I have used a similar fin called Stingray in two applications....Volvo 125 on a 21ft Bayliner and 6hp Johnson on a 11ft flatbottom. In both cases I liked the result. Faster planing and holding a plane at lower speed (nice in rough water). I'd recommend one if your power is on the low side for your boat, however if you have plenty of power it may hurt your top end and you don't really need it.