Pilot Robert was afraid about the resultant movement due to ...

Pilot Robert was afraid about the resultant movement due to sinkage and to bow-up rotation of a container ship with Blockage Coefficient = 0,83, he knows that in this case the trim can be negative (that is, bow down) owing to lowspeed operation in shallow water.
Robert, following the “Principles of Naval Architecture”, was introduced to the results and theoretical studies of Professor Tuck. From his studies, Robert, achieved a value to describe the hydraulic force (squat´s force) acting on the ship proceeding in relatively narrow canal.
What is the alternative that is not important in a Tuck’s squat calculation, used by Robert?