A vessel not under command sounds the same fog signal as a vessel:

The correct answer is that a vessel not under command sounds the same fog signal as a vessel constrained by her draft, under tow, or under sail, as all these types of vessels must signal their presence in foggy conditions.

A vessel not under command is unable to maneuver as required, often due to a mechanical failure or some other reason that leaves it incapacitated. Its fog signal consists of two prolonged blasts followed by two short blasts, a signal that indicates its inability to navigate normally.

Similarly, vessels constrained by their draft, which means they cannot safely navigate into shallower waters, are also required to sound the same signal under the International Regulations for Preventing Collisions at Sea (COLREGs). This helps inform nearby vessels of their limitations and enhances safety on the water.

The same applies to vessels under tow, as they may also have limited ability to maneuver due to their connection to the towing vessel. These vessels sound the same signals to ensure that their presence is recognized and that other vessels can take appropriate action to avoid collisions.

Vessels under sail make the same fog signal because they also have unique navigation constraints, primarily relying on wind for movement, which may limit their capability to maneuver away from potential hazards.

Since all these vessels