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Moth on Foils: 10 sec. average: 35.9 knots(41.29mph)!

Peak: 36.6 knots( 42.09mph)

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#1 Doug Lord

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Posted 13 May 2014 - 09:18 PM

Astonishing effort by Ned Goss in Charelston!!!

http://www.foilingwe...leston-bay-usa/

 

Just when I thought the Flying Phantom was catching up.....



#2 bloodshot

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Posted 13 May 2014 - 09:22 PM

kudos to Ned.  one of my former junior sailors, though I can't say my teachings had any influence on this accomplishment!



#3 gui

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Posted 13 May 2014 - 11:49 PM

Astonishing effort by Ned Goss in Charelston!!!
http://www.foilingwe...leston-bay-usa/
 
Just when I thought the Flying Phantom was catching up.....


if only he could turn ;)

nice job Ned!

#4 fastyacht

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Posted 14 May 2014 - 01:43 AM

Finally, a record that matches MONITOR. From 1950s.



#5 Doug Lord

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Posted 14 May 2014 - 02:06 AM

What do you mean by finally? Monitor was 26' long , 21' wide(including foils) and weighed 800 pounds compared to an 11' X 7', 65lb Moth?

Monitor was an incredible sailing machine but needed wind over 13 knots to take off or she had to be towed. She could tack and gybe on foils and was estimated to foil at two times windspeed. The foils, through a mechanical computer, controlled RM as well as vertical lift. Control of her rear foil was through the mechanical computer. Her "official" highest speed was 30.5 knots and unofficially 40+ knots.

I guess the really significant thing is that no sailboat the size of the Moth has ever come close to Goss's speed......



#6 fastyacht

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Posted 14 May 2014 - 02:19 AM

Finally, a small hydrofoil that actually works and goes that fast. 

 

It's amazing how long it took. Without the moth class allowing what they allowed, I bet we'd still be a long way off.  Williwaw and before it, Monitor, and a few others, showed it was possible but for whatever reason, it just didn't stick. The moth, racing in sizeable fleets, by 2007 had changed everything.



#7 teknologika

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Posted 14 May 2014 - 07:02 AM

How much tide?

#8 mustang__1

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Posted 14 May 2014 - 03:53 PM

How much tide?

was just about to ask that. 



#9 Doug Lord

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Posted 14 May 2014 - 03:59 PM

According to Goss, he had adverse current on his record run......see SA front page for more.



#10 MR.CLEAN

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Posted 14 May 2014 - 04:18 PM

Finally, a small hydrofoil that actually works and goes that fast. 

 

It's amazing how long it took. Without the moth class allowing what they allowed, I bet we'd still be a long way off.  Williwaw and before it, Monitor, and a few others, showed it was possible but for whatever reason, it just didn't stick. The moth, racing in sizeable fleets, by 2007 had changed everything.

 

Apples to bananas?

 

Monitor was outfoiled, first, by Hydroptere many, many years ago, and the line of foilers that ended with Vestas Sailrocket V.2.  The Moth is a box/development rule class racing boat.  



#11 MR.CLEAN

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Posted 14 May 2014 - 04:20 PM

I spoke to Ned for an hour last night.  Yes to adverse current; we haven't done the vectors but probably a bit more than a knot in that spot at that time. 

 

Also, he put himself in a spot where nice bullets come down over James Island and hit the water, which is dead flat there.  Ned got into the waves so quickly and hit one, knocking himself off the back of the boat and giving himself a nasty bruise, solely from the force of hitting the water at 40 mph.



#12 couchsurfer

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Posted 14 May 2014 - 04:38 PM

.......... Ned got into the waves so quickly and hit one, knocking himself off the back of the boat and giving himself a nasty bruise, solely from the force of hitting the water at 40 mph.

.

......good he didn't hit a kelp patch!!  :mellow:  :blink:  :rolleyes:



#13 teknologika

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Posted 14 May 2014 - 08:09 PM

This claim is no less valid than anyone else's. That said it is such a big jump, he should make the file available for public scrutiny.

#14 mad

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Posted 14 May 2014 - 08:23 PM

Has Dougy built his 'peoples foiler' yet???

#15 Velocitek

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Posted 15 May 2014 - 03:21 AM

@teknologika - We have a new post up on the Velocitek Blog, The Speed Read about Ned Goss's speed run. While much of the content reused from the front page, we did mine the raw GPS data for the speeds to show you when things started to get interesting. Check out the post here: http://blog.velocitek.com/?p=1393

 

A screenshot of the top speed GPS data from Ned's run is attached to this post.

 

 

Attached Files



#16 barney

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Posted 15 May 2014 - 06:43 AM

A screenshot of the top speed GPS data from Ned's run is attached to this post.

 

The ProStart can measure the speed at 2Hz, too bad it only logs the trackpoints just every two seconds.



#17 RobG

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Posted 15 May 2014 - 12:47 PM

A screenshot of the top speed GPS data from Ned's run is attached to this post.

 

The ProStart can measure the speed at 2Hz, too bad it only logs the trackpoints just every two seconds.

They update the speed reading at 0.5 seconds, they take hugely more measurements than that.

 

I doubt that more frequent logs would reveal any greater accuracy, there'd just be more noise. Unless you're more of a mathematic genius than the guys who write the software for these things and can resolve a more accurate position from fewer measurements.

 

If you want more data points, interpolate them from what is provided.

 

Interesting that there's a 32 second gap in the data between 12:17:54 and 12:18:28.



#18 MR.CLEAN

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Posted 15 May 2014 - 01:05 PM

@teknologika - We have a new post up on the Velocitek Blog, The Speed Read about Ned Goss's speed run. While much of the content reused from the front page, we did mine the raw GPS data for the speeds to show you when things started to get interesting. Check out the post here: http://blog.velocitek.com/?p=1393

 

A screenshot of the top speed GPS data from Ned's run is attached to this post.

 

Very cool.  Thanks, guys!



#19 BrianM

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Posted 15 May 2014 - 01:34 PM

Interesting that there's a 32 second gap in the data between 12:17:54 and 12:18:28.

I figure that's when the ProStart was under water.  Speed went from 36.8 kts to 1.5 kts...and he apparently ended the run with an ejection off the aft end.  Boat sans pilot capsizes, GPS drops track until it surfaces.



#20 RobG

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Posted 15 May 2014 - 03:28 PM

Interesting that there's a 32 second gap in the data between 12:17:54 and 12:18:28.

I figure that's when the ProStart was under water.  Speed went from 36.8 kts to 1.5 kts...and he apparently ended the run with an ejection off the aft end.  Boat sans pilot capsizes, GPS drops track until it surfaces.

 

Yes, seems reasonable.



#21 couchsurfer

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Posted 15 May 2014 - 07:11 PM

....maybe the gap was when they were passing it from the powerboat :mellow:



#22 Phil S

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Posted 15 May 2014 - 10:01 PM

There is a lot here which does not add up.

Mostly that a lot of fast moth sailors who actually go to big regattas and spend a lot of time sailing, all using similar or known faster equipment (like smaller rudder foils, low drag tramps, and higher speed foils like the Macita) have never been within 4 kts of this speed.

I am not saying its a fake just that something does not add up. Does the venue have some secret CIA site emitting spurious signals to confuse the ProStart? There just was not enough power in 20kt winds. Maybe he got a 35kt gust off the land but that would be unlikely to last 10 seconds. The Velocitek record seems to indicate that he spent more time over 30kts than the cumulative total of everyone who has beaten that record to date. Something has to be wrong.

Either that or these gadgets are just not as reliable as we all thought, in which case I will never trust my Speed Puck readings again.



#23 teknologika

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Posted 15 May 2014 - 10:27 PM

There is a lot here which does not add up.
Mostly that a lot of fast moth sailors who actually go to big regattas and spend a lot of time sailing, all using similar or known faster equipment (like smaller rudder foils, low drag tramps, and higher speed foils like the Macita) have never been within 4 kts of this speed.
I am not saying its a fake just that something does not add up. Does the venue have some secret CIA site emitting spurious signals to confuse the ProStart? There just was not enough power in 20kt winds. Maybe he got a 35kt gust off the land but that would be unlikely to last 10 seconds. The Velocitek record seems to indicate that he spent more time over 30kts than the cumulative total of everyone who has beaten that record to date. Something has to be wrong.
Either that or these gadgets are just not as reliable as we all thought, in which case I will never trust my Speed Puck readings again.


Agree 100%.

GPS speed over ground readings always have an element of doubt as they do not reflect true boat speed. There should have been other runs on the same day at a similar speed, so lots of runs in the low 30's. Was there ?

Looking at the headings, there is a lot of variation for someone doing 36 knots but I put that down to the low frequency of data points.

#24 Doug Lord

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Posted 15 May 2014 - 11:20 PM

Interesting no "expert" has mentioned Neds weight-202lb. Might be a hindrance in course racing but maybe not in getting the most out of those conditions? The last two posts seem kind of pathetic.......course I could be wrong.

 

from frnt page:

 

Wind speed: 18-22 Gust to 25
Wind Direction: SSE
Sea state: Dead flat at start of run
Skipper Weight: 202 lbs.
Height: 6′

 



#25 Shu

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Posted 16 May 2014 - 12:30 AM

There is a lot here which does not add up.

Mostly that a lot of fast moth sailors who actually go to big regattas and spend a lot of time sailing, all using similar or known faster equipment (like smaller rudder foils, low drag tramps, and higher speed foils like the Macita) have never been within 4 kts of this speed.

I am not saying its a fake just that something does not add up. Does the venue have some secret CIA site emitting spurious signals to confuse the ProStart? There just was not enough power in 20kt winds. Maybe he got a 35kt gust off the land but that would be unlikely to last 10 seconds. The Velocitek record seems to indicate that he spent more time over 30kts than the cumulative total of everyone who has beaten that record to date. Something has to be wrong.

Either that or these gadgets are just not as reliable as we all thought, in which case I will never trust my Speed Puck readings again.

How many of the these fast moth sailors go out regularly in search of pure speed?  I suspect they are spending most of their time working on that elusive vmg.  A big gust in flat water can produce astonishing speed in planing dinghies, why not for one on foils?



#26 Phil S

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Posted 16 May 2014 - 01:09 AM

This data is what velocitec uploaded:

http://blog.velocite...ss-VCC-Text.png

The line with the 36.196kts is at heading 75.72deg which is pretty remarkable when the reported wind direction was SSE or 157.5deg. Beam reaching a moth is known as the death angle and is rarely as fast as deep reaching.

Also the plot on Velocitek Blog does not show any tracks in that direction.

 Ned-Goss-Strava-GPX.png

Can anyone explain?



#27 RobG

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Posted 16 May 2014 - 03:00 AM

Put one of the coordinates into Google Maps: https://maps.google....793518&t=h&z=15

 

Seems to be the run at the top right, which is about the right angle. The differences in heading are likely just noise in the data, GPS devices aren't as accurate as most think, readings are generated from many, many individual measurements.

 

For example, the coordinates in the log are to 15 decimal places of a degree, which is less than a nanometre.No one thinks the readings are that accurate.

 

The 32 second loss of data should be explained, I've had plenty of crashes where a Speed Puck has not lost lock, and also cases where it's lost lock for no apparent reason. This data has been processed, so there should be a rational explanation for why it is how it is.



#28 duncan (the other one)

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Posted 16 May 2014 - 03:50 AM

The last two posts seem kind of pathetic.......

Hardly.. they're from two of the few people on this thread who have practical experience and know what they're talking about.

#29 aus2479

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Posted 16 May 2014 - 03:51 AM

There is a lot here which does not add up.

Mostly that a lot of fast moth sailors who actually go to big regattas and spend a lot of time sailing, all using similar or known faster equipment (like smaller rudder foils, low drag tramps, and higher speed foils like the Macita) have never been within 4 kts of this speed.

I am not saying its a fake just that something does not add up. Does the venue have some secret CIA site emitting spurious signals to confuse the ProStart? There just was not enough power in 20kt winds. Maybe he got a 35kt gust off the land but that would be unlikely to last 10 seconds. The Velocitek record seems to indicate that he spent more time over 30kts than the cumulative total of everyone who has beaten that record to date. Something has to be wrong.

Either that or these gadgets are just not as reliable as we all thought, in which case I will never trust my Speed Puck readings again.

How many of the these fast moth sailors go out regularly in search of pure speed?  I suspect they are spending most of their time working on that elusive vmg.  A big gust in flat water can produce astonishing speed in planing dinghies, why not for one on foils?

 

I'd say all of the fast moth sailors would have had a crack at pure speed in similar breeze strengths or greater in the 5 or so years the mach 2 has been out.  However as Phil says no one is within 4 knots with speed only increasing by around 3 knots in that whole time, come on unless there is some other factor at play it is most likely a false reading.  However it is just as valid as anyone else who has claimed a top speed in the moth so there is no choice but to give the man the record.   



#30 couchsurfer

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Posted 16 May 2014 - 05:30 AM

 

There is a lot here which does not add up.

Mostly that a lot of fast moth sailors who actually go to big regattas and spend a lot of time sailing, all using similar or known faster equipment (like smaller rudder foils, low drag tramps, and higher speed foils like the Macita) have never been within 4 kts of this speed.

I am not saying its a fake just that something does not add up. Does the venue have some secret CIA site emitting spurious signals to confuse the ProStart? There just was not enough power in 20kt winds. Maybe he got a 35kt gust off the land but that would be unlikely to last 10 seconds. The Velocitek record seems to indicate that he spent more time over 30kts than the cumulative total of everyone who has beaten that record to date. Something has to be wrong.

Either that or these gadgets are just not as reliable as we all thought, in which case I will never trust my Speed Puck readings again.

How many of the these fast moth sailors go out regularly in search of pure speed?  I suspect they are spending most of their time working on that elusive vmg.  A big gust in flat water can produce astonishing speed in planing dinghies, why not for one on foils?

 

I'd say all of the fast moth sailors would have had a crack at pure speed in similar breeze strengths or greater in the 5 or so years the mach 2 has been out.  However as Phil says no one is within 4 knots with speed only increasing by around 3 knots in that whole time, come on unless there is some other factor at play it is most likely a false reading.  However it is just as valid as anyone else who has claimed a top speed in the moth so there is no choice but to give the man the record.   

.

...it's possible that Ned's weight might have helped,no?

.....perhaps the extra weight,,,carving along at the 'death-angle' could achieve something special



#31 Phil S

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Posted 16 May 2014 - 05:53 AM

202lb is only 91 kg, not that heavy. There are a few very fast moth sailors heavier than that who have not done 31kts yet, and they have been trying, in much more wind too.



#32 teknologika

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Posted 16 May 2014 - 06:25 AM



There is a lot here which does not add up.
Mostly that a lot of fast moth sailors who actually go to big regattas and spend a lot of time sailing, all using similar or known faster equipment (like smaller rudder foils, low drag tramps, and higher speed foils like the Macita) have never been within 4 kts of this speed.
I am not saying its a fake just that something does not add up. Does the venue have some secret CIA site emitting spurious signals to confuse the ProStart? There just was not enough power in 20kt winds. Maybe he got a 35kt gust off the land but that would be unlikely to last 10 seconds. The Velocitek record seems to indicate that he spent more time over 30kts than the cumulative total of everyone who has beaten that record to date. Something has to be wrong.
Either that or these gadgets are just not as reliable as we all thought, in which case I will never trust my Speed Puck readings again.

How many of the these fast moth sailors go out regularly in search of pure speed?  I suspect they are spending most of their time working on that elusive vmg.  A big gust in flat water can produce astonishing speed in planing dinghies, why not for one on foils?
 
I'd say all of the fast moth sailors would have had a crack at pure speed in similar breeze strengths or greater in the 5 or so years the mach 2 has been out.  However as Phil says no one is within 4 knots with speed only increasing by around 3 knots in that whole time, come on unless there is some other factor at play it is most likely a false reading.  However it is just as valid as anyone else who has claimed a top speed in the moth so there is no choice but to give the man the record.   
So can Luka claim his 50 knot peak then? :-)

There is another explanation. That is people have just stopped clamping the speed even if they have gone faster.

#33 aus2479

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Posted 16 May 2014 - 07:22 AM




There is a lot here which does not add up.
Mostly that a lot of fast moth sailors who actually go to big regattas and spend a lot of time sailing, all using similar or known faster equipment (like smaller rudder foils, low drag tramps, and higher speed foils like the Macita) have never been within 4 kts of this speed.
I am not saying its a fake just that something does not add up. Does the venue have some secret CIA site emitting spurious signals to confuse the ProStart? There just was not enough power in 20kt winds. Maybe he got a 35kt gust off the land but that would be unlikely to last 10 seconds. The Velocitek record seems to indicate that he spent more time over 30kts than the cumulative total of everyone who has beaten that record to date. Something has to be wrong.
Either that or these gadgets are just not as reliable as we all thought, in which case I will never trust my Speed Puck readings again.

How many of the these fast moth sailors go out regularly in search of pure speed?  I suspect they are spending most of their time working on that elusive vmg.  A big gust in flat water can produce astonishing speed in planing dinghies, why not for one on foils?
 
I'd say all of the fast moth sailors would have had a crack at pure speed in similar breeze strengths or greater in the 5 or so years the mach 2 has been out.  However as Phil says no one is within 4 knots with speed only increasing by around 3 knots in that whole time, come on unless there is some other factor at play it is most likely a false reading.  However it is just as valid as anyone else who has claimed a top speed in the moth so there is no choice but to give the man the record.   
So can Luka claim his 50 knot peak then? :-)

There is another explanation. That is people have just stopped clamping the speed even if they have gone faster.

I haven't looked at the track but if you have a track that shows you sailing downwind at a consistent speed then its just as valid as the claims before. I won't claim my 200 knots nor should anyone else where it's obvious spike.

#34 dogwatch

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Posted 16 May 2014 - 08:21 AM

The ProStart can measure the speed at 2Hz, too bad it only logs the trackpoints just every two seconds.

GPS doesn't measure speed, it measures position. 10 seconds @ 35 knots is approx 20 metres. GPS accuracy is 2-3 metres. OK, errors tend to be correlated so is velocity not as uncertain as those errors might imply but even so, big claims based on a 20 metre run? Seriously?

#35 Clipper

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Posted 16 May 2014 - 08:57 AM

Might pay to check your maths. 10 seconds at 35 knots must be closer to 180m off top of my head

#36 duncan (the other one)

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Posted 16 May 2014 - 08:57 AM

The ProStart can measure the speed at 2Hz, too bad it only logs the trackpoints just every two seconds.

GPS doesn't measure speed, it measures position. 10 seconds @ 35 knots is approx 20 metres. GPS accuracy is 2-3 metres. OK, errors tend to be correlated so is velocity not as uncertain as those errors might imply but even so, big claims based on a 20 metre run? Seriously?

 

ahem.. think you forgot an order of magnitude there.

 

35kn ~ 18m/s.  So 10s = 180m



#37 dogwatch

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Posted 16 May 2014 - 10:09 AM

^

This is true.

#38 RobG

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Posted 16 May 2014 - 10:53 AM

GPS speed over ground readings always have an element of doubt as they do not reflect true boat speed.

 

Fair point, but World Sailing Speed Record Council records are measured "over the ground" using time to cover a measured distance or total distance in a specified time. It would be good if relevant tide and wind data were also published.



#39 fastyacht

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Posted 16 May 2014 - 10:56 AM

Just do the error bounds on the positions.



#40 couchsurfer

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Posted 16 May 2014 - 12:45 PM

.

....what would jesus the WSSR say?....do they have a basic criteria for GPS records? :mellow:

                      .......could it be a critical error to not have the go-pro running on this 'attempt'? :unsure:

 

 

...and Ned--is he taking this seriously?...haven't seen him around,,,it seems like everyone may be taking this 'claim' more seriously than -he- is(?)  :huh:



#41 fireball

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Posted 16 May 2014 - 01:19 PM

Wouldn't you need the dilution of position values at the time of the run before you get excited about the claimed speeds?

There are going to be some cases where these gps units give very inaccurate estimates of boat speed. Maybe this was one of them.

#42 ortegakid

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Posted 16 May 2014 - 02:45 PM

Whatever, it's freakin fast, I skyski at 16-18, 22 max and it hurts when you hit the water, can only imagine what 40 feels like!



#43 fastyacht

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Posted 16 May 2014 - 04:48 PM

In other words, dilution of precision due to bad satellite locations/occlusion.

 

 

https://www.e-educat...nfo/c5_p21.html



#44 BrianM

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Posted 19 May 2014 - 03:52 PM

Got bored and played with numbers.  (fed the Velocitek PNG to Excel and did my own math).  GPS position accuracy is advertised as 2.199m at 95% confidence, which means about 6% of the distances involved between marks for the 34+kn portion of this run.  So if we assume the position data is correct:

 

For the most part, the reported speed/heading are consistent with the position data - computed speed averages 94% of recorded speed for most of the data (min 79%, max 111%); starts the speed run with computed 36.41 knts when the trace shows 33.98, ends at 32.55 when the tracks shows 36.75.  But something odd shows up between 12:17:54 and 12:18:28 (the missing 32 seconds).  Basically, until that point the track is generally north-east (~075) - then takes a huge step back southwest (moves ~390 yards down 200 degrees, recorded as heading 064) and drops to 1.5 knots.

 

I still believe the speed drop is the capsize, but the location makes no sense.  If the capsize happens at the end of the speed run (12:17:54), GPS drops track while underwater, then regains once the boat is right-side up again, you have to make almost 21 knots (while capsized) in the opposite direction to get to the 'capsize recovery point' on time (12:18:28).

 

Hummm.

 

Or did I do something stupid math-wise?



#45 Rasputin22

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Posted 19 May 2014 - 04:04 PM

I use a couple of different soaring apps on Garmin road navigation units and on a HTC phone as well as Iphone. They seem to have very good filtering algorithms to weed out spurious data and I don't see many wild peaks in speed and position. What is amazing is the ability of these apps to compute the relatively small altitude loss and gains and predict just how far one can glide from your present altitude and display it on the terrain below with a sort of polar plot. The app calls this 'range' function the 'amoeba' and that is just what it looks like. When you do a 360 to enter a thermal to gain altitude, it will calculate set and drift due to wind and drop a point indicating the center of the thermal after the first turn. After exiting the thermal and heading out looking for the next, it will keep that now known and plotted thermal marker and you can always come back and hope a fresh thermal has formed at that spot. Kind of like stepping stones and a good thing to know late in the afternoon when returning from a cross country and the sun is getting lower in the sky and the dynamics of thermal flight are waning. I've often thought about contacting the open source group that has developed this soaring app and point them in the direction of applying some of their tricks to a sailing app.

 

http://www.xcsoar.org/



#46 ians

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Posted 20 May 2014 - 06:46 PM

Does anyone know how the Velocitek calculates speed anyway?

Are the positions differentiated, or is there something smarter like Kalman Filtering?

 

also: it displays and records at 2Hz. Is that the raw sampling rate? Or is this the fit position of a dynamic model?



#47 RobG

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Posted 21 May 2014 - 11:20 AM

[…]

Or did I do something stupid math-wise?

 

You haven't shown your working, but I don't think so. I tried to attach an MS Excel spread sheet but couldn't so I've pasted the data below for those who want to try on their own. Formulae for computing the distances are easy to find, I've pasted two below.

 

 

Date,Time,Heading,Speed,Latitude,Longitude
2014-05-10,12:17:27, 55.71, 4.898,32.773220062255859,-79.922195434570312
2014-05-10,12:17:29, 72.36,11.276,32.773250579833984,-79.922073364257812
2014-05-10,12:17:31, 64.64,12.583,32.773300170898438,-79.921951293945312
2014-05-10,12:17:33, 53.88,19.881,32.773403167724609,-79.921821594328281
2014-05-10,12:17:35, 59.36,22.420,32.773494720458984,-79.921661376953125
2014-05-10,12:17:37, 65.27,26.627,32.773620605468750,-79.921371459960938
2014-05-10,12:17:39, 75.27,33.983,32.773700714111328,-79.920982360839844
2014-05-10,12:17:41, 72.31,33.939,32.773803710937500,-79.920616149902344
2014-05-10,12:17:43, 70.85,34.339,32.773918151855469,-79.920265197753900
2014-05-10,12:17:45, 76.67,35.741,32.773971557617188,-79.919876098632812
2014-05-10,12:17:47, 75.72,36.196,32.774032592773438,-79.919502258300781
2014-05-10,12:17:49, 72.30,35.445,32.774085998535156,-79.919189453125000
2014-05-10,12:17:54, 64.20,36.757,32.774490356445312,-79.918434143066400
2014-05-10,12:18:28, 64.71, 1.525,32.773368835449219,-79.922088623046875
2014-05-10,12:18:30, 70.20, 1.463,32.773368835449219,-79.922073364257812
2014-05-10,12:18:32,118.81, 2.538,32.773357391357422,-79.922058105468750
2014-05-10,12:18:34,116.30, 2.401,32.773345947265625,-79.922035217285156
2014-05-10,12:18:36,118.09, 4.471,32.773330688476562,-79.921997070312500
2014-05-10,12:18:38,119.34, 7.964,32.773300170898438,-79.921928405761719
 
Lat and long in degrees:
=ACOS(SIN(lat1*PI()/180)*SIN(lat2*PI()/180)+COS(lat1*PI()/180)*COS(lat2*PI()/180)*COS(lon2*PI()/180-lon1*PI()/180))*r
 

Lat and long in radians (deg*pi/180):

=2*ASIN(SQRT(POWER(SIN((lat1-lat2)/2),2)+COS(lat1)*COS(lat2)*POWER(SIN((lon1-lon2)/2),2)))*r

 
Earth radius: 6371000m


#48 BrianM

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Posted 21 May 2014 - 02:03 PM

You haven't shown your working, but I don't think so.

Earth radius: 6371000m

Excellent point...  My data below, given as a comma-separated value file (.csv) read in 11 columns.  Only showing the bit o' interest between 12:17:37 and 12:18:28.  I force-rounded the lat/long positions to five decimal places (approximates the ~1m accuracy of GPS), but that didn't really change anything. 

 

Calc dist (yds) generated using

=ACOS(SIN(Lat1)*SIN(Lat2)+COS(Lat1)*COS(Lat2)*COS(Long2-Long1))*radius
with lat/long in radians and radius of 3443.898 nautical miles.  The result is actually in NM, converted using 2000 yds/NM.


Calc heading
=DEGREES(ATAN2(COS(Lat1)*SIN(Lat2)-SIN(Lat1)*COS(Lat2)*COS(Long2-Long1), SIN(Long2-Long1)*COS(Lat1)))

 

spd delta = calc speed - Vtek speed

% spd delta = calc speed / Vtek speed

hdg delta = calc hdg - Vtek hdg

 

Time,Vtek Heading,Vtek Speed,Lat (deg/rd),Long (deg/rd),Calc dist (yds),Calc speed,spd delta,% spd delta,Calc hdg,hdg delta
12:17:37,65.27,26.63,32.77362,-79.92137,33.22,29.897,3.270,112%,61.94,-3.33
12:17:39,75.27,33.98,32.7737,-79.92098,40.58,36.519,2.536,107%,76.29,1.02
12:17:41,72.31,33.94,32.7738,-79.92062,38.32,34.490,0.551,102%,71.72,-0.59
12:17:43,70.85,34.34,32.77392,-79.92027,38.21,34.385,0.046,100%,67.82,-3.03
12:17:45,76.67,35.741,32.77397,-79.91988,39.88,35.889,0.148,100%,81.33,4.66
12:17:47,75.72,36.196,32.77403,-79.9195,39.08,35.173,-1.023,97%,79.36,3.64
12:17:49,72.3,35.445,32.77409,-79.91919,32.15,28.938,-6.507,82%,77.04,4.74
12:17:54,64.2,36.757,32.77449,-79.91843,90.63,32.626,-4.131,89%,57.95,-6.25
12:18:28,64.71,1.525,32.77337,-79.92209,393.69,20.842,19.317,1267%,200.00,-174.71

The odd bit I mentioned is in the last line.  Vtek speed = 1.525 kts, calc speed = 19.317; Vtek hdg = 064 degrees, Calc hdg = 200.  The remaining latitude marks after that time are consistent with the 18:28 position (32.77337), a huge jump backward from the previous spots (32.7744ish).



#49 MR.CLEAN

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Posted 21 May 2014 - 03:12 PM

No one takes moth speed records seriously, but they sure are fun.

 

Ned didn't tell anyone about this until Alec @ Vtek and Bora went over the data and said it looks good.

 

Of course he could have just been on a jet ski but that ain't Ned, who is so honest he gets in trouble for it.



#50 RobG

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Posted 21 May 2014 - 11:49 PM

No one's criticising Ned, he got some data and reported it. As has been said, his claim is no less valid that anyone else's in the same circumstance.

 

The data presented has been reduced from the actual observations so all we can do is check that it's consistent with itself. Not really surprising that it is, almost.

 

There remains a question about what happened immediately after the run. It's possible that the GPS lost lock and started seeking while he gybed or tacked and foiled back to the start. But factor in the  time to recover from a capsize at speed where he was separated from the boat and that scenario seems implausible, there isn't enough time.

 

There may be a simple explanation, but we haven't heard it.






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