Hi all wind beggars,
Question 1:
Can anyone tell me, is there roughly relationship between the windsurfing speed we get based on wind speed?
Like use wind speed times 1.5
10 knots ?1.5= 15 knots
Sail is 5 m, times 1
10 m , times 2
15?2= 30 knots
So max speed can get 30 knots.
Other example, like horsepower, sails as bigger, power increase. 10m sail should be two times of 5m sails, so if same skill, same weight of surfer and board, same wind, 10 m sailer should be double speed of 5 m surfer.
I try to figure out efficiency of my skill. Like today, wind was 10 knot, how much speed I should get?
Today I could feel the tension, like full horsepower driving. Really want to know the speed I got. But I didn't need to use straps.
Till now, any windsurfing speed are two times of wind speed?
Question 2:
When do you start to use straps? reach some speed? or ? I don't think you use straps on 10 knots condition, do you?
Question 3:
Do I need some track device to record my speed? I am thinking about it.
If I need one, afterwards to check track and speed, don't check on the water,how much for a cheap one? water proof need. I read many related article at GPS part, so many vocabulary I don't understand. Alpha, 50....etc.
Thanks in advance.
Generally no. Far too many variables, not the least of which is that the sail takes the shape of a lifting body when loaded.
you can get a watch like a garmin or even cheaper, but need to get one that allows you to download your session to some app that will show you the stats and the track on a map. If you can get a file out of the watch you can upload the file to KA72.com and it will show you the categories we use for gps team challenge:
2sec is what we use for max speed, it is actually the speed over 2 seconds to average spikes
5x10 is the average of the best 5 10 seconds periods
alpha is a track 500m long that includes a jibe - the entry and exit point should not be more than 50m apart
nm is nautical mile
hr is the distance you cover in your best hour
all the previous categories are in nautical miles (1nm = 1852 meters)
and distance is usually in kms
So wind strength isn't the only factor in max speed. Power available, is a direct relationship to your weight/sail size and skill. For max speed you need a sail that you can just fully sheet in. If it's any bigger you ave to sheet out, you get the same power but with more drag.
The other factor in max speed is drag, this is where skill come in, you have to trim the board and rig for minimum wetted surface area.
This where the straps come in You can be more fully powered up with feet in straps, and you have more control of board trim. I get in the straps as soon as I have enough speed to get my feet that far back, which is usually not long after I start planning.
It sounds like you are really interested, my advice is to join a GPST team
www.gpsteamchallenge.com.au
There are a few Qld teams.
Members will be very helpful, but to post there you need an authorised device. You may be able to get a second hand one, because there's only 2 new on the market at the moment. The GW60 has reliability issues and's about au$360. By far the best is the motion, but that's in short supply.
You could derive a set of formulas statistically if the correlation was good enough to be useful. Participants on GPSTC post the gear they used for a given session and GPS tracks for that session on ka72.com. GPSTC is speed sailing, so if you were to use this data source, the formulas would have that context.
The relationship between wind strength and max speed isn't linear!
As long as you have the ideal sail size, available power remains constant, purely dependant on your weight and skill.
In lighter winds, the gear has to be bigger, so there's more dead weight and more drag, so there's a loss of efficiency. At higher winds, the rider starts to be a significant proportion of drag, so again a loss of efficiency.
As a very rough guide, (I'm only guessing here, and based on my experience of a light weight sailor around 65Kg). Fully powered at 10knots should get around 20kts, (I've never been fully powered at 10kts, I don't have a big enough sail).
20Kts of wind should get you doing 30kts, (for me anyway)
30kts, could get you to 40kts, (haven't made that yet)
And to do 50kts, I think you need a windspeed around the same.
so the ratio goes from 2:1 to 1:1
And that's on the ideal downwind angle, if you're sailing square the numbers are much less
Select to expand quotejn1 said..
You could derive a set of formulas statistically if the correlation was good enough to be useful. Participants on GPSTC post the gear they used for a given session and GPS tracks for that session on ka72.com. GPSTC is speed sailing, so if you were to use this data source, the formulas would have that context.
Trouble is lack of wind strength data
Select to expand quotesegler said..
Generally no. Far too many variables, not the least of which is that the sail takes the shape of a lifting body when loaded.
Thanks.
Select to expand quotepowersloshin said..
you can get a watch like a garmin or even cheaper, but need to get one that allows you to download your session to some app that will show you the stats and the track on a map. If you can get a file out of the watch you can upload the file to KA72.com and it will show you the categories we use for gps team challenge:
2sec is what we use for max speed, it is actually the speed over 2 seconds to average spikes
5x10 is the average of the best 5 10 seconds periods
alpha is a track 500m long that includes a jibe - the entry and exit point should not be more than 50m apart
nm is nautical mile
hr is the distance you cover in your best hour
all the previous categories are in nautical miles (1nm = 1852 meters)
and distance is usually in kms
Hi Powersloshin,
Appreciated for your patient explanation.
Wonderful!
Before I thought different app got different results.
As Decrepit said, the relationship between max speed and wind speed is not linear. Water state, sailor talent, height & weight, board, sail and fin size also effect max speed. For me at around 90kg and 173cm, sailing in flat water, I've recorded the following:
- wind speed: 13kts, Max 2sec speed: 28.8kts, sail: 8.5, board: 137 lt & 82 wide, fin: 46 pointer
- wind speed: 15kts, Max 2 sec speed: 34kts. sail 7.9, board: 137lt & 82 wide, fin: 35 deep weed speed
- wind speed: 20 kts, Max 2 sec speed: 38.6kts, sail: 7.0, board: 115lt & 72 wide, fin: 24 deep delta
- wind speed: 25 to 30 kts, Max 2 sec speed: 38.5kts, sail: 6.2, board: 97lt & 62 wide, fin: 32 pointer
- wind speed: 25 to 30kts, Max 2 sec speed: 39.4kts, sail: 5.7, board: 70lt & 50 wide, fin: 23 deep weed speed
- wind speed: 30 kts, Max 2 sec speed:40.3kts, sail: 5.4, board: 95lt & 55 wide, fin: 25 deep weed speed
At wind speeds under 15kts, the ration of max 2 sec speed to wind speed is over 2.
At wind speed greater than 30kts is approaches 1.
Select to expand quotedecrepit said..
So wind strength isn't the only factor in max speed. Power available, is a direct relationship to your weight/sail size and skill. For max speed you need a sail that you can just fully sheet in. If it's any bigger you ave to sheet out, you get the same power but with more drag.
The other factor in max speed is drag, this is where skill come in, you have to trim the board and rig for minimum wetted surface area.
This where the straps come in You can be more fully powered up with feet in straps, and you have more control of board trim. I get in the straps as soon as I have enough speed to get my feet that far back, which is usually not long after I start planning.
It sounds like you are really interested, my advice is to join a GPST team
www.gpsteamchallenge.com.au
There are a few Qld teams.
Members will be very helpful, but to post there you need an authorised device. You may be able to get a second hand one, because there's only 2 new on the market at the moment. The GW60 has reliability issues and's about au$360. By far the best is the motion, but that's in short supply.
Hi decrepit,
Thank you for your information.
The GPS team challenge website looks lots of data. Great to see many of Grand master aged fellows.
Can you private message me roughly the motion mini's price please?
What I want is, monitor myself, see where or which side need to improve. Give myself short term training direction.
Tracking looks useful. So that I won't lost my training direction. For example, need to practice turning/gybing, or get bigger sized sail, or decrease my board etc.
Select to expand quotejn1 said..
You could derive a set of formulas statistically if the correlation was good enough to be useful. Participants on GPSTC post the gear they used for a given session and GPS tracks for that session on ka72.com. GPSTC is speed sailing, so if you were to use this data source, the formulas would have that context.
ka72 looks so cool.
How wonderful the technology use in water sport, speed water sport.
Must be some relationship between wind speed and surfing speed. I looked up, screen shot two of them and wind seed as well. First one is year best.
Looks wind speed + 20?30knots= actual speed? maybe.
Select to expand quotedecrepit said..
The relationship between wind strength and max speed isn't linear!
As long as you have the ideal sail size, available power remains constant, purely dependant on your weight and skill.
In lighter winds, the gear has to be bigger, so there's more dead weight and more drag, so there's a loss of efficiency. At higher winds, the rider starts to be a significant proportion of drag, so again a loss of efficiency.
As a very rough guide, (I'm only guessing here, and based on my experience of a light weight sailor around 65Kg). Fully powered at 10knots should get around 20kts, (I've never been fully powered at 10kts, I don't have a big enough sail).
20Kts of wind should get you doing 30kts, (for me anyway)
30kts, could get you to 40kts, (haven't made that yet)
And to do 50kts, I think you need a windspeed around the same.
so the ratio goes from 2:1 to 1:1
And that's on the ideal downwind angle, if you're sailing square the numbers are much less
Yes, your conclusion like wind speed + 10 knots roughly.
I will need figure out my skill, based on wind speed to get how much to monitor myself.
Can I ask general how fast speed do you start to use straps please? thanks.
You could be in front strap when board is just planing. Backfoot when board is planing cleanly. So maybe 11-15kt boardspeed.
>>>Select to expand quoteCan I ask general how fast speed do you start to use straps please? thanks.
Here's an example, a 24kt alpha
Min speed here is about 10kts, max about 30. So the cross hair is about where I would have hooked back in to harness and straps, around 13kts. Because I was well powered, I could put weight on the sail, stopping the tail from sinking. If you're not powered up, then you have to get weight forward to stop tail sinking. This will vary depending on board width and volume. A bigger board will allow you to get in straps earlier. A floaty board underpowered possibly less than 15kts.
Select to expand quoteJohn340 said..
As Decrepit said, the relationship between max speed and wind speed is not linear. Water state, sailor talent, height & weight, board, sail and fin size also effect max speed. For me at around 90kg and 173cm, sailing in flat water, I've recorded the following:
- wind speed: 13kts, Max 2sec speed: 28.8kts, sail: 8.5, board: 137 lt & 82 wide, fin: 46 pointer
- wind speed: 15kts, Max 2 sec speed: 34kts. sail 7.9, board: 137lt & 82 wide, fin: 35 deep weed speed
- wind speed: 20 kts, Max 2 sec speed: 38.6kts, sail: 7.0, board: 115lt & 72 wide, fin: 24 deep delta
- wind speed: 25 to 30 kts, Max 2 sec speed: 38.5kts, sail: 6.2, board: 97lt & 62 wide, fin: 32 pointer
- wind speed: 25 to 30kts, Max 2 sec speed: 39.4kts, sail: 5.7, board: 70lt & 50 wide, fin: 23 deep weed speed
- wind speed: 30 kts, Max 2 sec speed:40.3kts, sail: 5.4, board: 95lt & 55 wide, fin: 25 deep weed speed
At wind speeds under 15kts, the ration of max 2 sec speed to wind speed is over 2.
At wind speed greater than 30kts is approaches 1.
Very useful data.
Nearly 20 knots on top of the wind speed, why when wind speed increased, your speed dropped?
Why don't you use big sail when wind speed above 20 knots?
Select to expand quoteolskool said..
You could be in front strap when board is just planing. Backfoot when board is planing cleanly. So maybe 11-15kt boardspeed.
Will try.
Select to expand quoteImax1 said..
I remember going fast , it was soo long ago . When will we get wind again ?
How about this Thur and Fri? looks inviting!
Select to expand quotedecrepit said..
>>>Can I ask general how fast speed do you start to use straps please? thanks.
Here's an example, a 24kt alpha
Min speed here is about 10kts, max about 30. So the cross hair is about where I would have hooked back in to harness and straps, around 13kts. Because I was well powered, I could put weight on the sail, stopping the tail from sinking. If you're not powered up, then you have to get weight forward to stop tail sinking. This will vary depending on board width and volume. A bigger board will allow you to get in straps earlier. A floaty board underpowered possibly less than 15kts.
Thanks for that. Kinda of understand because my experience.
Next goal is to move my weight backwards. Then hook in straps one day.
Select to expand quoteMotsbane said..John340 said..
As Decrepit said, the relationship between max speed and wind speed is not linear. Water state, sailor talent, height & weight, board, sail and fin size also effect max speed. For me at around 90kg and 173cm, sailing in flat water, I've recorded the following:
- wind speed: 13kts, Max 2sec speed: 28.8kts, sail: 8.5, board: 137 lt & 82 wide, fin: 46 pointer
- wind speed: 15kts, Max 2 sec speed: 34kts. sail 7.9, board: 137lt & 82 wide, fin: 35 deep weed speed
- wind speed: 20 kts, Max 2 sec speed: 38.6kts, sail: 7.0, board: 115lt & 72 wide, fin: 24 deep delta
- wind speed: 25 to 30 kts, Max 2 sec speed: 38.5kts, sail: 6.2, board: 97lt & 62 wide, fin: 32 pointer
- wind speed: 25 to 30kts, Max 2 sec speed: 39.4kts, sail: 5.7, board: 70lt & 50 wide, fin: 23 deep weed speed
- wind speed: 30 kts, Max 2 sec speed:40.3kts, sail: 5.4, board: 95lt & 55 wide, fin: 25 deep weed speed
At wind speeds under 15kts, the ration of max 2 sec speed to wind speed is over 2.
At wind speed greater than 30kts is approaches 1.
Very useful data.
Nearly 20 knots on top of the wind speed, why when wind speed increased, your speed dropped?
Why don't you use big sail when wind speed above 20 knots?
As I said, speed is influenced by many factors. The speed on the 7 was achieved at Lake George in perfect conditions. The 6.2 was used at Wellington Pt where the speed run is more technical.
The size of sail you can effectively use in a given wind depends on your leverage which is affected by your weight, height and technique.
Select to expand quoteMotsbane said..
>>>
Why don't you use big sail when wind speed above 20 knots?
As I said earlier, if a sail is too big you go slower. Once you have a sail size that you can only just sheet in, a bigger sail will only increase drag. Power is limited to what you can counter balance.
Select to expand quoteMotsbane said..>>>>>>
Can you private message me roughly the motion mini's price please?
What I want is, monitor myself, see where or which side need to improve. Give myself short term training direction.
Tracking looks useful. So that I won't lost my training direction. For example, need to practice turning/gybing, or get bigger sized sail, or decrease my board etc.
It's extremely rough, numbers slip through this old brain like water down a drain. So I have $350 floating around in there somewhere. But as I said there's a very long delay. The mini motion, without a display is a lot cheaper, that allows you to post, but you still need on the water feedback. The cheapest way, is an old phone. I have a $40 phone from the postoffice, loaded with GPSLogit. The beauty of this it has an audio output, so you can listen to your speed as you sail. But it's no longer on the playstore, although there are a few version floating around here. There's another sailing app that's more directed at racing, I've never used it on the water, but I think it will give you enough info.
There are other smart watches on the market, that can be loaded with custom software, that people use along with the min motion.
Select to expand quoteJohn340 said..Motsbane said..John340 said..
As Decrepit said, the relationship between max speed and wind speed is not linear. Water state, sailor talent, height & weight, board, sail and fin size also effect max speed. For me at around 90kg and 173cm, sailing in flat water, I've recorded the following:
- wind speed: 13kts, Max 2sec speed: 28.8kts, sail: 8.5, board: 137 lt & 82 wide, fin: 46 pointer
- wind speed: 15kts, Max 2 sec speed: 34kts. sail 7.9, board: 137lt & 82 wide, fin: 35 deep weed speed
- wind speed: 20 kts, Max 2 sec speed: 38.6kts, sail: 7.0, board: 115lt & 72 wide, fin: 24 deep delta
- wind speed: 25 to 30 kts, Max 2 sec speed: 38.5kts, sail: 6.2, board: 97lt & 62 wide, fin: 32 pointer
- wind speed: 25 to 30kts, Max 2 sec speed: 39.4kts, sail: 5.7, board: 70lt & 50 wide, fin: 23 deep weed speed
- wind speed: 30 kts, Max 2 sec speed:40.3kts, sail: 5.4, board: 95lt & 55 wide, fin: 25 deep weed speed
At wind speeds under 15kts, the ration of max 2 sec speed to wind speed is over 2.
At wind speed greater than 30kts is approaches 1.
Very useful data.
Nearly 20 knots on top of the wind speed, why when wind speed increased, your speed dropped?
Why don't you use big sail when wind speed above 20 knots?
As I said, speed is influenced by many factors. The speed on the 7 was achieved at Lake George in perfect conditions. The 6.2 was used at Wellington Pt where the speed run is more technical.
The size of sail you can effectively use in a given wind depends on your leverage which is affected by your weight, height and technique.
Thanks again, John!
Select to expand quotedecrepit said..Motsbane said..>>>>>>
Can you private message me roughly the motion mini's price please?
What I want is, monitor myself, see where or which side need to improve. Give myself short term training direction.
Tracking looks useful. So that I won't lost my training direction. For example, need to practice turning/gybing, or get bigger sized sail, or decrease my board etc.
It's extremely rough, numbers slip through this old brain like water down a drain. So I have $350 floating around in there somewhere. But as I said there's a very long delay. The mini motion, without a display is a lot cheaper, that allows you to post, but you still need on the water feedback. The cheapest way, is an old phone. I have a $40 phone from the postoffice, loaded with GPSLogit. The beauty of this it has an audio output, so you can listen to your speed as you sail. But it's no longer on the playstore, although there are a few version floating around here. There's another sailing app that's more directed at racing, I've never used it on the water, but I think it will give you enough info.
There are other smart watches on the market, that can be loaded with custom software, that people use along with the min motion.
I will try my phone in a waterproof bag.
Thanks for advice and information.
I bought a Garmin Forerunner 245 sports watch when they were on special ( about $270? ). You'd have to wait for it to be on special although there are probably others out there that get discounted.
It's not approved so you can't post into the GPSTC comp with it but feedback is terrific especially loaded with windsurfing datafields. It also does heart rate etc so it can confirm that you are buggered because you almost had a heart attack..
You can post your tracks on google Earth.
I find the on water feedback very motivating
Once you get a GPS device expect to be disappointed in your speeds.. It's easy to think you're doing 30kts and 100kms of distance when really you're only doing 23kts and 20kms.. less if you're learning.
Select to expand quoteMotsbane said..>>>
I will try my phone in a waterproof bag.
Thanks for advice and information.
Here's the alternative to GPSlogit, if you can't find a copy.
www.windsporttracker.com
Not sure if that's still in playstore as data is down here.
Select to expand quotedecrepit said..Motsbane said..>>>
I will try my phone in a waterproof bag.
Thanks for advice and information.
Here's the alternative to GPSlogit, if you can't find a copy.
www.windsporttracker.com
Not sure if that's still in playstore as data is down here.
That one looks very comprehensive. The amount of time planing and non planing might be a bit depressing at this time of year..
Select to expand quotesboardcrazy said..
I bought a Garmin Forerunner 245 sports watch when they were on special ( about $270? ). You'd have to wait for it to be on special although there are probably others out there that get discounted.
It's not approved so you can't post into the GPSTC comp with it but feedback is terrific especially loaded with windsurfing datafields. It also does heart rate etc so it can confirm that you are buggered because you almost had a heart attack..
You can post your tracks on google Earth.
I find the on water feedback very motivating
Once you get a GPS device expect to be disappointed in your speeds.. It's easy to think you're doing 30kts and 100kms of distance when really you're only doing 23kts and 20kms.. less if you're learning.
30kts and 100kms of distance when really you're only doing 23kts and 20kms..
Lol.
