That is a good clip in a cuddy. You know me, I like it
I followed a Canyon Bay boat down the Homasassa River last weekend. Speed limit of 25 mph. Most boats do 30 on plane pretty easily. Not the Canyon Bay. 19.5 MPH. With no tabs I could plane and hang at that low a speed. He was tab down and easing along with a new E-tec. They gotta be torque monsters.. My boat is right on the edge of falling off plane at 19 so that is where the tabs come in handy. Tabs in and I can plane at 14 to 15 mph. Just messing around. The 250 isn't as happy there as it is at 3500 to 4000 RPM. Fuel mileage is darn good at the lower speeds.
That motor of yours has moxy but the cuddy isn't going to fly as high as the center console. 50 is moving in a boat and as has been mentioned, add a little wind and that speed is useless.. Mainly that is why I stick to the 21P prop. The Merc will turn it more efficiently and definitely does better at a slow cruise, like over big waves where you have to slow to that 10 to 15 mph crawl... The big props really drag the rpm down when climbing up the face of a wave at low rpm. Even trolling with them is a PITA so I like the small prop for everyday adventures... Top end is something I chased and have now ceased to engage in altogether. Bigshrimping has it right... How slow can you go.. on plane and efficiently as possible.