I have a 70 cm fin and I was wondering what would be the smallest fin that would be suitable to use with a 7.5m V6?

I would be hoping not to sacrifice too much early planing

Thanks

on my 93 cm wide Free Formula I use a 66 cm fin with a 10-oh and
55 cm fin with 8.x

used to use 53 cm fin on my big freeride with the 10-oh and 48 cm with the 8.x

so the ratio is similiar for that drop in size and is close to the drop in sail size 8/10

and so perhaps 7.5/10*70 is a round ball park number - 53 cm about

Last time I had my formula out I used a Deb Formula fin cut down to 50cm and it was great. It would be useless for racing but for lightwind freeride it was sweet. Used it with a 9.6m