OMC International is the sole provider of Dynamic Underkeel Clearance (DUKC®) systems. OMC’s systems predict and manage underkeel clearance for vessels travelling along depth restricted waterways. These systems have now advanced to a level where users, such as pilots and VTS officers, can monitor the vessel progress and underkeel clearance (UKC) in real-time and assess how changes in vessel speed can optimise vessel squat and trim. This paper describes the how squat predictions are used in operational conditions and how realtime speed control is used to optimise vessel squat and trim for underkeel clearance purposes. Three case studies of operational systems are presented.