Forums > Windsurfing   Gps and Speed talk

Daffy smashes Alpha Record!!!!!

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Created by hardie > 9 months ago, 4 Jan 2008
hardie
WA, 4129 posts
4 Jan 2008 10:26PM
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Check it: http://gpsteamchallenge.com.au/showsession.php?date=2008-01-04&team=16

Must be all the coaching I gave him while I was over there

vando
QLD, 3418 posts
4 Jan 2008 11:42PM
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wow daffy thats really lifted the bar.
congrats mate.

elmo
WA, 8868 posts
4 Jan 2008 11:15PM
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Holy Snapin Duck Poo!!!!

Thats Bloody awesome

Well done Andrew

sailquik
VIC, 6165 posts
5 Jan 2008 1:39AM
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Thanks guys

It was almost perfect conditions today to have a good go. 18-22 knots and low tide. The wind eased a bit at times and I actually felt slightly underpowered and under finned, even on my best runs so I recon there is still a bit of headroom left for me yet.

I was surprised and impressed at how quick the TM speed 26 was on a beam reach on the run in and run out.

vando
QLD, 3418 posts
5 Jan 2008 12:54AM
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Perfect

TimeMachine
89 posts
4 Jan 2008 11:59PM
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Congratulations Andrew, a truely world class result. Its great to acknowledge the gear but in Alpha Racing its more about the rider than any other category of speed sailing. Brilliant work.

What is that saying you like best, "The older I get the better I was"? Well what really applies is... "The older you get the better you are"!

Mal

nebbian
WA, 6277 posts
5 Jan 2008 12:06AM
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Funny that such a high scoring gybe could be only 450 metres or so... look at the other ones as well, one of them is only 400 metres!

Very nice though, I'm jealous

elmo
WA, 8868 posts
5 Jan 2008 12:23AM
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Bloody Nora

Theres 2x 27's there and a truck load of 26's

decrepit
WA, 12767 posts
5 Jan 2008 2:55AM
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nebbian said...

Funny that such a high scoring gybe could be only 450 metres or so... look at the other ones as well, one of them is only 400 metres!

Very nice though, I'm jealous


Yes looks like Andrew has gone back up wind and slowed down, a tad prematurely. If he'd kept the hammer down for the full 250m out it could have been 27.5.

Very nice gybe min speed of about 18.
Yeah I'm jealous as well!!!

snides8
WA, 1731 posts
5 Jan 2008 10:43AM
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great -awesome gybe Andrew the bar has been set high now!!!
would be interested to get a comment from Mal re the distance measurement as it looks unusual for a 500meter reading?

snides8
WA, 1731 posts
5 Jan 2008 11:12AM
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ok got it read the instruction manual

TimeMachine
89 posts
5 Jan 2008 1:50PM
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One of the key elements of Alpha Racing is the maximum distance value. It restricts the total distance to a set maximum that ensures the gybe is a big part of the result. The longer the distance in the Alpha division the higher the speeds will be, on average.

But it is it entirely possible and allowable to use a shorter distance than the max distance for any given division. If you can do a 30 knot Alpha over 200m, and it is your best result, then that will count for the 500m division! The problem is that it is exponentially more difficult the shorter the distance gets. Andrew's result over 400m shows he has even more gas in the tank yet, and can go even faster when he optimises the 500m available.

I expect to be updating his results again on the next big easterly...

mathew
QLD, 2133 posts
5 Jan 2008 8:54PM
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The whole idea of alpha-racing is excellent, however one of the problems with the current recommended settings is that it doesn't represent a real-world sailing scenario - not that the current settings are "wrong" but just that I think some refinement is possible, ie:

- the 500m distance is too long such that it doesn't measure your actual gybe speed, where as the 250m gives a better representation; combined withthe 50m radius, we could even shorten the distance further.

- the tighter the gybe, the less downwind loss -> with an allowance of a 50m downwind radius, it doesn't show how tight your gybes are.

- in figure-8 racing you must cross over your previous leg at some point before the next marker -> it would be great to see Realspeed have this as an option which could be enforced.

Thoughts?

Ian K
WA, 4155 posts
5 Jan 2008 10:26PM
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My thoughts were that's a mighty fine alpha, and looking at the track it would still qualify as a top 250m one. Mat's suggesting the return 50 m radius might encourage a wider gybe. To simulate figure 8 racing I suppose the computer could calculate the radius of your gybe and require that you cross tracks upwind and get to that diameter ( 2*radius) upwind of your start position to qualify. That way by gybing tightly you'd not have to go so far upwind to be in position for a similar gybe at the virtual starting buoy. Tight gybes might push gps resolution though.

Calculated Daffy's centrifugal acceleration in that gybe, at about 10 m/sec on a 25 m radius , a = v*v/r , that's 0.4 Gs. So quite a bit of G force in that gybe, can you even pull any more on a sailboard on flat water? So I think a tighter gybe would have to be slower, maybe a ~25 m arc is optimum anyway, and the current format is already simplest and best?

The other real world gybing scenario a computer could calculate is max VMG downwind for 250m point to point with one gybe - but that might not be a good thing to encourage.




decrepit
WA, 12767 posts
5 Jan 2008 11:26PM
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I don't see the need to simulate anything. If you want to do real world racing, do real world racing.

I'm very happy with this as a unique computer aided gps division in it's own right, with a whole new set of strategies to work out, to get best results.

elmo
WA, 8868 posts
5 Jan 2008 11:46PM
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mathew said...

The whole idea of alpha-racing is excellent, however one of the problems with the current recommended settings is that it doesn't represent a real-world sailing scenario - not that the current settings are "wrong" but just that I think some refinement is possible, ie:

- the 500m distance is too long such that it doesn't measure your actual gybe speed, where as the 250m gives a better representation; combined withthe 50m radius, we could even shorten the distance further.

- the tighter the gybe, the less downwind loss -> with an allowance of a 50m downwind radius, it doesn't show how tight your gybes are.

- in figure-8 racing you must cross over your previous leg at some point before the next marker -> it would be great to see Realspeed have this as an option which could be enforced.

Thoughts?


If you want true Racing Gybe analysis then you can utilize the functionality of GPSarPro.

This goes into fine detail of gybes you can also enter in marker points and go into it deeper.

The Alpha racing concept is designed solely for speed not going around "cans" and is a great concept for us straight line boys, introducing another area to attack and improve our skills.

sailquik
VIC, 6165 posts
6 Jan 2008 2:04PM
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mathew said...

The whole idea of alpha-racing is excellent, however one of the problems with the current recommended settings is that it doesn't represent a real-world sailing scenario - not that the current settings are "wrong" but just that I think some refinement is possible, ie:

- the 500m distance is too long such that it doesn't measure your actual gybe speed, where as the 250m gives a better representation; combined withthe 50m radius, we could even shorten the distance further.

- the tighter the gybe, the less downwind loss -> with an allowance of a 50m downwind radius, it doesn't show how tight your gybes are.

- in figure-8 racing you must cross over your previous leg at some point before the next marker -> it would be great to see Realspeed have this as an option which could be enforced.

Thoughts?


Nope. You are completely incorrect Mat.

Those Gybes were as 'real world' as any competition slalom gybes I have ever done unless I was severely compromised for room at the mark. Also, that is about as tight I gybe as I can pull at 30 knots. I'd like to see anyone do it tighter on a full on slalom board at that speed without severely compromising speed. Sure, I can pull it a lot tighter on my wave board but I doubt many wave boards would pull 32 knots square to the wind. The harder you carve it, the more speed you wash off with drag. But if you go too wide you spend too much time turning and slowing. There is an optimum radius for the equipment and conditions.
Almost all figure 8 slalom courses I have sailed were at least double the length of that run. More than enough space to get to speed and cross your track. On previous sessions I had done more of an Alpha shape and come back within about 10 meters proximity. This give you a slight advantage in one way. It can include more of your (usually faster) In-Run. But the diameter of the gybe was the same. In this session I tried a different tactic, coming back pretty well parallel and going for Out-Run speed and it seemed to be faster. Also remember that in downwind slalom there is usually no disadvantage in going wide in the turn and each leg is a broad reach. That is real world but would not work with our Alpha unless we made the proximity circle huge!
Remember that a really fast gybe also includes the slight bearaway to maximise speed before setting the rail. The second phase of the gybe is the tighter radius bit but as soon as the board is through he downwind position the radius should be opening out again to maintain speed and then accelerate

The 500m distance is just right IMHO. In fact, my first serious go at Alphas last year saw my 250 and 500m PB's on the same run! That was probably because I was coming back on the Out-Run too tight and upwind. Anyhow, my best 250 Alpha this day was also my 3rd best 500m Alpha and the Best 500m alpha was the second best 250. The 500m Alpha is most certainly a test of gybe speed because it does not matter how fast you get in and out, if you don't maintain speed in the turn you will be slower.

Finally, RealSpeed does give you the option of changing the Proximity circle size but that is only of use to you for your own interest or training. The standard for this competition is set at 50m (Diameter - which effectively means 25m for the turn and return) and I think that is just right. (except for the Gemini Tandem where I had to extend it to 100m (50m effective) just to get a result! :-)



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"Daffy smashes Alpha Record!!!!!" started by hardie