so one piece of software uploaded data and i have saved it. i then tried to open it in the G7towin program but it didn't make any sense!!
hopefully I can find a users guide.
Download you're data via G7toWin, save file somewhere handy (.gpx). Open GPSAR and then open file with that, then you'll have lots of pretty tracks on you're screen to play with.
Crash try this....using G7towin
open the GPS tab....
open the download from GPS option
click on tracks...
If you get a GPS not found message check your conection.This has been the cause of most problems. Push it hard in.
When its finished save the track(dd mm yy.gpx) into a folder of your choosing
I tend to use Mal,s program Realspeed as you don,t have to manually check for spikes.
To use this or gpsaction replay open the file tab and click on open and direct it to your folder.
Hope this helps
Here's a technical question for you. Using a TB62, 32cm Fin and V8 6.5m sail I am getting 30 to 32 knt runs, typically in 20 - 25 knt winds flatish water.
When I get a big gust I'm thinking that I should pick up my speed, however I tend to hit the limit where more power in the sail doesn't give me more speed. My suspision is that my stance changes as I tense up to handle the power. I may be over sheeting ?? not sure. Just feels that I'm working harder without benefit. Any tips?
I'm not a total expert, but oversheeting is no good for speed. You want to bear off with the gust, and hang as much leverage on the sail as you can with maximum power in the sail. So set up is critical that you have set up mast foot position and have boom height and harness lines in good positions for those broad reach runs. Then technique comes into it, coz u gotta have leverage to direct power through the board, so stance, weight distribution and leverage come into it. Keep experimenting till you sart hitting 33's and 34's in same conditions. If however, you already have set up and technique dialled, then you may be maxing out in what is possible for your equipment and water conditions. However, over-sheeting does not sound good!!
Waiting4Wind:
Sheet out slightly?
In "Faster" they talk about sheeting out when a gust hits, not to spill power, but because the angle of the apparent wind changes to be more from the beam and less from the nose. So you sheet out to keep the sail at the correct angle to the wind -- which makes you go faster.
That's the theory, anyway!
Here is a real good explanation by Finian of how to go about ithttp://www.boardseekermag.com/technique/index_021.htm
Click on lets talk speed link
or here is the direct link which you will have to cut and paste direct into your media player URL (you can save from there)
www.boardseekermag.com/moves_and_movies/speed/TECH_021_FINIAN_SPEED512K_Stream.wmv
Ok that makes sense I think. I've been doing the opposite locking the sail in tighter in reaction to the gust...working on the old principle of not backing off. I remember several times chopping my back foot toes with the foot of the sail as I locked it into the deck.
I think i have done the slight sheet out inadvertently at times and noticed a pick up in speed but wasn't quite sure what I was doing with my stance to recreate that moment the time around. As soon as we get some wind I'll be out there to test the theory. Thanks for the tips
quote:
Originally posted by hardie
OK, this thread is for speed advice.
The speed guru is not me, but the community of seabreeze windsurfers around Australia. So put your speed questions here, and anyone that feels they can help, can answer!!!
I'll just start off with something on sails, that people have reacted to, questions such as how do you rig a sail to go fast, this is what I put on another thread:
news for you he switch to maui sails
Wanna know what a fast sail looks like, check Martin Van der Meurs, rig when he did 49.4 knots, bottom full, top flat to inverted, almost like an s shape:http://www.naishsails.com/news/news_030107.php
That is from the naish website, so they hold 2 world records.
All the Australian records are held by KA Koncepts, so maybe some of the KA people can talk about their sails.
Neil Pryde have their RS series.
And other brands have theirs, so please all feel free to contirbute.
how did you guys rig older sails (pre twisting) still downhall ****loads or just take out horizontal creases
Define old.
Race sail wise most sails post 92 were extreme loose leach- downhaul until the leach was loose similar to sails now. Around 94 pryde began using hollow leach to induce (static) twist, this was continued with VX which did not require the leach looseness of earlier models, gaastra and north at the same time reduced the amount of looseness required with progressive twist.
All evolved into more dynamic twist- more or less this continued up to 2000 (the s*** tip revoluition), off the wind however the pro's still piled on the downhaul with anything from tape to stickers and hacksaw blades being stuck on the leach to stop the sail shaking apart on the upwind leg.
Prior to 92 are we talking cammed or not? Since most sails weren't cammed follow the rules for rigging raf sails. Cammed you are own you're own, most those that I tried were dogs which i'd rather forget... with one or two exceptions.
Sails have evolved pretty dramatically, i was bewildered very early in my sailboarding life that the wind would suddenly try to slam me down from opposite sides of the sail, that was with brand new sails for the time ('94 aerotech ultimate). Now you can probably go twice as fast on wavesails and you still wont get backwinded.
yeah cant no matter what i try get sails to rig with floppy leach. have 5.8 and 4.6 tiga slalom world cup. felt really quick on sunday at elwood went out after sailing (skiffs) was blowing 24ish knots, only had 5.8 so went out with that (im 60 kgs) and was way overpowered but felt quite controlled. pulled downhall on really tight and outhall really tight. with new mast (new 15 year old mast..) sail seemed to rig better, when downhauled to batten went flat which was good but sail still wouldnt twist off... what did you guys used to do back in the day??
got a waterstart wooohooo... no more uphauling...
My recollection of race sails from 1987 to 1993 was that they did not have loose leaches at all. I think a Tiga Slalom World Cup sail was similar to the NP World Cup Racing series and would have been tight leached.
Dont try to downhaul a tight leached sail to get a loose leach, it will not happen, you will break the mast or sail before you get anything resembling a modern setup.
Tight leaches made for very powerful sails, but smaller windrange.
JB
Can someone explain the differences and advantages of symmetrical versus asymmetrical fins for speed please?
Yeah, symmetrical fins are the same on both sides and asymmetrical aren't
oh, you meant a serious explanation
quote:
Originally posted by grumplestiltskin
Yeah, symmetrical fins are the same on both sides and asymmetrical aren't
oh, you meant a serious explanation
when are you gonna grow up grumps ffsake
Anyone know how fast a Kinetic Centurion 110ltr, 247 by 77 would be? i know you can't tell me exactly, but would it be quick?!? Is it any good as I'm thinking of buying one for lighter wind windsurfing.
Cheers
quote:
Originally posted by Crash Landing
Anyone know how fast a Kinetic Centurion 110ltr, 247 by 77 would be? i know you can't tell me exactly, but would it be quick?!? Is it any good as I'm thinking of buying one for lighter wind windsurfing.
Cheers
Fair enough, it's for 6.8m - 8.7m weather...
I just need a faster board for those flat days and I don't want to spend a lot of money!
quote:
Originally posted by Crash Landing
Fair enough, it's for 6.8m - 8.7m weather...
I just need a faster board for those flat days and I don't want to spend a lot of money!
Hi Hardie this is copied off Mals site and gives a far better explation than I could give
An asymmetric fin allows the same size fin to produce more lift for roughly the same amount of drag. This directly improves the lift-to-drag ratio, making a more effective fin. See the following graphs which show a comparison between a symmetric slalom foil in black, and the same foil in red with a coefficient of lift of 0.2, making it an asymmetric.
Lift to drag comparison between two sections. The black line shows the lift-to-drag of a symmetric section. The red line shows the same foil applied to a cambered centerline, making an asymmetric section.
Lift to drag relative to angle of attack. Notice how the asymmetric section makes lift even at 0 and negative angles of attack. So typically an asymmetric fin will not crab the board sideways as much as a symmetric section.
There,s more info at www dot intellimass dot com
Good wide boards will easily do 30+ knots. Formula have done over 30 knots so no excuses really.
quote:
Originally posted by kato
Hi Hardie this is copied off Mals site and gives a far better explation than I could give
An asymmetric fin allows the same size fin to produce more lift for roughly the same amount of drag. This directly improves the lift-to-drag ratio, making a more effective fin. See the following graphs which show a comparison between a symmetric slalom foil in black, and the same foil in red with a coefficient of lift of 0.2, making it an asymmetric.
Lift to drag comparison between two sections. The black line shows the lift-to-drag of a symmetric section. The red line shows the same foil applied to a cambered centerline, making an asymmetric section.
Lift to drag relative to angle of attack. Notice how the asymmetric section makes lift even at 0 and negative angles of attack. So typically an asymmetric fin will not crab the board sideways as much as a symmetric section.
There,s more info at www dot intellimass dot com
seriously this time
Doesn't the assymetrical in this case apply the to the foil shape compared to the outside plan shape? i.e. the foiling is different between the top and the bottom etc.
Hi Hardie,yes upwind performance can suffer with some fins,but the downwind makes up for it and more.Assy fins don,t spin out unless you do something stupid with them like I did last week.You can also push really hard on them and get a lot of the board out of the water.BUT you can also do so really good times on symm fins.Find out what you like and go fast.
Assy fins have a different foil shape on each side. ie the wide point on the fin may be at a different point.One side the wide point might be at 37% on the other at49%. Hard to explain without drawing it.Read the posts under fins it might explain it better.30/40wsw at the pit tommorrow might see if the theories work
After seeing Vando sail one of Mal's assymetric fins at "the pit" where he ran down wind with great control and then pointed back up the course (higher than I could point with a symmetric fin) - the performance issues when pointing 'close to the wind' may not be as great as some think.
Will leave it to Vando to comment further.
- J
Yep Those fins of Mals really do work in both directions.
Of coast your not going to go as fast on port tack but you can still push them up wind. Unfortunately up here in QLD all the fastest spots are port tack bummer
.
The TM45's certainly did the business at Sandy Point, how's Mal Wright's average of 45.5 knots, if nothing lease thats proof they work!!!!! Might have to get one.
Given they are optimised for 40 to 45 knots of board speed, how do they go in less ideal situations. Say the wind is between 20 and 25, which is the usual summer breeze here, will they work efficiently in those winds, or are you better off with a bigger fin?
