A slightly bigger fin will improve the zero speed stabilisation, which is recommended if the vessel has a top speed below 35 knots.
The 0.60-0.80m2 fins are designed to suit our fast SU-553 electric servo unit. The SU-563 servo is developed for the larger 1.00m2, 1.30m2 and 1.50m2 fins.
The chart below gives a general picture of recommended fin sizes. Certain boat types may require other solutions. Please contact your nearest Humphree dealer for advice.