What do the two numbers on a boat prop mean?

-The numbers are the prop diameter and then the Pitch angle. The last number means how much forward movement in a full 360 degree rotation of the prop. It doesn't actually mean that's the full amount of forward movement you'll get.diameter of the prop and the pitch (angle) of the individual blades . You will also get into "cup"...Double cup/triple cup, this is like a little flip up at the back edge of the blade that gives a little extra "kick" as the prop turns