Bonzer Fins
Channeled speed.
How bonzer fins work
Bonzer fins are part of a system — they work with concave channels molded into the bottom of the board. The parallel double concave channels direct water flow through the tail "slingshot-like," reducing energy loss and propelling the board during and after turns. As one Swaylocks rider described: "Bonzers definitely give extra speed from a bottom turn and maintain it, so that I am now linking up turns much better."
A bonzer typically runs 3 or 5 fins: a center fin plus two or four angled runners (~2.75" tall with ~9.5" bases) that sit inside the channels. The runners dip in and out of the water during rail-to-rail transitions, limiting turbulence while providing edge control. The 5-fin bonzer, introduced in 1982, splits each runner into two smaller elliptical fins separated by a "flute" — another Campbell innovation.
You can't just put bonzer fins on any board — the channels and fin placement are designed together. But when it works, riders describe a "fifth gear" effect — sudden acceleration when pushing the board hard. One Swaylocks veteran put it simply: "imagine that single fin on steroids."
The designers
Started surfing in 1965, began shaping as teenagers. In 1970 they created the bonzer — "a quantum leap in possibilities" — designed to hold in the steep, hollow waves at Silver Strand and Point Mugu. Their father contributed to the design process. By 1972 the design was licensed to Bing Surfboards. In 1982 they introduced the 5-fin bonzer, splitting each runner into smaller elliptical fins — another tremendous shift.
Still not sure?
We carry the full bonzer fins selection at 4051 Judah St in the Outer Sunset. Bring your board.
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