I changed the angle of the side fins so they dont point IN towards the nose but point OUT, splayed, so that the front of the fins point away from the stringer.
So what happened?
3 things,
1/. It seemed faster in a straight line,
2/. It had lowered resistance through a turn and it felt like soft grip and it was harder to make a defined turn.
Cutting back your inside fin is going to be angling towards your turn not your outside fin. The outside fin probably wont “touch” as much regardless of toe in or out if you are cutting back. Same for bottom turns I would imagine. Not sure what else to add really.
I tried this on a fish in the early 70’s. Did not stay with it very long…Maybe a couple DAYS, can not remember all the details but was not impressed. Good luck.
I changed the angle of the side fins so they dont point IN towards the nose but point OUT, splayed, so that the front of the fins point away from the stringer.
So what happened?
3 things,
1/. It seemed faster in a straight line,
2/. It had lowered resistance through a turn and it felt like soft grip and it was harder to make a defined turn.
3/. It hung naturally a lot higher in the wave.
And that was with about 6 degrees of toe-OUT.
Any theories as to why this is happening ?
Now Ive set it up with ~ 12 deg of Toe-OUT.
Surffoils.
Assuming a 4.5" base, that’s almost a half inch of toe-out at 6 degrees. Is that how much you went OUT? I’ve increased toe-IN and felt an appreciable amount of slowdown, like my board was plowing a little. It seems to me like too much either way would cause the same thing. Let 'er rip, and see how it goes! You never know until you try it, for sure!
i have try toe in to toe out max 1/2 " and now ended up with no toe run fins straight with 6 degree cant and uses all full foil fins it makes the board faster more predictable smoother turning but it is hard to get the fin company to sell you three center fins
Thanks, Mike, for your positive answer. I wanted to try this set-up on a proto that I made around last october but then I got stuck into that new work-shop thing and i haven’t been able to do much R&D. But I will, for sure, as soon as possible. And, yes, I was thinking about 4WFS for this project…
just think that any time you try to redirect water flow it create drag on the surfboard i work with Connelly water ski on fin design and fin placement and the thing that work best for water skis is a thin plate of aluminum or carbon which is too dangerous for surf boards and since a surfboard dose not travel as fast the fins don’t have to be so thin
Richard, I hear you. Of course, on my little sketch above, positions have been over-exagerated, just for ease of understanding. The more angle, the more drag, that’s for sure. Hence the need for variable angles and cant to play with and see what works and what doesn’t.
ACE,good to hear someone tried it before me, I agree its not initially impressive but Im going to stick with it to work out why.
MORGHEAD, front fins toe-in and rear fins toe-out ?, I’m going to try that arrangement and then try front ones out and rear fins in just to compare.
SURFTHIS, yes I thought Id try going for big angle deviations from the norm and then whittle the angles down to refine it. Ive tried quads with the rear fins 10 inches back/ 4 inches in from the front fins just to see what happened. The board had buckets of grip when on the rail but it felt like the 2 sets of fins were too distant to work in harmony and that they were fighting for control. The rear fins were really stiffening. It made me think that Bill Thrailkills ‘double single’ fin arrangement would be mighty tough.
My theory is that fins need to be close enough to work together (quad) or far enough apart so they can efficiently function seperately. (twin)
BENNY1, I tried the 12 deg toe-out board yesterday and it felt slowest in a straight line, the board had constant resistance and not just thru a turn. I think the fin itself wasnt happy with the 12 deg. Its just too much.
RICHARDL, I run my boards with 0 toe too and follow your idea of less drag, I use 2mm aluminium fins exclusively so I eliminate any foil drag too.
I believe that “any drag surface is a control surface” ( quote from someone here on Sways)
But controlling the water harnesses the energy we need. So you need to creat additional drag to produce speed above and beyond whats available to from the natural interaction of a no fin surfcraft on a wave and gravity etc, so Im testing a range of angles to see which degree of toe of combo will harness the waves energy best. I’d like to know a lot more about how water skis handle the high speeds
.
I think the quad combo of ‘front out and rear in’ like Balsa’s suggesting is tomorrows experiment for me.
I rode the quad with the front /toe in, back/toe out configuration and there seems to be a major difference in the feel due to a minor adjustment to the toe.
If I could compare it to something it would be the Attach, Decay,Sustain,Release analogy taken from digital music based ona window of time. Sounds have indivual patterns to their construction and its similar to the characteristics of fin performance. eg a plucked guitar string has a quick Attack as it reaches its max volume almost instantly but it has a long release as the note lingers for a long time.
As a fin example, consider the quick initial snap of a twin fin, thatd be considered its Attack characteristic and yet the twin drops power just as quickly in the last phase of a turn, that’d be its Release. In comparison a big single fin has a slower Attack phase but a long Release phase because it holds the water pressure longer.
I play a bit of music and when I try to qualify how a fin feels it becomes as subjective as music and therefore they have some similarities.
Its a bit of a different theory but the musicians should already understand the connection.
In regard to toe in and out, toe out has very low Attack, even Sustain and slow Release.
I plan to try a reverse arrangement with the quad and test it after I get a better feel for the current setup.
