Multi Fin Conversion using 4WFS

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:

• 24cm mcf
• 21cm mcf
• 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:

General: 

• 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 setup:

• 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.

Tri Setup

• 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.

Single fin

• Felt more locked in like a freeride board after using multi fins, evon on an EVO!