Curious what the brains trusts take is on US boxes.

they seem to come in varying depths. Windsurf fins appear to be slightly deeper than surfboard fins. was hoping to install futures longboard boxes in a windsurfer but not certain fins will fit. One I've tested on the bench won't fit..

All us box and slot is 1" deep fins

All longboard boxes I have seen are the same but wayyyy weaker

Yeah that's what I thought but have a few here and they seem to have different depths.
chinook being deepest and futures one shot longboard shallow. I could be loosing my mind too. Lol

Variance doesn't surprise me but the strength would worry me
Hard to explain but one sort of longboard box is laterally very weak

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Gestalt said..
Yeah that's what I thought but have a few here and they seem to have different depths.
chinook being deepest and futures one shot longboard shallow. I could be loosing my mind too. Lol

Not only the depths but the width are different. Chinook & Cobra are on the same standard since the last 30years. The width is nominally 9.1-9.2mm & the depth 28-29mm. You can shim a surf fin to fit in the US box but US box Windsurf fins will not usually fit well in the Surf box.

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gorgesailor said..

Gestalt said..
Yeah that's what I thought but have a few here and they seem to have different depths.
chinook being deepest and futures one shot longboard shallow. I could be loosing my mind too. Lol

Not only the depths but the width are different. Chinook & Cobra are on the same standard since the last 30years. The width is nominally 9.1-9.2mm & the depth 28-29mm. You can shim a surf fin to fit in the US box but US box Windsurf fins will not usually fit well in the Surf box.

Yeah that's what I've noticed. I think the windsurf fin base is deeper too.

Measured two chinook us boxes
one with post, one without

both 26.5mm...

two longboard boxes
one 26.5 and one 28mm
they're designed to be sanded down a bit to account for the massive rocker in a longboard. So really no difference and I am sure all the fins I've seen are a 1" base

anyway I'd not use longboard boxes, they are pissweak and I see them fail all the time with very little loading