Spinouts?

Spinouts?

Post by Ray Seiffe » Wed, 03 Jun 1992 04:06:43


Help!!  Can someone give me an explanation for spin out?  Here's the scenario:

    Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
    of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
    to go to windward pushing on the fin, weight forward in the harness
    when suddenly, without warning, I'm going sideways.  

    I may have been on the downhill side of a swell at the time.  I was
    so surprised, I sort of lost that part of the trip.

Any enlightenment would be appreciated.

Ray Seiffert

 
 
 

Spinouts?

Post by Jack Greenba » Wed, 03 Jun 1992 10:49:40

   Help!!Can someone give me an explanation for spin out?  Here's the scenario:

       Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
       of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
       to go to windward pushing on the fin, weight forward in the harness
       when suddenly, without warning, I'm going sideways.  

... too much force on the fin with not enough speed.

Spinout occurs when the fin stalls, which means that the water is no
longer flowing smoothly over the fin. It's just like when an airplane
falls out of the sky when going to slow for the angle of attack. To get
things to work again you need to "reattach" the fin, that is get the
water to flow over it smoothly again. Slotted fins do this
automatically.  Otherwise it's just like coming out of a waterstart and
needing to get the board moving the right direction.  Sanding the
leading edge smooth can also have a dramatic effect in preventing
spinout by making the water flow more smootly over the fin.

There has been alot of discussion about learning to go upwind, so here's
a thread from the end of last summer on the topic
(bears.ece.ucsb.edu:/pub/windsurf/threads/upwind). I'm at the same point
as most folk asking about going upwind (i.e. dunk jibe master, walk
upwind on the beach). Rereading this thread seems to be helping me in
that I'm going upwind much better now that I've learned to get my weight
very far forward. Tomorrow (wind and grad advisor willing) I'll try
moving my mast track up a bit.

-- Jack

p.s. I love my True Ames weed fin. I hardly notice the kelp, and when it
spins out I deserved it.

p.p.s If someone wants to write a more concise FAQ then let me know.

------------------------------------------------------------------------


Date: Thu, 13 Feb 1992 05:45:31 GMT
Subject: Re: Re: Sailing a short board upwind

Organization: HP Labs, High Speed Electronics Dept., Palo Alto, CA
Newsgroups: rec.windsurfing

Quote:
> Are there any tips on how to sail back up the wind?  I appreciate that
> it is not possible to sail as close to the wind on a short board as it is
> on a long board but any movement upwind would be useful.

[ Maybe FAQ material... I asked this last summer and got some great help
here. ]

The most important thing is to keep your speed up so you plane well;
it's much harder (and less fun) to slog upwind.  You must point up as
close to the wind as possible but maintain your plane.  This often means
pointing closer and closer until you start to lose your plane, then
falling off (turning a bit downwind) to rebuild your speed.

The second thing is to let your board heel to leeward (that is, sink the
downwind edge a bit).  This lets you use the whole leeward rail (well,
as much as is in the water) to provide lateral resistance instead of
just your fin.  The problem I found was that heeling to leeward causes
your board to turn downwind (normal footsteering when planing).  The
trick here is to rake your rig back towards the tail in order to move
the sail's center of force back, which tries to turn you upwind.
Balancing these lets you plane in a straight line with the board heeled
to leeward.

The last thing is to use the right fin.  I learned to go upwind last
summer with the above techniques using a ~speed fin; I was amazed to
discover recently how much easier it is to go upwind with a slightly
larger pointer fin.  The pointer, however, is too much fin for high
winds (5.0 or better), so I'm now changing between two fins on my 9'0"
board, depending on conditions; it makes it much more versatile.

A smaller issue is that in choppy water, you can increase your speed
and thus how high you can point by steering around the bigger waves
rather than just plowing over them.

Finally: practice, practice, practice...

When you do these things, the next thing you discover is spinout!
But that's another FAQ.

Ken "just the FAQs, ma'am" Poulton


Date: Tue, 20 Aug 1991 16:51:32 GMT
Subject: Sailing Upwind Problems

Organization: Wyse Technology
Newsgroups: rec.windsurfing
Distribution: usa

Well, slowly but surely I'm making good progress. Waterstarts are a snap,
as is getting in and staying in the straps. However, I"ve noticed that my
ability to go upwind is definitely below par as I frequently wind up
in the swin area at Coyote and often go kelp swimming in Santa Cruz.

I use an old 9'2" Seatrend with a nice slalom fin and a new semi-wave 8'10"
custom board with a slotted wave fin.

I know better than to blame my equipment, although I am thinking of getting a
nice big race fin just for the hell of it.

I need help, especially in lighter winds. When I am totally powered up I don't
seem to heve too many problems, but when the wind is lighter, the good sailors
go upwind, and I drift downwind.

Any tips on stance, rigging, etc...  much appreciated.

Jim Munro


Date: Wed, 21 Aug 1991 09:44:27 GMT
Subject: Re: Sailing Upwind Problems

Organization: HP Labs, High Speed Electronics Dept., Palo Alto, CA
Newsgroups: rec.windsurfing

Quote:
> Well, slowly but surely I'm making good progress. Waterstarts are a snap,
> as is getting in and staying in the straps. However, I"ve noticed that my
> ability to go upwind is definitely below par as I frequently wind up
> in the swin area at Coyote

Funny, I was noticing the exact same thing this afternoon.  I sailed
upwind as much as I could (against the flood tide) for an hour and a
half on a mostly-powered 5.7 (9'0 CFX board, 11.5" Rainbow fin) and
still found myself sailing back though the corner of the swimming area.
That's better than walking back from the far downwind end of the swim
area (last month's problem) but not exactly ideal.  I will note that on
an ebb tide, going upwind was easy, but I'd also like some upwind
pointers (so to speak).

Ken Poulton


Date: Wed, 21 Aug 1991 15:42:34 GMT
Subject: Re: Sailing Upwind Problems

Organization: Shredding the water of SF Bay, HP-OCD
Newsgroups: rec.windsurfing

To sail up wind against a flood tide, I've found working on the following
progressive steps to work for me:

#1  Try moving your mast forward 2 inches or more.  Move it back as you
    get better.
#2  Stay on a plane, if you slow down bear off to build up speed and point
    again
#3  stay in footstraps and rail the board leeward
#4  Keep the board ON THE WATER - jumping chop causes major spin-out unless
    you turn downwind.  (especially on fast, new epoxy boards 8=O ).
#5  Practice

.
.
.
#N  Practice

-Kirk out


Date: Wed, 21 Aug 1991 19:54:42 GMT
Subject: Re: Sailing Upwind Problems

Organization: Wyse Technology
Newsgroups: rec.windsurfing


Quote:

>Funny, I was noticing the exact same thing this afternoon.  I sailed
>upwind as much as I could (against the flood tide) for an hour and a
>half on a mostly-powered 5.7 (9'0 CFX board, 11.5" Rainbow fin) and
>still found myself sailing back though the corner of the swimming area.
>That's better than walking back from the far downwind end of the swim
>area (last month's problem) but not exactly ideal.  I will note that on
>an ebb tide, going upwind was easy, but I'd also like some upwind
>pointers (so to speak).

        I did not know until recently that the tides at Coyote Point
        produce a significant current which can sweep you downwind pretty
        fast. THis accounts fo the days when I just don't seem to be able to
        go even SLIGHTLY upwind!

        However, I still find myself significantly downwind of most decent
        sailors under almost any circumstances.

        Jim MUnro


Date: Thu, 22 Aug 1991 00:42:20 GMT
Subject: Re: Sailing Upwind Problems

Organization: Olivetti Research California
Newsgroups: rec.windsurfing


Quote:
> Funny, I was noticing the exact same thing this afternoon.  I sailed
> upwind as much as I could (against the flood tide) for an hour and a
> half on a mostly-powered 5.7 (9'0 CFX board, 11.5" Rainbow fin) and
> still found myself sailing back though the corner of the swimming area.
> That's better than walking back from the far downwind end of the swim
> area (last month's problem) but not exactly ideal.  I will note that on
> an ebb tide, going upwind was easy, but I'd also like some upwind
> pointers (so to speak).

   One thing to keep in mind is that sailing close hauled, pointing
as high as possible, you will be going slower. This is the slowest
point of sail. I sail on a Tiga 280, 9'1" 115 liters, with a 10 3/4"
True Ames Race fin and 89 model Waddell Race Sails. I can get up wind
on Flood, Ebb and slack tides even when I cannot get on a plane. I sail
at 3rd Ave and Coyote Point.
   You need to be able to "feel" the wind, not just point at some point
on shore. Practice pointing as high as possible and maintaining that angle
to the wind. If you are dropping off of a plane point a little lower. If
you are spinning out when going up wind try moving your mast track
farther forward. You should have a comfortable sailing ...

read more »

 
 
 

Spinouts?

Post by Kirk Lindstr » Wed, 03 Jun 1992 07:00:33

Quote:
>Help!!  Can someone give me an explanation for spin out?  Here's the scenario:

>    Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
>    of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
>    to go to windward pushing on the fin, weight forward in the harness
>    when suddenly, without warning, I'm going sideways.  

>    I may have been on the downhill side of a swell at the time.  I was
>    so surprised, I sort of lost that part of the trip.

>Any enlightenment would be appreciated.

>Ray Seiffert
>----------

My guess is that 11.5 inches is too short for a 5.7.  I use a 13" pointer
with that size sail.  Also, when going over chop it is easyier for air
to attach to the fin leading to spinout.  I try to absorb it by lifting
my board with my legs as I go over rather than just pushing through
which seems to help me not spinout so much in chop.  Also, in lulls it
seems easier to spin out if you are way powered then suddenly 50% less
wind which is common at the PowerLines at Sherman Island.  Last week on
a 5.1 at the Power Lines, I found that bearing off in the lulls fixed
that problem as well as putting more weight on my front foot.

Kirk out

 
 
 

Spinouts?

Post by srgxnb » Wed, 03 Jun 1992 19:01:19

Quote:

>Help!!  Can someone give me an explanation for spin out?  Here's the scenario:

>    Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
>    of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
>    to go to windward pushing on the fin, weight forward in the harness
>    when suddenly, without warning, I'm going sideways.  

>    I may have been on the downhill side of a swell at the time.  I was
>    so surprised, I sort of lost that part of the trip.

>Any enlightenment would be appreciated.

One suggestion I've found useful in keeping the board on the water which
maintains speed and reduces the chance of spinout is to imagine there's
a roof a couple of inches above your head and try not to hit it - ie
bend your knees to follow the chop.

Quote:
>Ray Seiffert


regards
Bruce
 
 
 

Spinouts?

Post by Nick_Nik » Thu, 04 Jun 1992 10:55:25

Quote:

>Help!!  Can someone give me an explanation for spin out?  Here's the scenario:

>    Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
>    of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
>    to go to windward pushing on the fin, weight forward in the harness
>    when suddenly, without warning, I'm going sideways.  

>    I may have been on the downhill side of a swell at the time.  I was
>    so surprised, I sort of lost that part of the trip.

>Any enlightenment would be appreciated.

>Ray Seiffert


This can be and no doubt has been a FAQ.

The solution is to go to either a smaller sail (so you are not overpowered)
or a smaller fin. The fin gives you lift but its lift component of
the force is being overcome by the opposite force vector from the sail.

Bear in mind you will get less lift from the smaller fin. You may also
have a technique problem. I would not push on the fin but rather use
the back foot to keep the board either flat or the windward rail up.

Good sailing.....

--
-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

Australian Graduate School of Management,       Tel: 61 2 931 9263
P.O. Box 1, Kensington. N.S.W. 2033.            Fax: 61 2 662 7621

 
 
 

Spinouts?

Post by Joel Cla » Fri, 05 Jun 1992 00:38:28

Quote:



}>>Help!!  Can someone give me an explanation for spin out?  Here's the scenario:
}>>
}>>    Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
}>>    of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
}>>    to go to windward pushing on the fin, weight forward in the harness
}>>    when suddenly, without warning, I'm going sideways.  
}>>
}>>Any enlightenment would be appreciated.
}>>
}>>Ray Seiffert

}>This can be and no doubt has been a FAQ.
}>
}>The solution is to go to either a smaller sail (so you are not overpowered)
}>or a smaller fin. The fin gives you lift but its lift component of
}>the force is being overcome by the opposite force vector from the sail.
}
}Sorry Nick but I have to disagree about the fin. I won't go into the technical
}specifics but it has been my experience that too small a fin
}(for the sail size) will increase the chances for spinouts.
}
}If the fin is too small the sails power will in effect cause you to put more
}pressure on the fin (unless your technique is perfect). Small fins with big
}sails cannot handle the load and will easily spinout.

What I have found is a larger fin will help avoid spinouts in the case of

Quote:
}larger sails.

>--

>AT&T Bell Labs       {  att!mtgzz!felixc  }       a rad board, rad waves,
>Middletown,NJ        {    (908)957-5081   }       and a company sickday!"

Could it be you are both right?

        As the sail size increases the fin size should increase.

        As the board speed increases the fin size should decrease.

If you are planing in the 20-25mph range with a 5.0 sail, doing fine
and the wind picks up and board speed increases to 30-35mph to avoid
spin out you could: reduce sail size OR reduce fin size depending on
your sail and how overpowered you are.
If instead the wind dropped you would both: increase sail & fin size.
Of course there are probably about 16 other adjustments you could do
for optimum performance. :-)

joel clark

 
 
 

Spinouts?

Post by felix.cabr » Thu, 04 Jun 1992 21:58:37


Quote:

>>Help!!  Can someone give me an explanation for spin out?  Here's the scenario:

>>    Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
>>    of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
>>    to go to windward pushing on the fin, weight forward in the harness
>>    when suddenly, without warning, I'm going sideways.  

>>    I may have been on the downhill side of a swell at the time.  I was
>>    so surprised, I sort of lost that part of the trip.

>>Any enlightenment would be appreciated.

>>Ray Seiffert

>This can be and no doubt has been a FAQ.

>The solution is to go to either a smaller sail (so you are not overpowered)
>or a smaller fin. The fin gives you lift but its lift component of
>the force is being overcome by the opposite force vector from the sail.

Sorry Nick but I have to disagree about the fin. I won't go into the technical
specifics but it has been my experience that too small a fin (for the sail size)
will increase the chances for spinouts.

If the fin is too small the sails power will in effect cause you to put more
pressure on the fin (unless your technique is perfect). Small fins with big
sails cannot handle the load and will easily spinout.

What I have found is a larger fin will help avoid spinouts in the case of
larger sails. On the other hand the better fins will also reduce spinouts.
I used a stock fin on my Presto and found myself spinning out in the chop
while sailing overpowered. I then put on a Rainbow RS 3 (G10) fin and had
a hard time causing spinouts. The difference in fins is about $120. The
stock fin cost about $40 while the RS 3 cost $160. BTW, the fins are about
the same size (13").

--

AT&T Bell Labs       {  att!mtgzz!felixc  }       a rad board, rad waves,
Middletown,NJ        {    (908)957-5081   }       and a company sickday!"

 
 
 

Spinouts?

Post by Ned Stoffel 213 » Fri, 05 Jun 1992 08:38:07


|> >
|> >The solution is to go to either a smaller sail (so you are not overpowered)
|> >or a smaller fin. The fin gives you lift but its lift component of
|> >the force is being overcome by the opposite force vector from the sail.
|>
|> Sorry Nick but I have to disagree about the fin. I won't go into the technical
|> specifics but it has been my experience that too small a fin (for the sail size)
|> will increase the chances for spinouts.
|>
|> If the fin is too small the sails power will in effect cause you to put more
|> pressure on the fin (unless your technique is perfect). Small fins with big
|> sails cannot handle the load and will easily spinout.
|>

I agree with Felix -- if you are spinning out you want to go for either a bigger
fin or a better fin.  I can't imagine a plausible explanation for why a smaller
fin would prevent spinout.  Taken to the extreme, such an argument would say
that you could eliminate spinout by going to no fin at all!  However, I have
read the same smaller-fin advice in an article in windsurf magazine, and IMHO,
the author did't know beans about spinout or what causes it.

Ned

 
 
 

Spinouts?

Post by JOHNMAC*DOUGALL TRIUMF OPERATIO » Fri, 05 Jun 1992 13:28:00

The first thing I would check after experiencing spin-out is look for scratches
or other damage on the fin.  If the tip is chewed up from scraping on the beach
it can cause the flow to detach across the whole fin resulting in spin-out.
 
 
 

Spinouts?

Post by Tom Alber » Thu, 04 Jun 1992 23:52:19


Quote:
>     Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
>     of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
>     to go to windward pushing on the fin, weight forward in the harness
>     when suddenly, without warning, I'm going sideways.  

        Hello Ray -

        There are a lot of things that induce spinout.  

        Fin too small.
        Fin not smooth.
        Sailor pushing sideways on the fin.
        Sailor sinking the windward rail (exposing the leeward to air).

        To work windward, get the sail back (aft) as much as possible and
        keep the board flat (or slightly seemingly leeward).

        What this does is gets more board out of the water which makes
        you go faster while all the weight is on a smaller area of the
        board.  This keeps the fin in the water better.  I think a fin
        which is angled down and leeward (because the board has the
        windward rail down) spins out faster than a fin which is vertical.
        Sailing this way also allows the sailor to push with a more
        forward vector - not so much sideways pressure.

        Most of this advice assumes adequate power (you said you were
        overpowered).  In less than powered conditions, the advice is
        a little different.

        tom.

 
 
 

Spinouts?

Post by Tom Alber » Sat, 06 Jun 1992 23:24:07


Quote:

> Could it be you are both right?

>    As the sail size increases the fin size should increase.

>    As the board speed increases the fin size should decrease.

> If you are planing in the 20-25mph range with a 5.0 sail, doing fine
> and the wind picks up and board speed increases to 30-35mph to avoid
> spin out you could: reduce sail size OR reduce fin size depending on
> your sail and how overpowered you are.

        It's true that as board speed increases, you can/should reduce
        fin size, but not to avoid spinouts.  Fin too big is another
        problem which is excesive lift/drag.  If he's spinning out,
        going to a smaller fin will not help, unless the smaller fin
        is a better fin; i.e. better foil or smoother surface.

        As I said before, he needs to make other corrections which
        include: bigger fin or better technique.

 
 
 

Spinouts?

Post by Thomas SM We » Sun, 07 Jun 1992 07:06:40

Quote:


>|> >
>|> >The solution is to go to either a smaller sail (so you are not overpowered)
>|> >or a smaller fin. The fin gives you lift but its lift component of
>|> >the force is being overcome by the opposite force vector from the sail.
>|>
>|> Sorry Nick but I have to disagree about the fin. I won't go into the technical
>|> specifics but it has been my experience that too small a fin (for the sail size)
>I agree with Felix -- if you are spinning out you want to go for either a bigger
>fin or a better fin.  I can't imagine a plausible explanation for why a smaller
>fin would prevent spinout.  Taken to the extreme, such an argument would say
>that you could eliminate spinout by going to no fin at all!  However, I have
>read the same smaller-fin advice in an article in windsurf magazine, and IMHO,
>the author did't know beans about spinout or what causes it.

>Ned

Well, to add my $0.02 to all of this, my experience is that a smaller
fin (and definately smoother fins) can delay spin out.  I think that
there is a plausible explanation too.  I think that many times spinout
is caused by ventallation, that is air is pulled down into the low
pressure lense on the weather side of the fin greatly reducing the
amount of lift produced by the fin.  So, going to a smaller fin should
reduce the amount of lift created by the fin and thus reduce the
probability of spin-out...  (ok, so I haven't had my coffee today, but
I have noticed that going to a smaller fin reduces spin-out).  THe
other advantage of going to a smaller fin is that you get less drag
and so you can go a lot faster.  Too, I suppose it might be possable
to get a fin to cavitate (though I've never seen this or heard of it),
if you got a very large fin moving very quickly and keept it very well
gated...

-tom.
--
===============================================================================

 
 
 

Spinouts?

Post by Kirk Lindstr » Sat, 06 Jun 1992 04:48:45

Quote:
>Joel started the mess... 8-)
>}>>
>}>>    Sherman Island, Sunday, May 31, 8'8" (265cm) board, on the verge
>}>>    of being overpowered with a 5.7 sail, 11.5 inch pointer fin, trying
>}>>    to go to windward pushing on the fin, weight forward in the harness
>}>>    when suddenly, without warning, I'm going sideways.  
>}>>
>}>>Any enlightenment would be appreciated.
>}>>
>}>>Ray Seiffert

>}>This can be and no doubt has been a FAQ.
>}>
>}>The solution is to go to either a smaller sail (so you are not overpowered)
>}>or a smaller fin. The fin gives you lift but its lift component of
>}>the force is being overcome by the opposite force vector from the sail.
>}
>}Sorry Nick but I have to disagree about the fin. I won't go into the technical
>}specifics but it has been my experience that too small a fin
>}(for the sail size) will increase the chances for spinouts.
>}
>}If the fin is too small the sails power will in effect cause you to put more
>}pressure on the fin (unless your technique is perfect). Small fins with big
>}sails cannot handle the load and will easily spinout.
>What I have found is a larger fin will help avoid spinouts in the case of
>}larger sails.
>>--

>Could it be you are both right?

>    As the sail size increases the fin size should increase.

>    As the board speed increases the fin size should decrease.

>joel clark

----------
You have to consider location (i.e. conditions) in this as well.  A 13" fin
is just about ideal for a 5.7 sail as long as it is in good condition.  Sailing
smaller fins is possible, but takes excellent technique to not spin-out.  
Sherman Island gets some swells and my guess it was 15-25 knot wind where a
good ebb will make starboard pointing difficult as you sail into the face of
the steep chop - often getting air.  A fin is only too large when it:
-causes the board to tail walk  
  or it
-causes you to go slower than someone else you want to pass.

The fin Felix mentions goes along way towards solving both of these
problems, but you still have to keep the fin in the water as well as
not overloading it when pointing.  This is where working on technique
is helpful.  I think my original reply is still the best way to go.

Kirk (my $0.03 worth) out

 
 
 

Spinouts?

Post by Kor Kil » Wed, 10 Jun 1992 05:48:53


Quote:


>>|> >
>>|> >The solution is to go to either a smaller sail (so you are not overpowered)
>>|> >or a smaller fin. The fin gives you lift but its lift component of
>>|> >the force is being overcome by the opposite force vector from the sail.
>>|>
>>|> Sorry Nick but I have to disagree about the fin. I won't go into the technical
>>|> specifics but it has been my experience that too small a fin (for the sail size)
>>I agree with Felix -- if you are spinning out you want to go for either a bigger
>>fin or a better fin.  I can't imagine a plausible explanation for why a smaller
>>fin would prevent spinout.  Taken to the extreme, such an argument would say
>>that you could eliminate spinout by going to no fin at all!  However, I have
>>read the same smaller-fin advice in an article in windsurf magazine, and IMHO,
>>the author did't know beans about spinout or what causes it.

>>Ned

> Well, to add my $0.02 to all of this, my experience is that a smaller
> fin (and definately smoother fins) can delay spin out.  I think that
> there is a plausible explanation too.  I think that many times spinout
> is caused by ventallation, that is air is pulled down into the low
> pressure lense on the weather side of the fin greatly reducing the
> amount of lift produced by the fin.  So, going to a smaller fin should
> reduce the amount of lift created by the fin and thus reduce the
> probability of spin-out...  (ok, so I haven't had my coffee today, but
> I have noticed that going to a smaller fin reduces spin-out).  THe
> other advantage of going to a smaller fin is that you get less drag
> and so you can go a lot faster...
> I have noticed that going to a smaller fin reduces spin-out).  

Should we say then, that if you're spinning out because your fin is too big
for the conditions, then the solution is to go to a smaller fin;  and when
you're spinning out because your fin is too small for the conditions, then
the solution is to go to a larger fin?  

And here's another aspect that I've noticed:  if you're in really gnarly
conditions with a small sail and the chop (and your fatigue) are keeping
you from putting your foot to the metal, you won't have enough speed to
generate enough lift for the small fin to do its job.  In other words, you
have to be going fast enough to make the small fin work.

Quote:
> ...Too, I suppose it might be possable
> to get a fin to cavitate (though I've never seen this or heard of it),
> if you got a very large fin moving very quickly and keept it very well
> gated...

I'm afraid I don't understand the last sentence.  Did you say what you meant
to say?  - Kor
--

Bailey/Howe Library
University of Vermont
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Spinouts?

Post by Jim Munro x24 » Wed, 10 Jun 1992 04:05:49

: To work windward, get the sail back (aft) as much as possible and
: keep the board flat (or slightly seemingly leeward).

: What this does is gets more board out of the water which makes
: you go faster while all the weight is on a smaller area of the
: board.  This keeps the fin in the water better.  I think a fin
: which is angled down and leeward (because the board has the
: windward rail down) spins out faster than a fin which is vertical.
: Sailing this way also allows the sailor to push with a more
: forward vector - not so much sideways pressure.

Well I guess I am not the only one who thinks moving the mast back is the
way to go upwind!

The argument for moving the mast forward so that you keep more rail in the
water is only for marginal or non-planing conditions. When you are fully
powered only a small part of the board is in the water. If the main
propulsive force is acting forward of the fin, it will tend to force
the board downwind. So for going upwing fast, move the mast back.

Whats wrong with this argument?

Jim Munro