What is the fundamental frequency for a vessel of less than 75 meters in length?

The fundamental frequency for a vessel of less than 75 meters in length is correctly identified as falling within the range of 250-700 Hz. This frequency range is significant because it relates to the natural frequencies of smaller vessels, which are generally influenced by their size, hull shape, and the dynamics of their movement through the water.

In vessels of this size, the fundamental frequency is critical for understanding how they interact with wave patterns and external forces, as well as for the design of onboard systems to minimize issues such as resonance or vibration. The specific range of 250-700 Hz is representative of the typical acoustical characteristics and vibrational responses of vessels in this length category, providing insights into their behavior and ensuring that engineering design accommodates these physical principles.

Each of the other choices provided represents frequency ranges that are either too low or too high for vessels of this size. These ranges would typically pertain to larger vessels or different types of structures that do not align with the expected acoustic properties of smaller boats, making them less applicable in this context.