Forums > Windsurfing   Gps and Speed talk

High Altitude Sailing

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Created by Bilabog > 9 months ago, 21 Jul 2009
Bilabog
NSW, 211 posts
21 Jul 2009 9:43PM
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Could you achieve higher speeds sailing in the same wind contitions on high altitude lakes in Australia? ( as we do at sea level )


eg: Great Lake Tasmania 1030 metres above sea level.
Highest lake in Australia is Lake Cootapatama 2050 metres above sea level.
Has anyone sailed at High Altitude?

Mobydisc
NSW, 9029 posts
21 Jul 2009 9:47PM
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I sailed a few dams around Armidale, altitude on one dam up near Guyra would be over 1000 meters. Winds were extremely gusty, it was freezing cold and the runs were short.

I don't think altitude had much of an influence on the sailing more than the above factors and the fresh water.

Bilabog
NSW, 211 posts
21 Jul 2009 10:16PM
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Highest navigatable lake in the world is Lake Titicaca in Peru South America.
3820 metres above sea level. Would be interesting to see at that altitude if it made a difference in speed.

Bilabog
NSW, 211 posts
21 Jul 2009 10:19PM
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Bilabog
NSW, 211 posts
21 Jul 2009 10:46PM
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May be 1000 metres is not enough altitude to notice with out using a gps. At 3,000 metres you should be able to tell. At 3,000 metres there should be alot less fiction with the thinner air. When they have Olympic Games at high altitudes they get better times. So the same principal should count maybe?The winds also are high speeds at altitude.

Mobydisc said...

I sailed a few dams around Armidale, altitude on one dam up near Guyra would be over 1000 meters. Winds were extremely gusty, it was freezing cold and the runs were short.

I don't think altitude had much of an influence on the sailing more than the above factors and the fresh water.


sailquik
VIC, 6168 posts
22 Jul 2009 11:03AM
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Thinner air would indeed offer less resistance, but would also offer less force acting on the sails.
I really don't know, but intuition tells me it may all cancel out.

mathew
QLD, 2143 posts
22 Jul 2009 11:56AM
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Stayed at Jindabyne caravan park when I was 15... went sailing on Lake Jindabyne -> that is at 914m... (non-plaining big board).

Ian K
WA, 4169 posts
22 Jul 2009 10:16AM
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Took a Wally out on Rocky Valley Dam Vic. - 1595 metres. Remember it well , the first time I'd ever stayed upright for more than 10 metres. Cleared 100 metres that day. Almost 30 I was.

Ian K
WA, 4169 posts
22 Jul 2009 10:56AM
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Found a density calculator on the web, the air on Rocky valley dam is 17% less dense, other things being equal. Air in Canberra at 556m is 6% less dense. Don't notice any difference.

But the fresh(ish) water in Canberra is 3% less dense than seawater and you notice that on a marginally floaty board.

yoyo
WA, 1646 posts
22 Jul 2009 3:26PM
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I'm with Andrew on this. It should balance out. Less drag but also less force so you need a bigger sail for the same lift which will also have more drag so you are back where you started. But maybe the parasitic drag will be less so there will be a net benefit.

Have a look here..

www.grc.nasa.gov/WWW/K-12/airplane/density.html

Bilabog
NSW, 211 posts
22 Jul 2009 9:50PM
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Wouldn't having less drag ( due to thinner air say on lake Titicaca at 3820 metres) make it easier to go faster as long as you have enough wind.
40 knot wind would be like eg: sailing in 30 knots at sea level.
You properly could sail in high wind speeds than at sea level with the same gear?
As long as you had enough wind you could go faster because there is less fiction to slow you down? Higher speeds if you find the flat water should be able to be reached? Jet aircraft in the jet stream with a tail wind can go alot faster.

Bilabog
NSW, 211 posts
23 Jul 2009 8:52PM
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Found some Air density tables on the net.

AusMoz
QLD, 1510 posts
24 Jul 2009 9:37PM
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From my experience of sailing on fresh and salt waters, usually Salt concentration in the water & higher temperature equals more buoyancy. Have done a few high altitude sailing days on lakes in Qld, ACT,VIC but none were high salt concentration.

The high altitude freshwater lakes seemed to have a lot of drag when sailing on them



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"High Altitude Sailing" started by Bilabog