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mathew said..

Also, purchase of land anywhere near civilisation, will cost more than God could create in a day.

I personally know guys that own farms land in excess of thousand hectares. The problem is not really keen windsurfers ....
But maybe they could build irrigation channel one day that we could design and use ?
Eventually that is win / win situation . We don't not consume this irrigation water in the channel (sporadic peeing could go unnoticed crops don't bother), guys could do on their land whatever they want.
Maybe not exactly - as still some bureaucrat could come on the farm and request a water rights to fill in the channel.

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choco said..
More effort should be put in to developing ultra efficient sails fins and boards where speeds of 50+ knots can be done in 20-25 knots of wind

Apart from SailRocket 2, most other high-speed sailing craft are reaching the limit of speed... and it is mostly because any sailing craft is power-limited due to limited leverage.

A few years ago some of us thought we were reaching the peak of efficiency of gear (I know that I did)... but we do see some improvements across the years... so there may be some merit in that.

eg: better construction materials such diamond-nanothreads... www.scientificamerican.com/article/liquid-benzene-squeezed-to-form-diamond-nanothreads/

I look forward to what we will learn in the next few years...!

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hardie said..

sailquik said..


This Place has some remarkable similarities to Luderitz, not the least of which is that they are both a long way from anywhere....

I recon a canal dug in the salt flats near Denham would have much steadier wind than Luderitz! Mal Wright, who spent his teen years there, tells me the wind can really blow hard quite regularly.

How long is Luderitz channel and what is average width and depth ?Is it already ideal shape, length and width or sailors may wish for some improvements ?

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Macroscien said..

How long is Luderitz channel and what is average width and depth ?Is it already ideal shape, length and width or sailors may wish for some improvements ?

There are probably quite a few individual improvements...

It is about as long as it can be, as it is situated between some hills.... however it isn't long enough -> you can see in the videos that the sailors arn't up to top speed when they enter the first gate, and you can see them start to slow down before the end-gate.

It could do with a chop-killer of some sort.


But of course the cost of implementing the improvements.... eek.

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mathew said..
It could do with a chop-killer of some sort.


But of course the cost of implementing the improvements.... eek.

How sailors manage their spin outs in Luderitz ? Or it never happen on the Luderitz channel.. They don't seems to have much room and time to go sideways and landing on the sand at this speed could be painful.
You see, in my proposal where two soft, floating sausages create channel on the water:
- you could regulate the width of the channel on demand
- in the case of uncontrollable spin out your board possibly hit soft barrier and you catapult over to over side and land in the water hopefully

A flexible tube was used to create smooth water for speed runs on Hatteras island North Carolina many years ago. They filled it using an outboard motor and then anchored it in shallow sound water. I only saw pictures, but I think that it worked. A search may turn up some specifics on how they did it.

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Macroscien said..

mathew said..
It could do with a chop-killer of some sort.


But of course the cost of implementing the improvements.... eek.

How sailors manage their spin outs in Luderitz ? Or it never happen on the Luderitz channel.. They don't seems to have much room and time to go sideways and landing on the sand at this speed could be painful.
You see, in my proposal where two soft, floating sausages create channel on the water:
- you could regulate the width of the channel on demand
- in the case of uncontrollable spin out your board possibly hit soft barrier and you catapult over to over side and land in the water hopefully

I recon if you had a spin-out on those boards at those speeds it would only last 1 fifth of a second before the rail caught and you got catapulted, still that may be preferable that hitting the mud wall at 45 knots sideways and feet in the straps. I guess spin out is rarer cause your so broad the Kite-crashes must be totally insane, I've seen a local guy here in the GC have a crash on his race board at 38 knots and he basically got flipped 5 times like a rag doll (big 110KG unit too) ..sorry Im a bit off topic

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tilldark said..

Macroscien said..

mathew said..
It could do with a chop-killer of some sort.


But of course the cost of implementing the improvements.... eek.

How sailors manage their spin outs in Luderitz ? Or it never happen on the Luderitz channel.. They don't seems to have much room and time to go sideways and landing on the sand at this speed could be painful.
You see, in my proposal where two soft, floating sausages create channel on the water:
- you could regulate the width of the channel on demand
- in the case of uncontrollable spin out your board possibly hit soft barrier and you catapult over to over side and land in the water hopefully

I recon if you had a spin-out on those boards at those speeds it would only last 1 fifth of a second before the rail caught and you got catapulted, still that may be preferable that hitting the mud wall at 45 knots sideways and feet in the straps. I guess spin out is rarer cause your so broad the Kite-crashes must be totally insane, I've seen a local guy here in the GC have a crash on his race board at 38 knots and he basically got flipped 5 times like a rag doll (big 110KG unit too) ..sorry Im a bit off topic

That possibly why the best sponsor to Speed Run could be insurance company. Any potential sailor/ rider needs to fill in waiving any claims to the organizer form and purchase life /disability insurance on spot . Regardless how well speed run is organized there is always potential for some harm at those speeds.Possibly the form could be just copied from Drag Racing Tracks or Salt Lake speed seekers....

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choco said..
More effort should be put in to developing ultra efficient sails fins and boards where speeds of 50+ knots can be done in 20-25 knots of wind

With the current windsurfing concept, we are very close to the efficiency limits. The main improvement has come from just sailing in stronger wind in better physical conditions. The increments of improvements are getting smaller all the time. I confidently predict that we will never see a windsurfer of the current configuration go over 50 knots in 25 knots of wind.

I don't think it is impossible that someone will get to 50 knots in 30 knots of wind. We have seen it got close to at Lake George and that is one place it might be possible.

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Macroscien said..
How long is Luderitz channel and what is average width and depth ?Is it already ideal shape, length and width or sailors may wish for some improvements ?

You can see it and measure it on Google earth. From memory it's a bit over 1km

Actually, it is plenty long enough. There is more than enough room to get to top speed and hold it for 10 seconds and then have room to slow down.

Of course. A longer run gives you more chance of getting a better top speed section in variable wind.

the main limitations with the Luderitz canal:

-Very difficult to start due the wind shadow from nearby hill. Super gusty start area.This somewhat limits the boards that can be ridden.

-Very narrow so very unforgiving if you spin out or crash.

-It is straight through the main part. Therefore the ideal wind must be from a very precise direction. Too tight and it is not fast enough. A few degrees too broad and it is death chop rolling waves. Apart from building a 2KM+ canal that gradually bends through about 20 degrees, chop killer artificial weed would help a bit.

-The water level has been too low the last two years. All the records were broken when the canal water level was up to the desert floor ground level so the wind flow was much more laminar right to the water level.

-The wind there comes over a lot of low hills until it gets quite close to the canal. It is very gusty.

-The dirt removed from the canal was piled up too high and close the the lee side. It was improved this year but was not there when the records were broken in 2012.

-It's not in out backyard!


The main advantage is that despite all that, it is the fastest bit of water for kitesurfing and windsurfing that is regularly, reliably accessible so far.

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Macroscien said..
How sailors manage their spin outs in Luderitz ? Or it never happen on the Luderitz channel.. They don't seems to have much room and time to go sideways and landing on the sand at this speed could be painful.
You see, in my proposal where two soft, floating sausages create channel on the water:
- you could regulate the width of the channel on demand
- in the case of uncontrollable spin out your board possibly hit soft barrier and you catapult over to over side and land in the water hopefully

There were a few spin outs, but not many. Some were those brief ones where you lose flow for a fraction of a second and manage to regain it. The others resulted in a crash. If you were lucky or managed it well you may stay in the canal until you stop without hitting the side. I had one of those and consider myself very lucky!

I like the idea of the 'sausages' as long as they are not floating. Have them sitting on the ground in shallow water and then raise the water level right to the top of your 'canal' a few inches above the surrounding water to break the chop. You could regulate the width, but more importantly, the orientation to the ideal angle off the wind - are even make it curved. But probably, there are few materials that are 'soft' when you hit them at 100kph.

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hardie said..

I'll have to take u there one day Daffi, its a huge area, and there are many Venturi funnels. The Locals say South Passage between Dirk Hartog Is and the peninsuala has the strongest wind as the local venturi effect squashes the wind and they say the wind is 10 to 20 kts stronger than Denham, claiming 40 to 50 kts is not uncommon.

That is right near the top of my list of things to do Hardie!

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sailquik said...

choco said..
More effort should be put in to developing ultra efficient sails fins and boards where speeds of 50+ knots can be done in 20-25 knots of wind

With the current windsurfing concept, we are very close to the efficiency limits. The main improvement has come from just sailing in stronger wind in better physical conditions. The increments of improvements are getting smaller all the time. I confidently predict that we will never see a windsurfer of the current configuration go over 50 knots in 25 knots of wind.

I don't think it is impossible that someone will get to 50 knots in 30 knots of wind. We have seen it got close to at Lake George and that is one place it might be possible.

Just need to use a bigger sail like a 7.0m

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choco said..

sailquik said...

choco said..
More effort should be put in to developing ultra efficient sails fins and boards where speeds of 50+ knots can be done in 20-25 knots of wind

With the current windsurfing concept, we are very close to the efficiency limits. The main improvement has come from just sailing in stronger wind in better physical conditions. The increments of improvements are getting smaller all the time. I confidently predict that we will never see a windsurfer of the current configuration go over 50 knots in 25 knots of wind.

I don't think it is impossible that someone will get to 50 knots in 30 knots of wind. We have seen it got close to at Lake George and that is one place it might be possible.

Just need to use a bigger sail like a 7.0m

Speed racing down the channel seems to be one way only. Why the sail then off the shelf standard stock if all speed boats are build asymmetrical ?
Fins becomes already asymmetrical but boards and rigs not yet.
I wish to see soon one way only boards - asymmetrical optimized to provide maximum performance for sailor standing on on side only,
Half boom _ or no boom at all ? Imagine sail batten inside sail - at boom hight reinforced - so could take over the role of the boom. Harness lines attached to it directly and sailor control only by this lines. Works only for speed track sailing.
Or just sail construct as rigid asymmetrical wing, taken straight of any modern glider.

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sailquik said..

Macroscien said..
How long is Luderitz channel and what is average width and depth ?Is it already ideal shape, length and width or sailors may wish for some improvements ?

From my investigations looks that Luderitz channel is about 800 meters long and 30 meters wide ( ?) at angle to the wind 140 degree.
I still don't know what is the depth in the middle of that channel.
If 40 cm as absolute minimum will be enough or we need deeper artificial channel ? Assuming that water in our channel is managed to dump also all waves created inside so surface remains almost glass like.

If water density may any influence on the resistance ? We know that salt water is much more dense that fresh water. If that cause higher resistance to the fin ? Bounce doesn't really interest us at all as high speed board is skimping on the surface only.

Not sure if any surfactant lowering surface tension my have any effect on our boar performance - or say skimping over 0.5 cm of the slicky oil ( organic natural of course may help).

This is another purpose build channel by French specifically for windsurfers :


en.wikipedia.org/wiki/The_Canal

This picture give us good idea where descent quality wind is in Australia.
Maybe more refined search could be even better as we are interested in winds above 20 knots ( not just 10-15 but constant)


Looks like Tasmania wins hands down in this wind competition but Perth and Adelaide regions looks also promising.

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Macroscien said.

Speed racing down the channel seems to be one way only. Why the sail then off the shelf standard stock if all speed boats are build asymmetrical ?
Fins becomes already asymmetrical but boards and rigs not yet.
I wish to see soon one way only boards - asymmetrical optimized to provide maximum performance for sailor standing on on side only,
Half boom _ or no boom at all ? Imagine sail batten inside sail - at boom hight reinforced - so could take over the role of the boom. Harness lines attached to it directly and sailor control only by this lines. Works only for speed track sailing.
Or just sail construct as rigid asymmetrical wing, taken straight of any modern glider.

You need to look closer at some of the pics...
- the boards dont have a leaward footstrap
- the booms are one-sided
- the fins are assymetrical
- most speed sails have their battens all on one-side (starboard tack)

That said, in most cases, the whole "one way setup" has shown to be not worth it.... eg: there is evidence to suggest that having the sail physically touching the boom, gives a better result than allowing the sail to free-set.

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Macroscien said..

From my investigations looks that Luderitz channel is about 800 meters long and 30 meters wide ( ?) at angle to the wind 140 degree.
I still don't know what is the depth in the middle of that channel.
If 40 cm as absolute minimum will be enough or we need deeper artificial channel ? Assuming that water in our channel is managed to dump also all waves created inside so surface remains almost glass like.

If water density may any influence on the resistance ? We know that salt water is much more dense that fresh water. If that cause higher resistance to the fin ? Bounce doesn't really interest us at all as high speed board is skimping on the surface only.

Not sure if any surfactant lowering surface tension my have any effect on our boar performance - or say skimping over 0.5 cm of the slicky oil ( organic natural of course may help).

This is another purpose build channel by French specifically for windsurfers :


en.wikipedia.org/wiki/The_Canal

Correction on some points:

- you do know that sailquick has actually sailed Luderitz ... so if you correct him on technicalities, you had better be accurate ! Pretty sure it isn't 30m wide... the mast is 4m tall, so that help put the width into perspective:

- if you can control the depth with any accuracy, then 20cm is the max... that would give 2-3cm of depth below the fin!

- that "French canal" pic is ... luderitz-speed.com/event-news/luderitz-speed-challenge-2011

While my last two posts to Macro, were mostly tongue-in-cheek corrections, there may be some merit in attempting an artificial speed course, using a tech such as this: www.kickstarter.com/projects/airwavesurfreefs/surfing-airwave-inflatable-eco-friendly-surf-reef

Macro is correct. About 800m long but very narrow. I think they call it 6m wide but not sure. It is not quite as wide as it looks because you lose a bit on each side to a shallow washed area at half to 1m wide. The depth was supposed to be over 50cm all the way to satisfy WSSRC rules on minimum depth. There were definitely shallower bits! Ask Jacques!
The wind angle varies a bit on different days and changed during the day on some days. Talking a range of around 15 degrees or slightly more. One drawback of a straight canal like Luderitz is that individual sailors can't experiment with different wind angles. You got what you got.
The wind map above is interesting for general windsurfing but does not tell the whole story for specialized speed sailing. For that you need a place that has regular winds from a certain predictable direction that exceed 30-35 knots, preferably stronger. The best spots that are sailed regularly in Vic and Tas still only meet these ideal conditions a few times a year. There still may be places that meet the criteria more often like Shark Bay if the right course could be constructed. Eg: The Henty river probably has the right wind conditions quite often but the course changes seasonally and is only right infrequently.

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mathew said..
While my last two posts to Macro, were mostly tongue-in-cheek corrections, there may be some merit in attempting an artificial speed course, using a tech such as this: www.kickstarter.com/projects/airwavesurfreefs/surfing-airwave-inflatable-eco-friendly-surf-reef

I thought the whole topic had gone that way. Extending Macro's water management ideas, I recall my days as a youngster in those circular above ground swimming pools. It's not hard for a few wading kids to generate a vortex around a vertical axis involving several tonnes of water. If the channel was built with a semi-circular, or even 3/4 circular cross section, then it wouldn't take too much electrical paddle power to generate a long vortex on a horizontal axis.

This would sweep any wind-generated waves below the surface, sucked under the windward bank, where they should (could?) be dissipated.

But there's more! If the vortex imparted 5 to 10 knots of surface current into the windward bank.. Well that's 5 to 10 knots of apparent wind vector-added to whatever is naturally blowing over the trench! And it's a gustless 5 to 10 knots!

Whether, not or how this surface current in the trench should be subtracted from the GPS recorded speed is another issue.

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Ian K said..

mathew said..
While my last two posts to Macro, were mostly tongue-in-cheek corrections, there may be some merit in attempting an artificial speed course, using a tech such as this: www.kickstarter.com/projects/airwavesurfreefs/surfing-airwave-inflatable-eco-friendly-surf-reef

I thought the whole topic had gone that way. Extending Macro's water management ideas, I recall my days as a youngster in those circular above ground swimming pools. It's not hard for a few wading kids to generate a vortex around a vertical axis involving several tonnes of water. If the channel was built with a semi-circular, or even 3/4 circular cross section, then it wouldn't take too much electrical paddle power to generate a long vortex on a horizontal axis.

This would sweep any wind-generated waves below the surface, sucked under the windward bank, where they should (could?) be dissipated.

But there's more! If the vortex imparted 5 to 10 knots of surface current into the windward bank.. Well that's 5 to 10 knots of apparent wind vector-added to whatever is naturally blowing over the trench! And it's a gustless 5 to 10 knots!

Whether, not or how this surface current in the trench should be subtracted from the GPS recorded speed is another issue.

You know, that is ingenious idea. If instead of 30 meters wide channel we could create rather circular 1 km bowl , gut with glassy water, we could resolve few problems:

-wind direction : every wind direction is good
-sailor preference and the best angle to the wind- other competition like alpha hour-sailor preference -some are better on left or right tack - but on thin channel is no choice.

Such artificial circular pool, at 40 cm depth and 1 km diameter need definitely active wave dampening system. What I could foresee could be: -sort of natural or artificial weeds covering bottom-vortex ? idea needs to be tested on bigger then kids swimming pool. I thing vortex will create waves on its own.-high tech engineering : wave like shape of the bottom to create waves in different phases to annihilate each other.-active board shaping to create waves in opposite phase
-partly pneumatic bottom sections to dump wave energy
-water surface treatment with surfactant or oil or (filling whole bowl with different liquid altogether : whiskey or beer ? ) -freezing the lake ? But to create 1 km diameter pool we need investor that come with at leats 256 acres of land ( and surrendering land dead flat too) .
Unleas there is additional mainstream usage for the pool , cost will be prohibitive to build such bowl. But if main investor use the bowl to produce something and windsurfing is just add on there is still possible.

Possible usage for 1 km lake:
-fisheries-small algae growing or plankton
-salt water evaporation
- and salt mining/ retrieving from ocean
-water cooling for nuclear or coal plant
-waste water deposit from mines
-waster water treatment plant-radio telescope (?)
-storm/ rain / irrigation water tank
-desalination plant using sun energy for filtration instead of electric pump (sci-fi)



But instead of creating whole circle 1 km in diameter we could create elliptical shape channel 30 meters wide !
Simply two Luderitz channels mirrored and joined together. We could sail in both directions, do alpha and hour !If we do 2 km long diameter then we could exercise NM competition too .


Needs to be tested if now creating water flow / current could swap away waves by centrifugal forces on elliptical channel.

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Ian K said..

mathew said..
While my last two posts to Macro, were mostly tongue-in-cheek corrections, there may be some merit in attempting an artificial speed course, using a tech such as this: www.kickstarter.com/projects/airwavesurfreefs/surfing-airwave-inflatable-eco-friendly-surf-reef

I thought the whole topic had gone that way. Extending Macro's water management ideas, I recall my days as a youngster in those circular above ground swimming pools. It's not hard for a few wading kids to generate a vortex around a vertical axis involving several tonnes of water. If the channel was built with a semi-circular, or even 3/4 circular cross section, then it wouldn't take too much electrical paddle power to generate a long vortex on a horizontal axis.

This would sweep any wind-generated waves below the surface, sucked under the windward bank, where they should (could?) be dissipated.

But there's more! If the vortex imparted 5 to 10 knots of surface current into the windward bank.. Well that's 5 to 10 knots of apparent wind vector-added to whatever is naturally blowing over the trench! And it's a gustless 5 to 10 knots!

Whether, not or how this surface current in the trench should be subtracted from the GPS recorded speed is another issue.

BTW. Do you realize then if we create vortex on 1 km diameter lake then centrifugal forces will rise the water level at the edges possibly several meters and surface surfers could spend whole day surfing down the slop ?

This is definitely getting weird!

Interesting though......

I've only had a skim through the thread so sorry if a similar idea was put up already. Just thought id chuck in some ideas that have come up in our team in the past. Our local speed strip is Primbee NSW. We are lucky to have a shallow stretch of water that runs for a mile or so along the eastern shore of Lake Illawarra. Most years we get good banks of weed to knock the chop off, giving nice smooth section for speed runs. Unfortunately last winter the weed didn't really appear so some of us started talking about artificial weed bank ideas. Keep it simple, DIY type stuff. As its not deep the ideas were along the lines of pool lane style rope that would float on the surface, to artificial weed bank type of things that could consist of attaching small floats (sections of pool noodle?) to a chain that would sit on or anchor to the bottom and float up to the surface to imitate weed. You could even sail over it if you had to. It would be something that could be dragged out and put in place when needed, maybe in sections. Anyway was just talk and probably needs more beer and chat to really figure out the complex design details

I'd guess seaweed is much better at dissipating chop if it's attached to the bottom, dragging on the waves rather than going with the flow. Pool lane ropes may not be anywhere near as effective.

Artificial seaweed has been tried but it all soon got pulled out or shredded by wave action. You can't beat the natural product!


http://www.snh.org.uk/publications/on-line/heritagemanagement/erosion/appendix_1.17.shtml

Yeah Ian I think the seaweed idea would work best. Personally I don't think anything long term is a good idea as its bound to come apart at some point and make a mess of the place. If something could be created that was effective, simple to construct and easy to set up and pack up we'd be laughing. Oh and a 40knt westerly every 2 or 3 days. Not asking much I think.

What about an Olympic class rowing course. I don't know much about them but I think they are at least 2000m. We have one here in WA at Champion Lakes and I have often wondered about the depth of water, any wave reduction properties, orientation to prevailing winds and removability of the lane markers.

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TerryF said..
What about an Olympic class rowing course. I don't know much about them but I think they are at least 2000m. We have one here in WA at Champion Lakes and I have often wondered about the depth of water, any wave reduction properties, orientation to prevailing winds and removability of the lane markers.

Terry, I measured the length of the lake & you could just manage a NM.
Apparently they won't let us use it though & the lane markers would be a bugger
It would work well in an Easterly i reckon.

I was certainly thinking that this morning when the easterly blew