View previous topic :: View next topic |
Author |
Message |
rtz
Joined: 31 Oct 2010 Posts: 296 Location: Oklahoma City
|
Posted: Thu Dec 10, 2020 10:40 pm Post subject: Fin sizing |
|
|
I can't find it now; it seems there was either a measurement or simple formula for determining fin size or a starting point for a board. Measure from the back of the board up to some point or divide that number or something?
Anyone remember something like that? |
|
Back to top |
|
|
swchandler
Joined: 08 Nov 1993 Posts: 10588
|
Posted: Fri Dec 11, 2020 2:58 am Post subject: |
|
|
There is a relationship between the width of the board one foot off the tail and fin size. Of course, a lot has to do with the size of the sails you want to use.
In my view, lighter winds favor larger fin sizes. With the right flex at the tip, a larger fin can work to your favor. |
|
Back to top |
|
|
joethewindsufa
Joined: 10 Oct 2010 Posts: 1190 Location: Montréal
|
Posted: Fri Dec 11, 2020 6:46 am Post subject: |
|
|
you measure the width of the board 12"/30 cm from the tail
this is called the OFO or OneFootOff
and is the MAX length of the fin to put on the board
as discussed, there is SO much more to fins than OFO and length !!
{chord,flex, thickness, etc}
a good board/sail/fin combo is something to remember !!
http://joewindsurfer.blogspot.ca/2012/03/fins.html |
|
Back to top |
|
|
rswabsin
Joined: 14 May 2000 Posts: 444 Location: New Jersey
|
|
Back to top |
|
|
techno900
Joined: 28 Mar 2001 Posts: 4161
|
Posted: Fri Dec 11, 2020 9:26 am Post subject: |
|
|
There are a ton of variables that impact a fin choice. While just considering sailing out and back on flat or choppy water, the most critical is board speed.
If you are slogging or just slow planing, a small fin can be a problem because there isn't enough lateral resistance to keep the board from sliding sideways. A big fin at speed can be a problem because there will be too much lift and the board can flip as the fin tries to fly to the surface. This is where board width come in. A wide board is less likely to flip with a big fin while a narrow board is more likely to flip with a large fin.
And as mentioned, body weight is important. Take the same board, same sail and same speed. Sailor A at 150 lbs. needs a fin 30cm in length, while Sailor B at 200 lbs. need a fin 35-40cm in length. The extra weight helps balance the forces trying to flip the board. |
|
Back to top |
|
|
manuel
Joined: 08 Oct 2007 Posts: 1158
|
Posted: Fri Dec 11, 2020 2:56 pm Post subject: |
|
|
Youll need to account for volume too.
I'm using a 56cm wide board with a 19, and 54.5cm with... 23 and 60.5cm with?... 21 !!!
So it depends _________________ *NEW* - Manu's Windsurfing Blog, The STORE! |
|
Back to top |
|
|
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You can attach files in this forum You can download files in this forum
|
|
|