Tri Design

dorjeseahorse · Post by **dorjeseahorse** » Mon Nov 28, 2005 5:42 pm

fin size may come into play here and style...more upright v low

too far foward might mean you spin on the spot or nose dive in the attempt to gain control

but then this just hypothetical

ScottMac · Post by **ScottMac** » Mon Nov 28, 2005 6:19 pm

ross · Post by **ross** » Tue Nov 29, 2005 12:08 am

and i thought all thrusters were aussie

thanks Simon Anderson

scoop · Post by **scoop** » Tue Nov 29, 2005 2:17 am

Beeline
RE ... The board you are talking about
The centre fin will move to the extreme 2"( 50mm ) forward of or back from the outer fins (set in fin box's for different possibilities)
This was one of Bruce's first tri fin boards (Simon Anderson design)
I doubt if it will ever be riden again as I want it for art purposes (wall hanging)
He would be best to describe differing attributes though I can say his recent designs (trifin) have the centre fin positioned about 8" (200mm) behind the leading edge of the side fins
I am sure there is a reason for both designs but I buy boards ... don't design ... I just leave it to the x sperts

Tony

surfhorn · Post by **surfhorn** » Tue Nov 29, 2005 8:32 am

My experience with tri fins started back in 1972.......12" center flex fin with 2, 3" rail fins. You rode the board from the center as compared to a twin/Fish which one rode on the tail.

We kept experimenting with length, width, etc. then went with the Thruster design once that came along. For tail riders, the three fins clustered on the tail worked really well but for someone llike myself, who rode from a more forward position, it wasn't the answer I was looking for.

I wanted to be able to really push energy into the two side fins so I took the current board I was riding and stripped the wax off the deck and measured my knee wells, looking for the exact position where my ankles struck the deck. I used that location to position my 2 side fins, leaving the center fin about a fin base & 1/2 up from the swallow tail. The 2 fins ended up around 21"+ up from end of board. (all three fins were the same depth).

That was the secret to making a highly functional craft for whatever I surfed in the Monterey Bay area. My 5'8" double wing swallow 3 fin (circa late 1990's) was one of the best boards I've ever ridden.

W.G. Facenda · Post by **W.G. Facenda** » Tue Nov 29, 2005 3:20 pm

The early 3 fin Bonzer with double concaves was in 1970.I would say the Simmons was an early twin with concave in 1957.

Shelfbreak · Post by **Shelfbreak** » Tue Nov 29, 2005 11:01 pm

I'd suggest (2c worth) that the middle board in Scoop's fine wall mounted display is best considered as a single fin slab augmented with two flyer fins. The middle large flex fin remains a key feature. I think there is a design jump to the current forward placed tri fin designs where the fins are of similar dimensions.

I recall riding a friend's board like Scoops but with the flyer fins set forward of the large centre fin. Fun to ride and an improvement (for me) over the standard slab flextail I had then - but I certainly couldn’t turn them as proficiently as a contemporary Flashpoint. However it’s well worth watching how well PC rode his slab in that Pub Squash commercial featured in Sparrow’s ‘Now and Then’ DVD.

scoop · Post by **scoop** » Wed Nov 30, 2005 2:02 am

Guys
look at the pic
[/img] album_showpage.php?pic_id=5492 [img]
Maybe someone can explain the differing design and fin placement reasons

Tony
[/img]

Beeline2.0 · Post by **Beeline2.0** » Wed Nov 30, 2005 7:14 pm

red · Post by **red** » Wed Nov 30, 2005 7:27 pm

all surf boards are Polynesian

surfhorn · Post by **surfhorn** » Wed Nov 30, 2005 7:52 pm

Red- Touche!

ross · Post by **ross** » Thu Dec 01, 2005 1:01 am

hey fellas,i didnt mean to say that Simon Anderson invented them

.
as we all know he just made em work

and as far as i know they're still going alright.didn't Slater win 3 or 4 on Simons boards this year?

red · Post by **red** » Sun Dec 11, 2005 9:32 pm

I've been considering for some time now that the stabilised twin is possibly best for a kneeboard. Fastest and free-est. Used by the best nowadays and looked great in old footage. We may have over refined in our quest for the kneeboard thruster concept.

Lots of the thoughts above contribute but especially old footage and watching the Simpsons. I especially like HWs idea of getting less drive out of a wide configuration. I guess you can go big triangle (rail fins to trailer) with a small trailer fin or smaller triangle with bigger centre fins to achieve similar overall effects (they all just slide out on me - but that's just because I push too hard with my feet).