Question on Fin Position (TrimBox)

Question on Fin Position (TrimBox)

Post by Jon Loome » Tue, 17 Oct 2000 04:00:00


Hi,

I just bought a used BIC Veloce 278. It came with a 31cm pointer fin. The
board has a trim box, which allows the fin to be placed in several positions
in the fin box, by sliding some little spacers about.

This is the first board Ive used with this type of box. Can someone with
more experience tell me how I should adjust my fin position. I guess it
relates to sail size, postion of base in mast track, sailing conditions and
all the usual other parameters. But in a nutshell, where should my fin be?

Thanks

Jon Loomes

 
 
 

Question on Fin Position (TrimBox)

Post by WARDO » Tue, 17 Oct 2000 04:00:00

Hi Jon,
"Proper" fin placement (tweaking) FOR THE CONDITIONS (wind & H20) you
are sailing in is dictated by many parameters as you have noted and many
more including board rail design (tuck, hard/soft), footstrap placement,
fin design (rake and chord length),foil, material,flex and size, how you
have your rig tuned, your body leverage characteristics (height, harness
type...etc) and sailing style (do you like to sail overpowered) and
ability, plus others...so you will have to do trial and error like you
suspected with the first best guesstimate being the center position.
Look at things like your jibing radius, ability go to weather,
are you spinning out on a reach or landing jumps....if you like to go
fast in a straight line move it back, if you want to turn better move
the fin forward. Don't make several adjustments at once eg..moving mast
track forward, flattening sail, tightening footstraps and moving fin
UNTIL you know the effects of each move personally. That just means
tuning until you get dialed and T.O.W. (time on the water). Poorly
designed equipment (especially fins and sails) will limit the amount of
tuning that can be done. A "good" aftermarket fin is the most cost
effective way to improve your kit. We work directly with True Ames here
in Santa Barbara, Calif.
to ensure hand finished quality and an extremely close tolerance fit
regardless of fin box type and carry the complete line of True Ames fins
and a line of wave and B&J fins that I have designed and are built by
True Ames. Have fun tweaking!
http://www.surfingsports.com/trueames.asp#

WARDOG
http://www.surfingsports.com

Quote:

> Hi,

> I just bought a used BIC Veloce 278. It came with a 31cm pointer fin. The
> board has a trim box, which allows the fin to be placed in several positions
> in the fin box, by sliding some little spacers about.

> This is the first board Ive used with this type of box. Can someone with
> more experience tell me how I should adjust my fin position. I guess it
> relates to sail size, postion of base in mast track, sailing conditions and
> all the usual other parameters. But in a nutshell, where should my fin be?

> Thanks

> Jon Loomes


 
 
 

Question on Fin Position (TrimBox)

Post by Nazk » Wed, 18 Oct 2000 04:00:00

hi,
In fact it's very easy. There are several positions in the fin box because of
several footstraps positions.
The fore part of the fin must be straight up the back of the rear footstrap.
So if you are "novice" the footstraps must be in a forward position as the fin.
If you are expert it's the opposite.Easy!!

Christophe
France (sorry for my poor english)

Jon Loomes a crit :

Quote:
> Hi,

> I just bought a used BIC Veloce 278. It came with a 31cm pointer fin. The
> board has a trim box, which allows the fin to be placed in several positions
> in the fin box, by sliding some little spacers about.

> This is the first board Ive used with this type of box. Can someone with
> more experience tell me how I should adjust my fin position. I guess it
> relates to sail size, postion of base in mast track, sailing conditions and
> all the usual other parameters. But in a nutshell, where should my fin be?

> Thanks

> Jon Loomes


 
 
 

Question on Fin Position (TrimBox)

Post by Roger Jacks » Wed, 18 Oct 2000 04:00:00

Hi  Christophe,

Quote:
> In fact it's very easy. There are several positions in the fin box
> because of several footstraps positions.

Ummmmmm.... I think at one time this was the accepted way to look
at this, but with wider boards, better, faster rockerlines, and
improved stability in sails, it's no longer this simple.

Quote:
> The fore part of the fin must be straight up the back of the rear
> footstrap.

Not anymore. One the wide race boards, and AVS boards, I often find
my back foot to be nearly over the center of the fin.
On 90-120 liter free ride boards, it still may be true to some degree,
but you will give up both performance (speed) and maneuverability
if you move the footstraps every time you move the fin.
Moving the fin forward (even a little under your foot) will loosen
the board up and allow more slashy turning, and a bit better in
the jibes.
Moving the fin back can be used to prevent spinout, increase overall
speed potential, and improve upwind sailing.
This contradicts what someone else has said, but I've always found
the the further away from the fin you put the mast foot, the better
the upwind performance (except in the case of the new very wide
boards, huge (50 cm +) fins, and shorter planing flats.
You cannot afford to lower the nose and push the rocker into the
water just to improve upwind sailing performance. You loose too much
speed overall, and with the proper fin and technique, you can go
extremely high with the fin and footstraps all the way back and the
mast foot positioned to keep the board at the best planing attitiude
for overall speed.

Quote:
> So if you are "novice" the footstraps must be in a forward position
>as the fin.

I agree that for novices the footstraps need to be forward, but not
necessarily the fin also. This will make the board more twitchy
and less easy to maintian directional control.

Quote:
> If you are expert it's the opposite.

Gotta disagree here. Most experts have a definite relationship
that they want between the fin, footstraps, and mast foot.
They measure this, and have been known to have footstrap plugs
added, mast boxes moved, etc to ensure that they get the set up
that feels right for them.
Also, expert sailors will move the fin a little to compensate for
water conditions, the type of sailing they are doing (wave/B&J/slalom/
racing, the fin style they are using, etc, but they rarely move the
footstraps once they get them where the board works best for them.

Easy!!
Well, not quite so easy, but you make a good point about having the
leading edge of the fin "project" up to the back of the rear footstrap.
In most cases, when you aren't sure what the relatiionship should be,
this is excellent advice on a good starting point.
But it differs with different boards, fins, sea conditions, sail sizes,
so experimentation is also good.

Quote:

> Christophe
> France (sorry for my poor english)

> Jon Loomes a crit :

> > Hi,

> > I just bought a used BIC Veloce 278. It came with a 31cm pointer
fin. The
> > board has a trim box, which allows the fin to be placed in several
positions
> > in the fin box, by sliding some little spacers about.

> > This is the first board Ive used with this type of box. Can someone
with
> > more experience tell me how I should adjust my fin position. I
guess it
> > relates to sail size, postion of base in mast track, sailing
conditions and
> > all the usual other parameters. But in a nutshell, where should my
fin be?

> > Thanks

> > Jon Loomes

--
sailquik US 7011
Sailworks/Starboard

Sent via Deja.com http://www.deja.com/
Before you buy.

 
 
 

Question on Fin Position (TrimBox)

Post by Nazk » Thu, 19 Oct 2000 04:00:00

Quote:

> Easy!!
> Well, not quite so easy, but you make a good point about having the
> leading edge of the fin "project" up to the back of the rear footstrap.
> In most cases, when you aren't sure what the relatiionship should be,
> this is excellent advice on a good starting point.
> But it differs with different boards, fins, sea conditions, sail sizes,
> so experimentation is also good.

I agree with you : it depend on the board (shape). But my advices are
enough good for BIC freeride shape and BIC users. No?. It's a good begin.

I don't use wide race board but I noticed the back foot was over the center
of the fin.
Sure I prefere a US box fin on wave boards in order to move the fin
according to the sea and wind conditions. For exemple, in offshore
conditions I move the fin forward for better surfing  and in onshore
conditions I move it back. But it depends on the shape of the board......as
you feel.

Christophe

 
 
 

Question on Fin Position (TrimBox)

Post by Roger Jacks » Thu, 19 Oct 2000 04:00:00

Hi Nazka,

Quote:
> I agree with you : it depend on the board (shape). But my advices are
> enough good for BIC freeride shape and BIC users. No?. It's a good
> begin.

Yes, your advice is good for anyone on any board with fore/aft fin
adjustability, as a starting point.
I was only suggesting that people sart out with your suggestion, and
then experiment a little bet so see what the affect is on their board
with their rig and skills set.

Quote:
> I don't use wide race board but I noticed the back foot was over the
> center of the fin.

It's quite different at first, but easy to adjust to. But it takes the
big fins to make it work.

Quote:
> Sure I prefere a US box fin on wave boards in order to move the fin
> according to the sea and wind conditions. For exemple, in offshore
> conditions I move the fin forward for better surfing  and in onshore
> conditions I move it back. But it depends on the shape of the
> board......as you feel.

Yep, that's exactly right. But many, who don't have the skills that
you and I have, will read your post, and begin moving the footstraps
to match the fin, or vice versa.
Could be a little confusing as the board would not act the same.
Rgds,
    Roger

--
sailquik US 7011
Sailworks/Starboard

Sent via Deja.com http://www.deja.com/
Before you buy.