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Speed Sailing

> 10 years ago
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General Gps & Speed Waves Foiling Gear Reviews Lost & Found WA NSW QLD SA VIC TAS
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DavMen
DavMen
NSW
1510 posts
DavMen DavMen
NSW, 1510 posts
15 Jun 2006 6:34am
Intersting segment on speed sailing on Beyond 2000 last night(14/6/2006).

Have a look at these sites.

www.beyond.com.au

http://myweb.tiscali.co.uk/6031769/sailrocket/

DavMen

nebbian
nebbian
WA
6277 posts
nebbian nebbian
WA, 6277 posts
15 Jun 2006 1:18pm
What a crazy design!

Still, 22 square metres of sail is going to have a fair bit of pull...
Was interested to note that the sail-driven water speed record is currently held by Finian Maynard on a windsurfer.

Any physics majors want to discuss the design? It all looks a little bit flimsy to me, wouldn't want to crash out at 50 knots
But it looks like they've had a test run or two on it, would be interested to see what sort of speeds they got. Does anyone know?
mkseven
mkseven
QLD
2315 posts
mkseven mkseven
QLD, 2315 posts
15 Jun 2006 6:29pm
quote:
Originally posted by nebbian

What a crazy design!


Exactly, if all these eccentrics spent that money on developing sailboards 50knots would have been broken. That said I think Macquarie Innovations will take it- too much tried and proven development there, and their first runs were good.
mathew
mathew
QLD
2172 posts
mathew mathew
QLD, 2172 posts
16 Jun 2006 7:40am
The biggest problem that I can see with the design is that the windward pod is meant to touch the water - or at least the rudder is meant to touch.

After seeing how MI lifts out of the water, and how little surface area that speedboards have in contact with the water -> I just dont see this thing will get past about 45 knots, as there appears to be too many areas of the design where drag will affect the speed.

But what would I know...
ka43
ka43
NSW
3105 posts
ka43 ka43
NSW, 3105 posts
16 Jun 2006 7:55am
After watching that bit on the program I think they have as much chance of those canetoads winning the decider in Mexico.
It was pushing water and did not look very efficient, think they were maxing at well under 30. Had so much hull in the water and did not look like planing up was going to be any easier.
Still at least they are having a go.
jsn_batman
jsn_batman
WA
86 posts
jsn_batman jsn_batman
WA, 86 posts
16 Jun 2006 6:04am
the way it designed could have been a little different it still has a lot of surface area on the water, i mean compare to the sail and wind strength, for speed sailing in 15 knots i use a fully cambered 7.5m2 sail, in 15 knots they are using a 22m2 sail, big difference. but the surface area on the windsurfing board (at full planing speed say 70km p/h) is sumwhat less then the 'yatch'. so somehow if you could take some of the inefficincy out of the sail of our windsurfing gear we would be right.
mkseven
mkseven
QLD
2315 posts
mkseven mkseven
QLD, 2315 posts
16 Jun 2006 8:11am
quote:
Originally posted by ka43

After watching that bit on the program I think they have as much chance of those canetoads winning the decider in Mexico.
It was pushing water and did not look very efficient, think they were maxing at well under 30. Had so much hull in the water and did not look like planing up was going to be any easier.
Still at least they are having a go.


I'm in agreeance with you, to me it is all about reducing the drag/contact of the water- look at the speeds (ice) speedsailors effortlessly get to. Alot of their speeds are achieved with "low tech" 1 or 2 cam sails also.

How many boat/contraptions have passed 44knots? I dont think there have been that many, to get near 50 they should be passing 40 easily in good conditions. Maybe MI should go to Weymouth and show them how it's done.

Does everyone in this country watch bloody football?
mkseven
mkseven
QLD
2315 posts
mkseven mkseven
QLD, 2315 posts
16 Jun 2006 8:22am
quote:
Originally posted by jsn_batman

the way it designed could have been a little different it still has a lot of surface area on the water, i mean compare to the sail and wind strength, for speed sailing in 15 knots i use a fully cambered 7.5m2 sail, in 15 knots they are using a 22m2 sail, big difference. but the surface area on the windsurfing board (at full planing speed say 70km p/h) is sumwhat less then the 'yatch'. so somehow if you could take some of the inefficincy out of the sail of our windsurfing gear we would be right.


The sails arent inefficient, maybe more that they arent perfectly suited to what we are trying to do. Trying to reduce wetted area whilst the rig is forcing the board into the water is an example of this.

With the money some of these contraption owners are throwing at this we could have solved many myths and flow tested designs- we would know whether cavitation at 50 knots is an issue. Then it is a matter of just getting the right rider. The boats should be kicking our ass, windsurfers have a huge amount of human factor (too much).
jsn_batman
jsn_batman
WA
86 posts
jsn_batman jsn_batman
WA, 86 posts
16 Jun 2006 6:41am
have to agree with you there mkseven, trying to get 'rid of' human error or aerodynamic issues woulod be quite hard. so in 'theory' then kitesurfing should be quicker if you sould control the kite board at those speeds?
mkseven
mkseven
QLD
2315 posts
mkseven mkseven
QLD, 2315 posts
16 Jun 2006 9:02am
Should be and maybe will be with some further kite and board development, they have further benefits of being able to kite in the flatest water and displacing less. I dont think it falls into the category of sail powered craft though.
jsn_batman
jsn_batman
WA
86 posts
jsn_batman jsn_batman
WA, 86 posts
16 Jun 2006 7:15am
thats true, i think windsurfing has progressed to a point where we are only perfecting what we have instead of something radical. maybe thats what we need a radical change in board design only problem is when science/theory meets real life there are so many more variables to take in that it doesnt work. maybe we might see some change in the future in speed sailing. well one day is all i can say, i dont shape boards or have an input to sail designs, so maybe thats we its at, we had the same with surfing it could only progress so far till surfboards could only be perfected not redesigned.
mkseven
mkseven
QLD
2315 posts
mkseven mkseven
QLD, 2315 posts
16 Jun 2006 9:33am
Things have developed alot recently, technology is removing the human factor. CAD/CAM shaped and produced boards, bottom shapes which would have been pretty hard to replicate in the past (ie hypersonic) and higher accuracy. Boards are benefiting from different bottom shapes; cutouts, falcons have monoconcaves and the like- for a good 10 years if you wanted to go fast there was only 1 shape, dead flat washing out into slight V. I think we will see some benefits coming out of GPS testing, no more should we have gear that isnt as fast or have the same range as previous years.
Gestalt
Gestalt
QLD
14965 posts
Gestalt Gestalt
QLD, 14965 posts
16 Jun 2006 10:19am
i believe board and fin drag is the big issue.

boards can and have been designed that are very fast with small wetted surface area and drag but they are very hard to control.

an eg would be a board with a deep concave producing tiny flats on either side... in theory very fast with almost no water surface drag but almost impossible to sail and imposible to turn.

it seems to me that the tweaking of board design is more about improving control allowing the sailor to handle the higher speeds.
maybe a short hydrofoil type shape that can be controlled.

the cutouts that most board makers are adopting significantly reduce the drag at the tail of the board. when used with wider tail boards it is a great outcome allowing better fin control while still keeping the wetted surface drag to a min.

fin design is where i see the next big step forward. not sure how but maybe a change in material or shape.
nebbian
nebbian
WA
6277 posts
nebbian nebbian
WA, 6277 posts
16 Jun 2006 8:37am
Did anyone else notice the shape of the 'supercavitating' fin they're using? Yowzers! I'm sure they've done their homework but with such a blunt trailing edge you'd expect a fair bit of drag, wouldn't you?

It's almost as if they're trying for supersonic speeds (faster than the speed of sound in water, which is a heck of a lot faster than the speed of sound in air, so in other words faster than 1000 km/h). Or maybe cavitation behaves something like going supersonic? I know that supersonic wings on jets look very weird.

mathew: At least their sail is angled so it produces some vertical lift as well as well as forward drive, reducing the weight that the planing surface has to lift.
I reckon that their design is more like a kitesurfer than a windsurfer, sail downwind supporting itself, weight over the planing surface, lots of sideways pull on the 'hull'.
jsn_batman
jsn_batman
WA
86 posts
jsn_batman jsn_batman
WA, 86 posts
16 Jun 2006 8:51am
well when you start thinking of cavitation it creates a vacuum behing the fin and there is no drag in a vacuum because there is nothing its just like space. So i guess that would work for that individual craft but not for windsurfing where back foot pressure is in play.
mkseven
mkseven
QLD
2315 posts
mkseven mkseven
QLD, 2315 posts
16 Jun 2006 11:46am
Nebbian, any links on this fin- in general cavitation is bad. I think boogie is on the money with his X speed fins.
yoyo
yoyo
WA
1646 posts
yoyo yoyo
WA, 1646 posts
16 Jun 2006 11:18am
Not the first gen, they seem slower than other speed fins.. nicely finished tho but too flexy .. possibly later versions are stiffer/better/faster.. Still many different ways to skin a cat
nebbian
nebbian
WA
6277 posts
nebbian nebbian
WA, 6277 posts
16 Jun 2006 11:32am
Here's a link to the fin design page:
http://myweb.tiscali.co.uk/6031769/sailrocket/boat-research.htm

jsn_batman:
Vacuum behind the fin, with pressure in front of it, means DRAG, and lots of it. That's pretty much what drag is: low pressure on the trailing edge of the object. There are lots of different ways to get drag, but they all boil down to a lower pressure behind the object. A vacuum is an extreme form of low pressure, and is very bad unless you can get the front of the object to have a vacuum around it as well... in which case you get no lift.

If they could only get up to 30 knots then as KA43 says, they've got a heck of a long way to go. A decent level windsurfer can spend $3000 and go faster than 30 knots, compare this to how much these guys have spent
hardman
hardman
1116 posts
hardman hardman
1116 posts
16 Jun 2006 11:37am
It's all very interesting and some of it even fascinating.

But it brings into emphasis what an amazing sport ours is.

My fastest speed of 34.4 knots was done on a 10 year old wave board, with an old weed fin about same vintage, using a 4 year old ezzy wave sail. all up $600-800.00 worth. For less than a thousand dollars on a windsurfer you can crack 30 knots.
mkseven
mkseven
QLD
2315 posts
mkseven mkseven
QLD, 2315 posts
16 Jun 2006 1:53pm
Very true hardman... btw no offence but how much wind was there

Not many sports keep developing as fast as windsurfing is after 30 years- thats what keeps it fun.

The sailrocket thing is having heaps of university input... they dont stand a chance
jsn_batman
jsn_batman
WA
86 posts
jsn_batman jsn_batman
WA, 86 posts
16 Jun 2006 12:27pm
what a about on off centred mast track and offcenter fin, would that help. well at 50knots you might have to looks at wings in order to control your flight. i mean im not fullon into speed sailing BUT doesn't mean i dont spped sailing, using freeride gear and trying to get the most out of my gear is hard. right. how ever it is comfortable at all speeds. where as speed gear is so comfortable at high speeds its a dream.
mathew
mathew
QLD
2172 posts
mathew mathew
QLD, 2172 posts
16 Jun 2006 3:28pm
quote:
Originally posted by nebbian

Did anyone else notice the shape of the 'supercavitating' fin they're using? Yowzers! I'm sure they've done their homework but with such a blunt trailing edge you'd expect a fair bit of drag, wouldn't you?

It's almost as if they're trying for supersonic speeds (faster than the speed of sound in water, which is a heck of a lot faster than the speed of sound in air, so in other words faster than 1000 km/h). Or maybe cavitation behaves something like going supersonic? I know that supersonic wings on jets look very weird.

mathew: At least their sail is angled so it produces some vertical lift as well as well as forward drive, reducing the weight that the planing surface has to lift.
I reckon that their design is more like a kitesurfer than a windsurfer, sail downwind supporting itself, weight over the planing surface, lots of sideways pull on the 'hull'.


The blunt trailing edge is an interesting one... its like the golf ball idea - is it faster to have a rough surface or not? The answer is as always -> it depends...!

Having the sail produce vertical lift is good in that helps to reduce the wetted surface area - but it also has the effect of reducing control (there is now a lifting force to content with). So it is a trade off.

As for kitesurfing... there has been some discussion around the speedsurfing circles (I'm just starting to get involved in them...). Some windsurfers freely admit that with a bit more technical development (the tech is still quite young) that kites could ends up holding the world record.
mathew
mathew
QLD
2172 posts
mathew mathew
QLD, 2172 posts
16 Jun 2006 3:51pm
quote:
Originally posted by jsn_batman

what a about on off centred mast track and offcenter fin, would that help. well at 50knots you might have to looks at wings in order to control your flight. i mean im not fullon into speed sailing BUT doesn't mean i dont spped sailing, using freeride gear and trying to get the most out of my gear is hard. right. how ever it is comfortable at all speeds. where as speed gear is so comfortable at high speeds its a dream.


Off-center designs (fin, mask track, person) were tried 10 years ago BGPS (before GPS). The performance result was inconslusive, but had a negivate point in that the gear was next to impossible to sail back upwind.

Now its AGPS, the concept is being investigated again. The differnece between then and now is that, now the unusual designs being tested are expecting no more than say 1-5% efficiency increases. But that small increase is heaps when you are travelling at 40 knots plus.
hardman
hardman
1116 posts
hardman hardman
1116 posts
16 Jun 2006 2:20pm
quote:
Originally posted by mkseven

Very true hardman... btw no offence but how much wind was there



25 to 30 knots.
mkseven
mkseven
QLD
2315 posts
mkseven mkseven
QLD, 2315 posts
16 Jun 2006 5:13pm
I thought you were supposed to be heavy, 34 knots on a waveboard I'd need a good 35 knots

You are correct though about the pricing, for $1000 you could have the board and sails which were used to break production speed records 10 or more years ago- f2 sputnik 270 or 265 and a quiver of Mk IV's or slalom pro's and you are laughing.
decrepit
decrepit
WA
12885 posts
decrepit decrepit
WA, 12885 posts
16 Jun 2006 5:32pm
The first thing I see looking at that machine, is a long beam with drive at one end and drag at the other. OK if those forces are in line with the beam, but they're at right angles to it and opposing each other. In my book that's a great recipe for going along in tiny little circles!!!!
To stop the turning moment they'd need huge amounts of rudder, producing even more turning moment and drag. Not surprised it hasn't cracked 30kts, and I guess it only goes fast in one direction, (unless there are 2 of them, one a mirror image of the other) that must limit it's operating conditions somewhat.
mathew
mathew
QLD
2172 posts
mathew mathew
QLD, 2172 posts
16 Jun 2006 9:42pm
quote:
Originally posted by mkseven

I thought you were supposed to be heavy, 34 knots on a waveboard I'd need a good 35 knots

You are correct though about the pricing, for $1000 you could have the board and sails which were used to break production speed records 10 or more years ago- f2 sputnik 270 or 265 and a quiver of Mk IV's or slalom pro's and you are laughing.


agreed - just last year my Bombora X-it died (about 12yrs old), I was doing 30+ knots, this is with 10yr old slalom sails (kind of scary when the board flex's along its length...).

Most people should be able to hit 30kts on just about any gear - even on rough water like Port Phillip Bay.
RAL INN
RAL INN
SA
2898 posts
RAL INN RAL INN
SA, 2898 posts
17 Jun 2006 8:55am
Over 30 kts is relatively easy and fun and feels very fast.

there is a big difference in how fast you feel you are going for about every 2kts you increase this.

So for those looking for fun in speed sailing, just aiming for those extra 2 kts is a worthwhile experience.

over 35kts in less than ideal conditions is worthy of merit and those who have done this probably know they are alive at the end of the run.

over powered 37+kts running off the end of the course into unprotected water. Now thats an adrenalin rush.
kato
kato
VIC
3530 posts
kato kato
VIC, 3530 posts
20 Jun 2006 7:48pm
Interesting discussion.Having seen the show i wouldn,t discount any one putting that much time and effort into going fast.MI at the moment has the points on the board with a proven design but have been frustrated by the wrong winds.One scheduled sail day had 40 to 50kts at the perfect direction,just a bit to much.Great for me though.If getting to 50kts was easy every one would be doing it.One advantage we have is that we can do more runs down the course therefore increasing the chance of that lucky gust.I suspect that the kites might prove to be the fastest given that there is much more developement to be done.Dave T is doing pretty well.Fins with max thickness at 50-60%+ may also hold the answer at those speeds.The GPS revolution has made speed sailing fun again.
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