When a sail too big?

When a sail too big?

Post by jt.. » Thu, 13 Jun 1991 00:49:18



Quote:
(felix.cabral) writes:

> The problem is how can you tell a sail is to big?

If you have a low volume board it will be very difficult to waterstart a large
sail in light winds. In Hatteras you can stand everywhere so there's no
problem, but I can imagine trying to waterstart a 7.5m2 on a 8'6" wave board in
open ocean conditions!

I guess it's too large if you arn't having any fun...

-Jthan.

 
 
 

When a sail too big?

Post by Kent Mult » Thu, 13 Jun 1991 08:24:50


Quote:

> (felix.cabral) writes:

>> The problem is how can you tell a sail is to big?

Some people say, "I can't use a 7m sail on my 9' board because it's too heavy,"
but I'm skeptical of this.  The difference in weight between a 7m and a 4 or 5
is so small, compared to the total of board, rig, and especially RIDER, I don't
think it would matter to 99% of us.

A better question might be, "When is the board too small?"  Look at it this
way:  You can always get planing _on your reaches_ if you put a big enough
sail on the board, but when you turn downwind to start a jibe, you lose the
"leverage" effect that gives you your speed, and will probably start to sink.
Also, if you're using a big sail on a little board, you're going to have more
of a struggle to stay on it during lulls.

I have an 8'6" board that I have used with a 6m campbered sail, and it works
fine, except in the lulls.  (I must admit that the board is a Velocity "Speed
Spoon" which is quite floaty for its length.)  I will probably get around to
trying my 7m on that board, but I'm waiting for a day when the wind is nice
and steady (minimal lulls).

Have fun!

[=====================================================================]
 |  Kent Multer                 alias:              Maruta Ken       |
 |                                                                   |
 |  Magic Metal Productions         _|___    _____      /:\ ||       |
 |  P. O. Box 871895                `|. |   |__|__|     [|] ||       |
 |  Dallas, TX  75287                /  \/  |__|__|     /^\  /       |
 |                                                                   |
 |  (214) 394-0541                  "Sword of the Round Rice Paddy"  |
[=====================================================================]

 
 
 

When a sail too big?

Post by Kent Mult » Fri, 14 Jun 1991 05:17:12

Quote:
>>> The problem is how can you tell a sail is to big?

> What about spin out?

Spin-out occurs at the fin.  If you have the right fin (more wind = smaller),
and you have good balance and control, you can prevent it.  I don't think it's
really related to the sail size -- although, certainly it's true that, as you
go to bigger and bigger sails for a given wind speed, at some point your
whole board and rig will get what I might call "structurally" overpowered,
i.e., it's not your lack of skill; nobody can use a 7m when it's blowing 20  
to 30!  (Unless they're very big and heavy!)

Quote:
> Another point that nobody has made:
> When you are powered up in 10 knotts, it is not unusual for 15 knott (or
> more) gusts, which represents a 50% or more increase in the wind.  The
> high wind comparison to this would be say 40 knotts with gusts of 60+.

I disagree strongly with this.  The behavior of the wind is not that
mathematical.  Haven't you ever noticed that it seems that there are some days
when everybody is using, say, a 4.5 -- regardless of their size?
I'm not sure why, except that obviously, the physics of windsurfing is very
complex since it involves water as well as air, and both the sail and the
board/fin can rotate independently in all 3 axes.

[=====================================================================]
 |  Kent Multer                 alias:              Maruta Ken       |
 |                                                                   |
 |  Magic Metal Productions         _|___    _____      /:\ ||       |
 |  P. O. Box 871895                `|. |   |__|__|     [|] ||       |
 |  Dallas, TX  75287                /  \/  |__|__|     /^\  /       |
 |                                                                   |
 |  (214) 394-0541                  "Sword of the Round Rice Paddy"  |
[=====================================================================]

 
 
 

When a sail too big?

Post by Hens Vanderscho » Fri, 14 Jun 1991 02:00:55

Quote:

> (felix.cabral) writes:

>> The problem is how can you tell a sail is to big?

What about spin out?  I find that a large sail on a small board creates
more lateral force on the tail.  Augmenting the problem is the fact that
in light winds, I find myself trying to get upwind more often (when
spinout is most frequent).

Another point that nobody has made:
When you are powered up in 10 knotts, it is not unusual for 15 knott (or
more) gusts, which represents a 50% or more increase in the wind.  The
high wind comparison to this would be say 40 knotts with gusts of 60+.
I think most would agree that such conditions might be slightly difficult
to sail in, especially if the high-wind gusts had the low-wind gust
nature (ie. short puffs).  Unless of course, you enjoy a good launch/slam.

- Hens

 
 
 

When a sail too big?

Post by Erich Hegenberg » Fri, 14 Jun 1991 21:46:35

Quote:

>i.e., it's not your lack of skill; nobody can use a 7m when it's blowing 20  
>to 30!  (Unless they're very big and heavy!)

Being big and heavy doesn't necessarily mean you can carry a bigger sail
- because of scaling factors, muscle strength does not increase with
size as quickly as weight does (ever hear of a little oaf?). This puts a
larger person in the unfortunate position of flying a rig that's too big
to handle, but still too small to waterstart, unless they're very
sensitive with the sheet! :)
 
 
 

When a sail too big?

Post by Hens Vanderscho » Sat, 15 Jun 1991 00:52:04

Quote:

> >>> The problem is how can you tell a sail is to big?
> > What about spin out?

> I don't think it's really related to the sail size -

I think you definately missed my point.  For 2 reasons, spinout problems
increase with sailsize.
1.  Due to higher probability of slogging (light wind blues), which
  invariably puts me downwind of my course, I need to point higher when
  powered-up to compensate for the windward loss.  Sailing closer to
  the wind increases the frequency of spinout.
2.  Larger sails move the CE back (towards the tail) as is witnessed by
  the fact that I have to adjust my harness lines when I change sails.
  With the CE closer to the tail, there is more lateral force on the
  fin which is the force responsible for spinout.

Quote:
> > Another point that nobody has made:
> > When you are powered up in 10 knotts, it is not unusual for 15 knott (or
> > more) gusts, which represents a 50% or more increase in the wind.  The
> > high wind comparison to this would be say 40 knotts with gusts of 60+.

> I disagree strongly with this.  The behavior of the wind is not that
> mathematical.  Haven't you ever noticed that it seems that there are some days
> when everybody is using, say, a 4.5 -- regardless of their size?

Yes, but have you ever seen days where everybody is using a 7.0m?...That's
my point.  You don't hear wind reports of "35 to 70 mph," but you often hear
"5 to 10 mph," both of which represent a 100% difference between extremes!
Stronger winds are more consistent (for the most part).

 - Hens

 
 
 

When a sail too big?

Post by Kent Mult » Sat, 15 Jun 1991 01:34:45


Quote:

>>i.e., it's not your lack of skill; nobody can use a 7m when it's blowing 20  
>>to 30!  (Unless they're very big and heavy!)
> Being big and heavy doesn't necessarily mean you can carry a bigger sail
> - because of scaling factors, muscle strength does not increase with
> size as quickly as weight does (ever hear of a little oaf?). This puts a
> larger person in the unfortunate position of flying a rig that's too big
> to handle, but still too small to waterstart, unless they're very
> sensitive with the sheet! :)

Your ideas are very contrary to my own experiences.  It's quite well known
that, in general, bigger people use bigger sails, especially on relatively
light-wind days (notwithstanding my earlier comment about days when everyone
uses the same sail; as I said, the physics of this is complex).  Also, many
smaller people actually wear weighted harnesses when racing, in order to be
able to handle more sail.

Re your comment about "too big to handle, but too small to waterstart:"  I
can't imagine how this could ever be true, unless you were pretty poor at
waterstarting!

You're probably correct, though, that skill is more important than size.  Many
times I get to the lake, and people are coming off the water saying, "Oh, I
was using my 5.0, and it's a little too much!" -- but I go out with my 6.0 and
have no trouble.

 
 
 

When a sail too big?

Post by Erich Hegenberg » Sat, 15 Jun 1991 08:12:36

Quote:

>Your ideas are very contrary to my own experiences.  It's quite well known
>that, in general, bigger people use bigger sails, especially on relatively
>light-wind days (notwithstanding my earlier comment about days when everyone
>uses the same sail; as I said, the physics of this is complex).  Also, many
>smaller people actually wear weighted harnesses when racing, in order to be
>able to handle more sail.

>Re your comment about "too big to handle, but too small to waterstart:"  I
>can't imagine how this could ever be true, unless you were pretty poor at
>waterstarting!

>You're probably correct, though, that skill is more important than size.  Many
>times I get to the lake, and people are coming off the water saying, "Oh, I
>was using my 5.0, and it's a little too much!" -- but I go out with my 6.0 and
>have no trouble.

Oh, well, one out of three, and points off for English, not to mention
the complex physics! ;)
 
 
 

When a sail too big?

Post by William Warburt » Sat, 15 Jun 1991 23:37:08

|> > Being big and heavy doesn't necessarily mean you can carry a bigger sail
     ....
|> > to handle, but still too small to waterstart, unless they're very
|> > sensitive with the sheet! :)
|>
|> Your ideas are very contrary to my own experiences.  It's quite well known
|> that, in general, bigger people use bigger sails, especially on relatively
|>
|> Re your comment about "too big to handle, but too small to waterstart:"  I
|> can't imagine how this could ever be true, unless you were pretty poor at
|> waterstarting!

 I think that you are wrong. I agree with the first poster here.

 My girlfriend is quite 'big boned', as they say. We are about the same weight
but I am considerably stronger. It is a lot more difficult for her to
waterstart because her "power to weight" ratio is lower.
 Basically, the band of sail sizes that is big enough for her to be able to
waterstart and that is small enough for her to be able to hang on to is much
narrower than for me. This is not normally the case for women because they are
generally much lighter than men and consequently can use a smaller sail (don't
need as much power to waterstart/plane).
|>
|> You're probably correct, though, that skill is more important than size.  Many
|> times I get to the lake, and people are coming off the water saying, "Oh, I
|> was using my 5.0, and it's a little too much!" -- but I go out with my 6.0 and
|> have no trouble.

 This is technique. I agree that technique is by far the most important factor
(ie if my girlfriend's technique was better then she wouldn't have a problem).
 From this situation I would deduce that some or all of the following is true
of your windsurfing compared to the windsurfing of the other sailors you
quote above:
                You are a better sailor.
                You have better sails.
                You have a faster/quicker board (speed vs acceleration).
                You are stronger and fitter than them.

If anyone out there has tips for large, relatively weak sailors I would love
to hear them. Hopefully I can pass them on to Judy.

Thanks,
        W.

Oh aye: Baxter 270 wave,VitSea 292,Tiga Slalom & half a Fanatic Ultra Bee!

                                       ( the back half BTW- I buy the fins :-)

 
 
 

When a sail too big?

Post by Kent Mult » Sun, 16 Jun 1991 06:02:57


Quote:

>>If anyone out there has tips for large, relatively weak sailors I would love
>>to hear them. Hopefully I can pass them on to Judy.

> I have found that moving the boom lower on the mast makes waterstarting
> easier.  A couple of inches can make a big difference.  

Yes, definitely.  Also, in order to waterstart in relatively light wind,
it's _very_ important to keep your body's center of gravity low until you're
completely out of the water.  That means:  keep your arms straight, and bend
at the knees and hips so that you come onto the board in a low, almost-    
squatting position; then stand up.  Many people have a tendency to keep their
legs straight and bend their arms, like doing a chin-up on the boom.  That    
only works when the wind is quite strong, because it requires the sail ,
rather than the board, to lift you out of the water.

Regarding myself (in response to an earlier post):  I've been sailing 4 years,
so I'm solidly in the intermediate-to-advanced skill area.  
That comment about others being overpowered with a 5m, when I'm doing fine
with a 6m, _did_ sound a bit boastful; sorry!  But then, I've always
concentrated on having a smooth, effortless style; cooperating with the wind,
waves, board, etc., rather than trying to bend them to my will.  I find that,
even in high wind, you can relax and not get pooped if you're in tune with
the elements.

Also, I'm tall and thin, which some people are now saying is the ideal
build for a windsurfer.  I can't say since I've never sailed with any other
type of body! :-)

 
 
 

When a sail too big?

Post by Douglas L. Yanaga » Sun, 16 Jun 1991 02:37:39

Quote:

>If anyone out there has tips for large, relatively weak sailors I would love
>to hear them. Hopefully I can pass them on to Judy.

I have found that moving the boom lower on the mast makes waterstarting
easier.  A couple of inches can make a big difference.  Of course, once
you've got your waterstarts down, you want to adjust your setup so that
you're comfortable harnessed and strapped in.

- Doug

 
 
 

When a sail too big?

Post by Kirk Lindstr » Wed, 19 Jun 1991 01:13:33

Quote:
>If anyone out there has tips for large, relatively weak sailors I would love
>to hear them. Hopefully I can pass them on to Judy.

>    W.
>Oh aye: Baxter 270 wave,VitSea 292,Tiga Slalom & half a Fanatic Ultra Bee!

Sail as much as possible when the wind blows, swim 2-3K yards 3x a week or
do Starmaster and Nautalis during the winter, eliminate as much fat from
your diet as possible, don't eat junk OR fast food (6 months since I've had
a pizza), and KEEP AT IT FOR THE REST OF YOUR LIFE, one day at a time.  

How do I know?  I've been doing just that for the past 18 months and I've
lost about 6 inches on my waist, 32 lbs, and added several inches to my
bicepts and shoulders (not to mention I feel 10 years younger!).

Try learning to waterstart a 248 lb body with a 5.7 sail in 12 knots of
wind.

Besides fitness and technique, flexibility whould also help with waterstarting
Also, I wasn't as flexible until I lost some belly mass which allows me
to  now bend over and touch my palms to the floor.

-Kirk out
9'9" Velocity, 8'8" Challange Flex & 11'6" Malibu (& looking at a 9' CFX)
Wt 216#, Ht. 6'0", Home water => Coyote Pt, SF Bay, Cailf.

 
 
 

When a sail too big?

Post by Booker Ben » Thu, 20 Jun 1991 09:21:43

Quote:


>> (felix.cabral) writes:

>>> The problem is how can you tell a sail is to big?

>What about spin out?  I find that a large sail on a small board creates
>more lateral force on the tail.  Augmenting the problem is the fact that
>in light winds, I find myself trying to get upwind more often (when
>spinout is most frequent).

-Get a bigger fin , I mean, really big, 13 inches ( 35 cm ) is the norm
around here. The pointier , the better.

Quote:

>Another point that nobody has made:
>When you are powered up in 10 knotts, it is not unusual for 15 knott (or
>more) gusts, which represents a 50% or more increase in the wind.  The
>high wind comparison to this would be say 40 knotts with gusts of

60+.

- Not Quite: The force on a foil ( sail, fin , lifting body) is
given to a rough approximation by

        Area * velocity**2 ~ force

So the percentage change in the force is the same , however even
a 100% increase in not much is still not much. The amount of force
available at 40 knots is an order of magnitude larger than any
reasonable force you can generate at 10-15 knots.  I regularly sail an
8m or 10m sail in gusts of up to 15 knots without much problem. Of course,
it's been a long time since I had problems with getting launched.
It seems to be a phase that you go through, once you figure it out
you don't get launched or backwinded unless you're not paying
attention.  

- I think the key to whether your sail's too big for your board is if
you can maintain a planing jibe. I've seen people sail 9m meters on a
9.0 board and they can plane in just about anything, but they can't
stay on a plane during a jibe. Lot's of people back and forth around
here with 9.4 - 9.8 boards and 8m sails , but very few do planing
jibes. I have a Seatrend 9.5 that loves to jibe on flat water, but I
was never able to get it to really work well with my 8.0 sail. I have
since bought a used fanatic Ultra Cat '87 and this is now my jibing
machine. I love laying down big carving jibes in 10 knots of wind.
I've heard the newer ones have harder rails so they might not be as
much fun. For me, the most fun thing on flat water is to carve jibes.
Speed runs are cool, but they get boring pretty quickly. BWT, since
I can put a smaller fin on the ultra cat than on 9.6 slalom board
with the same size sail, I give up very few knots in the speed race.
The big fins required to use large sails on a short board really slow
it down.

- Booker C. Bense