What is the maximum allowable current velocity through a harbor entrance?

In the context of harbor design and marine engineering, the maximum allowable current velocity through a harbor entrance is critical for navigation safety and operational efficiency. The recommended limit of 1.5 m/s or approximately 3 knots reflects the balance between allowing sufficient water movement for proper circulation and minimizing risks to vessels entering or leaving the harbor.

This velocity limit helps to ensure that vessels can maneuver safely without experiencing undue drag or difficulties in handling. Stronger currents can challenge the control of larger vessels and increase the likelihood of accidents, which is why regulations often set a maximum limit. Furthermore, this standard can also account for the influence of tidal flows and river discharges, ensuring that maritime operations remain safe and efficient.

While some other options presented might seem feasible, they exceed the acceptable limits for safe navigation within a harbor environment, thereby making them less appropriate choices compared to the recognized standard of 1.5 m/s or 3 knots.