An earthmoving contractor involved in undersea land reclamation for the expansion of a manmade airport peninsula planned to use its own barges to deliver and unload fill materials at a specially equipped harbor with three unloading berths. Loaded barges had to be towed by a tugboat to enter the harbor, to dock at the unloading berths, and to return to the open sea. At the same time, the harbor had to be shared with other vessels that would interrupt the contractor’s operations. Four STROBOSCOPE simulation models were developed to investigate alternatives the contractor considered to improve system performance. These included the provision of additional material from another supplier with its own barges, and the use of position-tracking equipment to optimize the tugboat's movement when not towing a barge. Four animation models were used to verify, investigate, and communicate the simulation models. These models illustrate the use of runtime system information to facilitate dynamic decisions that would interrupt the tugboat when traveling alone and reassign it to barges that needed its services. Simulation results showed that the tugboat's dynamic reallocation did not occur often enough to make a marked difference in performance. The simulation results also advised against adding additional barges from another material supplier. They would have created a bottleneck at the harbor entrance with little improvement in production.