<p>Ports are major infrastructures subject to multiple constraints, such as seasonal variability of ship arrivals, tides, availability of docks and tugs, and sometimes even waterways with restricted access. All these characteristics are combined at the Port of Quebec, which is close to the <i>Traverse Nord</i>, a narrow strip of seaway highly affected by tides, acting as a variable-depth canal. While many of these characteristics are directly related to the St. Lawrence River, such as the tides or types of ships that pass through the seaway (often towards other ports), some others are under the control of the port authority, such as dock and berth allocation, tug usage, and the management of the Traverse Nord, which is also the major gateway for inland ports in Canada and the United States, all the way to the Great Lakes. To enable port authorities to evaluate different operational alternatives and perspectives, we have developed a simulation and optimization system based on data from the Port of Quebec, which allows us to quantify the impact of managerial decisions on the waiting time to access a tug. The developed simulation includes queueing systems, speed optimization, passage priorities, and berth and tug allocation. The impact of dock and tug management is clearly demonstrated, as well as the importance of adequate traffic planning that must pass through the Traverse Nord seaway. Our simulation can be used as a decision-making tool by port authorities, giving visibility to short-term operational decisions and long-term planning strategies.</p>