The numbering on a Bob's Jack plate is in inches of plate going up and down. So 3 3/4 is 3/4 inch higher than 3 on the gauge. I just retuned home from Florida and have not been able to measure p to p yet. With the manual plate It ran best at 2.75 to 2.5 inches p to p. I tried as high as 2 inches and also the boat would chime walk at 3.25 and lower. Dealer sent me out at 4 inches p to p and the boat was a real handful. Still very happy with hydro plate!
Bill