Glossary of maritime terminology

Radar, or marine radars, are X-band or S-band radars used on ships. Radar is used when a vessel is underway to detect land obstacles as well as other ships. Radar aids in navigation and is crucial for collision avoidance by providing distance and bearing.

The Radiotelephony Spelling Alphabet, most often referred to as the NATO Phonetic Alphabet or simply the Phonetic Alphabet, is the most commonly used group of code words used to clearly communicate the letters of the Roman alphabet, particularly over the radio.

Its formal name is the International Radiotelephony Spelling Alphabet however, you may also hear the alphabet called the NATO Spelling Alphabet, the ICAO Phonetic Alphabet and the ICAO Spelling Alphabet. (ICAO being the International Civil Aviation Organization.)

The code words used, from a to Z are: Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, Xray, Yankee and  Zulu.

Note that Alfa and Juliett are intentionally spelled ‘incorrectly’ to avoid any confusion caused by their original spellings - i.e. Alpha and Juliet - being mispronounced.

In maritime terminology, a raft is any flat structure that is used for transportation or support on water. Rafts are normally typified by their basic design, and unlike boats, they do not have a hull. A raft is usually kept afloat by the use of buoyant materials such as wood, sealed barrels, or inflated air chambers.

Rafts do not normally have an engine and are instead propelled by oar by a person standing upright. Rafts are also used for leisure purposes and can be attached to the bottom of a river, lake or sea for swimmers and sunbathers to relax upon. 

A seafarer’s rank is their job title or position. Ranks work on a system of hierarchy, both in the military and in the merchant navy / merchant marines. The highest rank on a vessel is the Master (or Captain) with entry level seafarer jobs such as Deck Cadet and Wiper being lower ranks.

Ratings is a general maritime term used to describe a skilled seafarer who works in a support role on a vessel. Ratings can work in any department (i.e. Deck Department, Engine Department or Stewards Department) and their tasks vary depending on their rank (see above) and job. A crew is made up of Officers and Ratings. To put it in the same terms as a job on land, such as that in an office or warehouse, an Officer (e.g. a Chief Officer) has management responsibility while a Rating is part of the ‘workforce.’ 

A red parachute flare, also known as a parachute rocket flare or parachute flare, falls under the category of life saving appliance and is a visual aid that draws attention to a boat or ship in distress. Parachute flares are long range aids that project an extremely bright signal that floats back down to earth from a small parachute.

These flares are brighter than handheld flares and can reach a height of around 300 meters / 1000 feet and they burn for approximately 40 seconds. On a clear day or night, red parachute flares can be seen at a distance of approximately 28 miles or 45 kilometers.

A reef is a geographic feature such as a ridge or shoal of rock, coral, sand or other similar material that lies beneath the surface of the ocean or other natural body of water. Reefs are relatively stable and can cause vessels to run aground if those responsible for navigation are not careful.

In maritime terminology, a reefer box is an insulated shipping container designed to carry cargo such as fresh food and other produce that needs to be temperature controlled.

A reefer container, or reefer box, is an insulated shipping container designed to carry cargo such as fresh food and other produce that needs to be temperature controlled.

A reefer management system, also known as a reefer monitoring system, is used to monitor and control the temperature, humidity levels and O2 and CO2 levels in a refrigerated container - also known as a reefer container or reefer box.

A reefer monitoring system, also known as a reefer management system, is used to monitor and control the temperature, humidity levels and O2 and CO2 levels in a refrigerated container - also known as a reefer container or reefer box.

The reefer plant, also referred to as the refrigeration plant, on a vessel is used to ensure that certain types of cargo, as well as food and provisions for the passengers and/or crew, are kept at a low enough temperature so that they don’t spoil. The plant consists of various parts and machinery such as heat exchangers, compressors and valves that are interconnected through a series of joints and pipes.

A reefer ship is a container ship that has refrigeration and is used for transporting frozen foods such meat, fish and ice cream as well as produce that needs to be kept chilled such as fruit and dairy products.

The refrigeration plant, also referred to as the reefer plant, on a vessel is used to ensure that certain types of cargo, as well as food and provisions for the passengers and/or crew, are kept at a low enough temperature so that they don’t spoil. The plant consists of various parts and machinery such as heat exchangers, compressors and valves that are interconnected through a series of joints and pipes.

In shipping terms, the remote control valve system (rcVS), sometimes also called a valve remote control system (VCR), on a ship is used to control various pumps such as the bilge pump, fuel transfer pump, fire pump and ballast pump. It directs the flow of the fluids and liquids that work with these pumps - for example fuel oil, ballast water or bilge water. The valves are opened and closed remotely by electric, pneumatic, hydraulic, or electro-hydraulic actuators.

A rescue boat is a small vessel that will be deployed to assist during emergencies and rescue operations. It is not the same as a lifeboat, which is a survival craft (in shipping terms, rescue boats are not classified as such) and is used to sustain the lives of the crew or passengers who have had to abandon ship. A rescue boat, however, will be used in any situation as required. For example, if someone has fallen overboard or has been stranded at a remote location, or if the vessel is sinking.

Return cargo is a freight term used to describe it when a ship returns with additional cargo to the port where the initial cargo was loaded.

Rigging refers to the system of cables, ropes and chains that are found on a sailing ship, sail boat or sailing yacht. This system supports the mast or masts and is used to adjust the position of the boat’s sails and the spars to which they are attached. 

A roll-on / roll-off ship, also called a ro-ro, ro/ro or roro ship allows wheeled cargo to be driven on board rather than be loaded by crane. This could be a cargo of new cars or vans, but ro-ro can also refer to passenger ships such as ferries and military transporters which carry tanks. 

Rolling cargo is a freight term given to cargo that has wheels - such as cars, trucks, trailers, buses or even tanks - which can be driven on to a ship. (See roll-on/roll-off ship above.)

Romeo stands for the letter R in the International Radiotelephony Spelling Alphabet, which is most often referred to as the NATO Phonetic Alphabet or simply the Phonetic Alphabet. This is the most commonly used group of code words used to clearly communicate the letters of the Roman alphabet, particularly over the radio and is essential in helping seafarers give and receive messages, orders and instructions clearly and correctly.

A RoPax ferry transports vehicles (roll-on roll-off) as well as passengers (pax).

A ro-ro ship, ro/ro ship or roro ship allows wheeled cargo to be driven on board rather than loaded by crane. This could be a cargo of new cars or vans, but ro-ro can also refer to passenger ships such as ferries and military transporters which carry tanks. Ro-ro is short for roll on / roll off.

A rudder is the primary method of control that is used to steer a ship or boat, or even a submarine or hovercraft. It is an underwater blade that is positioned at the stern (back) of a vessel and controlled by its helm. When that is turned the rudder will also turn and steer the bow of the ship in the same direction.

Rudder bearings on a ship or boat act as the pivot point for the rudder, allowing it to turn and direct the vessel. These bearings are usually made from robust materials like stainless steel or bronze as durability is paramount and the bearings must be able to cope with the forces and demands of sailing, whether that’s on a sailing yacht or a container ship.

Running aground or grounding is a maritime term used when a ship touches or hits the ground in a shallow part of the sea, a river, lake, canal or other waterway and gets stuck.