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Caribsurf
29th December 2008, 10:16 PM
Hey all and Roger.

Then you new to the sport and try to figure out that sail to rig. I find it difficult then I reading on different forums everybody refer to sail sizes. Like,
- It was a prefect 5.4 day...
But what is a prefect 5.4 day in knots?

I know it depend on you weight and board and so. But why cant sailors say that it was 30knots and a perfect 5.4 day on my evo 100L and my 80kg or something like that.
Guess that you learn that by time and get some more experience. But maybe mods and writers here on Starboard forum can be more aware that its a lot of newbies that read here to and they suck up all the info they can get their eyes on.

ps. Thanks for the best windsurfing forum on the net. Learned a lot here and you always find the answers to your questions here.

Ken
30th December 2008, 02:56 AM
Caribsurf,

There are so many variables, it is impossible to directly relate what you read about to what you would actually use.

Level of sailor experience
Fresh or salt water
waves, chop, flat water, etc
Body weight & height of sailor
Type of board (slalom, freeride, freestyle, wave, formula, long board, etc.)
Weight, volume, width of board
Fin type and size
Type of sail (wave, freeride, slalom, formula, freestyle, etc.)

Everything above will have some impact on choosing your sail size. For example, I sail on inland lakes in Texas. It's not uncommon for a bunch of us to be on the water at the same time using sail sizes anywhere between a 5.7 and a 11.0. One of my buddies who is very light weight on very light custom slalom boards would be on his 5.7 in 12 - 15 knots, while I may be out on my formula board with a 11.0. The rest of the gang on average may be on 7.5's to 9.0's.

When I get to the lake and there are others on the water, I ask what they have been using. I also look at the water and chop to estimate what I will use along with the info. from the other sailors. If the wind was 10 to 20 knots (pretty variable, but normal lake sailing conditions), I could choose to sail my formula 160 on a 9.2 & a formula sail; or an iSonic 111 slalom board with a 7.5 race sail.

Two people, one a novice and one an expert, both the same size and weight on the same board and sail may choose sail sizes 2 to 3 meters apart based on their skill level. The more experience you gain, the bigger sails you can manage and contol.

It just takes a while to figure out what works best for you, and even the experts get it wrong from time to time and have to come in to re-rig another sail.

I hope this helps.

crazychemical
30th December 2008, 03:56 AM
there is on of the guys who frequents the free forum who created a sailcalculator. insert weight and wind and you get a sailrange. for beginners it's a good indicator. Usually when i'm unsure i look at what the others are sailing. Just try to find someone that has a kit that would be simular to yours and make the best copy you can think of. but in the end, it's pure empirical science. Like ken sais, too many factors.

Caribsurf
30th December 2008, 04:44 AM
A good answer...

Thanks for a good answer Ken.
I understand board and fin size is an big factor for choosing you sail. And that other stuff you mention make sens to I guess.

But still one question remains.
Why do a lot of wind surfers refer to their used sail size then they talk about conditions for a session then?
Why not just wright that it was blowing 30knots and I had a 5.2 sail. So everybody understand that its blowing 30knots and can refer to that easier, then just wright it was 5.2 condition.

Or is that some secret windsurfer code so no outsiders can understand that why meen?:)

In da rain CS

Caribsurf
30th December 2008, 04:53 AM
there is on of the guys who frequents the free forum who created a sailcalculator. insert weight and wind and you get a sailrange. for beginners it's a good indicator. Usually when i'm unsure i look at what the others are sailing. Just try to find someone that has a kit that would be simular to yours and make the best copy you can think of. but in the end, it's pure empirical science. Like ken sais, too many factors.

I find it. Looks cool, just that I had to install the root of all evil microsoft exel on my poor mac.
But look grate.

A direct link:
http://www.vims.edu/general/sailpaddle/sailcalculator.xls


And thank you James, his the inventor...

Roger
30th December 2008, 08:44 PM
Hi Caribsurf,
I posted something yesterday, on this topic but somehow it never made it onto the forum.
I agree with Ken and CC.
They make very good points that were part of what I was saying.
One point they didn't cover, that I feel is primary to this issue is windspeed.
Do you have an accurate windspeed meter of some sort?
Many windsurfers have learned to "look at the water" and the surrounding trees, etc
and are able to judge the windspeed fairly accurately, but most do not have any
sort of accurate windspeed information.
So, using your example, if the windspeed is 30 knots and they are perfectly powered on a 5.4 m2 rig how do they know it's actually 30 knots?
My answer is that they do not know.
Windspeed in the 5-10 knot range we can fairly accurately judge.
Windspeed in the 10-15 knot range is pretty easy to judge also.
15-20 knots is more difficult, and over 20 knots becomes very hard
to tell as once the chop starts (at around 12-14 knots) it does indeed
get larger, but geography and fetch (the distance the wind has to act on the surface
of the water) really affect our ability to judge true windspeed.
I only know one guy who wears a wrist mounted wind meter (anemometer) and stops out on the water while sailing to check what wind speed he's sailing in.
So, most of the rest of us are stuck with onshore handheld anemometer information,
information from the nearest weather station or airport, or perhaps information from an onsite service like I-Windsurf that provides pagers that give windspeed and can give you an alarm when the windspeed gets up to your personal minimum.
Nice, but none of this actually measures the windspeed out on the water where we are sailing.
So, having real time accurate windspeed information is very sketchy at best.
There are sailors who would be perfectly powered on 5.4 m2 wave sails in 25 knots, and there are other sailors who are going for slalom speed who might be perfectly powered on a 5.4 m2 race sail at around 30 knots (that's alot of wind), but you might find that 30 knots is better on a 3.8-4.2 m2 rig.
Sail design has changed in the last 12 years and most of us use about 0.5-1 m2 larger modern sails than say we would have used in late 80's early to mid 90's sail designs.
So, as suggested by the others, we could state that we felt perfectly powered in X knots of wind on an X.X m2 rig, but having others take the same combination of sail size and windspeed would probably have them feeling overpowered or underpowered.
Hope this helps,

Caribsurf
31st December 2008, 04:38 AM
Thanks for a good answer and I start to understand the point now. Guess I to concern about the wind speed and it may not be that exact sometimes.



Do you have an accurate windspeed meter of some sort?


I have one in the mast of my boat. So normal I check it every morning then I get up and if the wind is picking up. Or If I just want to see if my guess of the current wind speed is correct. And normally it is. I been sailing for ten years soon, so I getting pretty good at judging the wind speed.

Ken
31st December 2008, 04:48 AM
Caribsurf,

To answer your question -

"But still one question remains.
Why do a lot of wind surfers refer to their used sail size then they talk about conditions for a session then?
Why not just wright that it was blowing 30knots and I had a 5.2 sail. So everybody understand that its blowing 30knots and can refer to that easier, then just wright it was 5.2 condition.

Or is that some secret windsurfer code so no outsiders can understand that why meen?"

No code, just a quick reference to what sail they used. As Roger says, judging wind speed when it is 20 to 30 knots is pretty hard, but if a 5.0 sail worked well for the day, then we just say that it was a 5.0 day. The reality is that some may have been on a 4.2and others on a 6.2, and the wind may have ranged from 15 to 30 knots. Inland lake sailing offers variable winds, it's never steady, just up and down. About two weeks ago, I was out on a "4.5 day", but at times I was slogging (not planing) and at other times I was overpowerd.

In the Dallas, Texas area, iWindsurf.com posts reading from 11 airports and three lakes, so before I go out, I know what the wind is doing. I petty much know what I will rig before I get to the lake.

The anemometer idea fthat Roger suggests is a good idea for beginners or intermediates, but eventually, you will just know what to use. I have two, but I haven't used them in several years.