Does an inch in cord length matter much in fin sizing? I'm thinking about going from a 12.5" to a 13.5" with slight foil or shape changes.

It's more how you use your inches, rather than how many inches you have.

huge, think fin inch like sail square metre.

then add cord variables.

Kinda crazy that fin size is measured in inches (or even centimetres if you're really progressive!)... Imagine if sails were refererred to by how long the mast was rather than surface area.

I've always wondered about that, I have noticed the odd fin that also quotes area.
But that is far from the whole story, there's also rake angle and chord to thickness ratio.

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Ben Severne said...

Kinda crazy that fin size is measured in inches (or even centimetres if you're really progressive!)... Imagine if sails were refererred to by how long the mast was rather than surface area.

Maybe you can start a new trend by putting fin area in cm2 on the f o fins

My new FO fin has cm2 on it...

(or are you being sarcastic?)

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waterlog said...

Does an inch in cord length matter much in fin sizing? I'm thinking about going from a 12.5" to a 13.5" with slight foil or shape changes.

Yes...assuming the fins are similar (if not identical) going from 12.5 to 13.5" is about the same as adding half a meter of sail.

Aspect ratio also plays a part. My 38cm Drake fin has more area than my 40cm Curtis fin.

Rake is also important, particularly with weed fins. My FO 32cm weed fin has a very similar area to the 40cm Curtis.