This is when the propeller works behind the ship because there is a wake we have already discussed. The speed of water that is falling on to the propeller will be less than the speed at which the ship was advancing. That is ok? So, that is one effect that we have - the effect of wake. Secondly, we have seen that the, when the propeller was not there, the resistance of the ship was equal to the tow rope resistance. We have defined the
resistance of a ship as the force required to pull the ship by means of a tow rope when the propeller is not there.