Marine ship's slip
A simple program which assist you to calculate the slip of the ship.
The user Insert the pitch of propeller in meters the M/E revolution on watch (as per example for 24 hours) the ship miles (distance of the ship).
The output is the distance of Main engine (engine miles) and the Slip of the vessel.
Ship slip is the difference between the speed of the Engine and the actual observed speed of the ship.
The difference between the theoretical and the actual distance traveled by the propeller in each rotation and therefore the difference of theoretical from the actual speed is called slip.
When the user add the passing time (noon to noon as an example is 24, if we have one hour advance is 23, if we have one hour retard is 25) the output is the engine speed the ship's speed and the Main engine revolution per minute [rpm].

It is obvious that in every rotation of the propeller the distance the boat covers is less than the one the nominal pitch of the propeller defines.
Propeller slip is affected:
by factors related to the engine, the boat and the boat set-up: the type of the hull and its condition, the weight and the aerodynamic design of the boat, the design of the engine’s lower unit, the mounting height of the engine, the loads as well as the design of the propeller itself.
Large diameter propellers have less slip, just like propellers with great amount of cup, which improves their grip on the water and therefore the slip is reduced.
by external factors such as sea state, sea currents or the intensity of the wind.

DISCLAIMER
This application you use with your own responsibility and knowledge, any advice, comment or correction always is welcome. Thank you!