FinSciences 4.8″ fin

FinSciences 4.8" fin 1
(1 customer review)



Total area: 10.14 in²
Template/planform area: 9.75 in²
Finlets area alone: 0.9 in²
Height/depth: 4.8 in
Rake/sweepback: 22°
Foil section: symmetrical (double)
Anti-cavitation trailing edge
Stiffness: semi-flex or stiff
Colors: gloss black, blue, matte black
Fits FCS (and Futures with adapter)

SKU: Four-eight-fin Category:

FinSciences 4.8′ shortboard fin is 4.8 inches tall, and has 10.14 square inches in area.  It’s available in stiff (matte black) or semi-flex (in glossy black and translucent blue).  FinSciences 4.8′ shortboard fin can be used as part of a thruster setup, a quad setup, and as sidebites in a 2 + 1 setup.

Check out our fin-size calculator >>

These fins are smaller than what you’re used to–but that’s the point.  Compared with typical fins, we’ve chopped off about 30 percent of the least efficient area, then added back a bit as winglets–or finlets–so that overall our fins are smaller, yet outperform other fins.  This concept works–it’s why airplanes, race cars and boats use winglets, finlets, and endplates.

FCS-to-Futures fin adapter

FCS-to-Futures fin adapter

Adapter: FCS-to-Futures Adapter

Have a Futures setup? No problem! Get an adapter here:


  • Total area: 10.14 sq. inches
  • Height/depth: 4.8 inches
  • Rake/sweepback: 22 degrees
  • Foil section: symmetrical (double)
  • Winglets area alone: 0.9 sq. inches
  • Planform area alone: 9.75 sq. inches
  • Fits FCS

Sizing of FSI Fins Compared to Typical Fins

Our fins have a lot of power–hold and drive. Because they have a lot of power, your right-sized FSI fin will have an area smaller than what you’re used to.  And because they are smaller, they have less drag.  This means that you can accelerate more quickly, paddle more easily, or surf longer.

Basically we take a typical fin, chop off about 30 percent of its area, then replace about 5 percent in a more modern configuration.  This removal of surface area, and its skin-friction drag, is one of the key concepts behind our fins.  Our fins resemble modern-day airplane wings and boat keels–because the science justifies it.  Our fins are unlike dolphin fins that have dominated the market for the last 50 years.
Winglets are solid science and they work.

Winglets and other features we use make these fins about 20 to 30 percent more efficient than larger, older styles, so you need to downsize by about 20 to 30 percent as compared to the fin or set of fins you typically use.  Read more about lift, drag, hold and drive.

Example: If you typically surf a set of mediums in a thruster setup, fins that are usually about 14.5 sq. inches each, you are surfing 43.5 sq. inches of fin. Try our smalls. Our new small is 10.14 sq. inches, and a set of three is 30.42 square inches, a 30 percent reduction in fin surface area, and a 30 percent reduction in skin-friction drag.
Another example: If your longboard or SUP board has a center fin and two sidebites, calculate the area of your current fins, then try downsizing–try pulling off the sidebites and going with a single Wavegrinder 2 longboard-SUP fin. You will dramatically decrease the area of the fin, yet still get good hold and drive because of the winglets and other features of our fins.

FSI Fins, Areas in Sets

Because FSI’s current fins are symmetric, you can either get a set of the same fins, or mix smaller and larger fins to get the ride you want.

Check out our fin-size calculator >>

Additional information

Weight2.2 oz
Dimensions5 × 3 × 1 in
Stiffness & Color:

Semi-flex gloss black, Stiff matte black

1 review for FinSciences 4.8″ fin

  1. FinSciences 4.8" fin 6


    Review for FinSciences 4.8 inch fin for shortboards, thrusters, sidebites, and quad setups, fits FCS1
    ★ ★ ★ ★ ★

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