The wind that blew the sand could have drifted the ship at a rate too fast for the rudder and engine to overcome in such a narrow waterway.
Merchant ships are universally single screw, so differential engine power can't be used to increase the rate of turn like you can with twin screw vessels (most combatant warships)
They also have dismal acceleration and reversing ability compared to combatant warships.
Bow thrusters (if this ship even had them) can tighten the turn somewhat but don't do anything for headway.
GPS accuracy has fuck all to do with how the ship responds to wind and current.
What's your bridge watchkeeping experience, again?