From a very wide 5.45m with a merc 75 four stroke we get 30 knots 4 up with a 17" it came with a chewed up 15" but it was over reving.
Also changed the fuel pumps and fuel system from the tank to the pumps, cleaned and balanced the 4 carbs.
We have antifoul that will come off one day when I feel like it. But first I'm going to remove the Dolphins on the leg as they seem to do more harm than good.
A 30 knot 4 seater is perfect for us even though I could go up to a 115hp, however if I really wanted some more power I could change the carbs as that's the only difference between the 75 and 90? But the fuel consumption is excellent with the 75, possibly the most fuel efficient boat I've owned