), acoustic (bells, sirens, gunshots, etc.), or radioelectric (telegraphy, radio).

Acoustic signal consisting of seven short blasts and one long blast transmitted by the ship’s public address system.

Metal box filled with holes, placed at the ends of the suction tubes of the bonbas to prevent the entry of foreign bodies.

Length of the ocean surface over which the wind blows at a specific speed and direction.

It is the maximum distance from which it is visible, whose limits are the curvature of the Earth, the height of the light and the height of the observer.

It is the maximum distance from which it is visible, whose limit is only the intensity of the light.

Space, on the upper deck of ships, between the mainmast and the stern or poop.

Small portable projector used on board ships to make light signals using Morse code.

Cavity or groove that is ballasted in the stem, keel and stern of a wooden boat, so that it fits the strapping wire.

Announcement to specified areas that a hurricane is likely to threaten within the next 36 hours.

Radio signal from a ship in distress automatically directed to a maritime rescue coordination center, indicating the ship’s position, identification, heading and speed, as well as the nature of the danger.

Announcement to specific areas that a tropical storm threatens within 36 hours.

On a yacht, an angular appendix at the bottom of the keel that provides righting and reduces sag.

They are active-type stabilizers, made up of one or more pairs of adjustable rudders, around their horizontal axis, and which are projected on the sides of the live work. From a functional point of view, each fin behaves like the wing of an airplane, creating a positive or negative lift force. Applying angles of incidence of the same value, but of the opposite sign, to the fins of both symmetrical centerline planes, the forces causing the roll are largely counteracted.

Series of signs or signals used to communicate with each other two ships, a ship and an airplane or a ship and a ground station. Conventional alphabets are those used by signal flags, projectors, and optical and radio telegraphs. The alphabets that are used or have been used the most are Morse (for both radio and light signals), for flags and ICAO phonetic (for radiotelephony).