I spent several years trying different hand planes. Sometimes I went longer but found that they puller really hard in big surf. I once asked Mark Cunningham about his favorite hand plane and he said small, light with concave is best. I agree. I make them with just enough surface area to lift the top third of your body out of the water on takeoff. Yet, they are small enough to hold on to when getting tossed around in the whitewash.
They are actually very tricky to make and the price has to reflect that.