All things being equal - The question I have is on a thruster, but any knowledge you have would be appreciated.
What difference would it make to move the side fins @.5" towards the rails/.5-.75" in from the rails. If you know, share about even more extreme placements in relationship to the rail. And/or if you have experience on different board
For the sake of numberphiles, 7’7" round pin, 22" wide, 12" nose and tail, 2.75" thick, 6"nose rocker, 4" tail rocker, single to double flat panel V out of side fins. Center fin 4" up, side fins 12" up 4-5 degrees cant - Toe’d off nose (which I know will change, so also consider the 1.25" from rail - 4.5" line parallel to stringer, off set .25") If you want more info - rider @ 190 lbs., competent surfer up 2+ oh, beach, reef, point breaks.
Just been thinking about the next project - and side fin possibilities/limitations by boxes.
Fins further outboard than 1.125" from the rail get real pivot-y/draggy (in turns). The water needs to re-attach behind the fin before it exits over the rail. If not, you lose the interactions with the bottom of the board, and a lot of re-direction capability. Moving inboard will weaken the fin but the interaction will stay basically the same, and it is much less sensitive than moving it outboard.
These measures are taken from the rear base of the fin to the vertical projection of the rail.
I’m thinking of putting some RedX boxes in side by side on the rails - with the inside one’s a bit up from the tail, @.25-.5", and more cant on them too, “outer” @ flat=4 degrees built in fin, and 4-6 degrees for “inner” ones… For a set up that would be better for smaller/mushier waves.
Made a board with similar fin set up to my “inner” suggestion, and it went great in “lesser” waves, but when it got thicker and hollower, the 8-10degrees (I don’t remember, will check) of cant made the thing climbed the pocket too much… Ha! So, I was wondering what people thought about a fin being about 2" in from the rail… But, I was thinking of using some big side fins too.
Have any feed back on your surf trux in a 4xquad type set up?
like tail area (in your case you have a narrow tail area), fin area and where you put your back foot
in a 7 7 you dont surf with the back foot in the very tail, so in my opinion, not too much significance moving 1/8 or so to the rail (due to the foot and the related maneuverability)