Multi fins are everywhere and I was interested if conversion were feasible, so I decided to convert my Starboard Evo 70 to be a multi fin board. The result turned out great, so I'm now offering a service of installing 4WFS boxes on your board.
I started to research fin sysyems and came across the four way fins system (4WFS). I was struck by the ease of adjustment available from the system, so decided to give it a try. I installed the fins so I could run the board as a quad, thruster or single. This is the result:
The fins I had available are:
17.5 from a mistral twinser
2 x 14.5cm side fins (4wfs)
2 x 11cm side fins (4wfs)
2 x 11cm center fins (4wfs)
My observation after using for a week on Tiree:
Multi fins turn better.
Quad more draggy than thruster or single.
Quad more secure when stacked.
I think with smaller fins, drag from the quad could be reduced, but still have sufficent area.
The toe in angle is critical. I installed the boxes with no toe, they are adjustable 2.5 deg both directions.
Front fins toed out 2.5 deg - the board wouldn't plane.
front fins toed in 2.5 deg - front fins ventilated but board sailed ok. More draggy, no turning benefit.
Straight performed best. Note this is for the evo that is a double concave shape in the rear, a board with V may require more toe. Next time i'm sailing I plan trying both front and rear fins toed in 1 degree.
Quad fins feel a little more draggy
4 x 11cm fins fine for sails smaller than 5.3m
2 x 11 rear and 2 x 14.5cm fins better for sails up to 5.6m or when under powered on 5.3
Very dependable when stacked, but still turned very well. Preference when well powered. Smaller fins should be tried next.
Performed very well, good for more marginal conditions. Very adjustable.
Setup with 2 x 11cm front 17.5 rear
rear fin position had massive effect, could transform board from exceptionally loose, almost uncontrollable to very secure.
Felt more locked in like a freeride board after using multi fins, evon on an EVO!
Want Multi Fins on your board?
Prices for a conversion are available here. Get in contact to discuss your requirements as there are loads of options.
I've used a gopro to produce a time lapse video of two fin boxes being installed on a RRD cult wave.