still. In short it is IMPOSSIBLE for a sailing crew to closely approximate the layed out straight track. Also your method assumes that teh surveyer knows exactly (to the same accuracy) what the optimal speed heading is. I doubt that very much. GPS on the other hand lets the crew decide and just records.
I dare say that a GPS unit with tracking (storing location points in memory) can easily be MORE accurate in determining the highest average speed over 500 mtr than you method. I even consider it. Simply because of the limitations described above.
Why do you think that the organizations that are responsible for determining the accuracy of "official", so called "speed records" don't just take the easy way out that is being promoted here, and just use a GPS reading?
I've met more than a few people out there that are simply dumb. Engineers and scientist are also just people. I've been dumb on several occasions so I have no illusions there but it has taught me to look closely at what is at hand. The best lesson I got was when I was shown and realize that accuracy is frightingly dependend on side conditions and often alot less than your tool says or claims. True accuracy comes from smart measuring methodes.
Do you imagine for one minute that the GPS system hasn't been fully investigated for this purpose? Fair suck of the sausage, those people are professionals and their results have to be "beyond reproach".
And it IS being used in record verification. How else do YOU think they determine 24 hour distance records ? You never know when and where you are going to break that. Lasers and such are old technologies of a pre-GPS time, but now time has moved on and we have more options. Slowly these will be introduces in the various area's. Besides GPS is more and more used in landsurveying as well. If it is good enough there !
If you want a "comparative" speed reading over some distance or other, then, by all means, use a GPS reading, but it will not be anywhere near accurate enough to rate against any "official" record, regardless of how hard anyone "pushes that barrow". Any GPS readings, especially for distance covered over time, are just too “subjective” and fall down badly when objectively analysed.
This is just nonsense Darryl. Quite frankly; your laser method falls down quicker. Sorry.
And the fact that GPS is a new technique doesn't mean that the old technique is more accurate.
Wouter
