I have been experimenting with running the Spitfire X7 prop shallower than anyone else I have read about. I am experimenting with prop shaft to base of keel measurement of 3.5 inches on my Ranger RT188 and standard gear case 2016 Mercury 115hp 4 stroke. The pictures below show this height and shows how I am measuring. I have been unable to fully open up and trim out due to exceeding RPM top end. So I picked up a 21 pitch X7 and finally had the opportunity to test it today. I shot a cell phone video of the prop at full throttle and trim. The results are mixed. The 21 pitch held RPM down even overtrimmed. It was running 5900 in the video. Holeshot was acceptable and steering control was great. But the prop is just not super efficient at this depth on a mod-V hull. I believe without the lift of a pad, the friction of the hull results in prop slip numbers on the high side. Getting more foot out of the water greatly improves handling, but the trade off is higher slip. In the video the boat is running 46.2 MPH at 5900 RPM for a slip of 19%. I can drop the rooster tail and loose 100 RPM and pick up a bit of speed to 46.8 MPH for a slip of 16%. I can run deeper with less slip, but handling is a bit squirrelly or I can run shallow with zero handling issues but less efficiency. Other details, the speed is GPS and the RPM is from Smartcraft. Running alone, 3/4 tank fuel, full gear load. Trimmed that high water pressure is barely acceptable at 12 PSI.