Sea supply

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Tanker Harz supplies destroyer Hamburg of the German Navy (1971)

Under underway replenishment (NATO: Replenishment at Sea / RAS or Underway replenishment / UNREP ) is the Replenishment at sea befindlicher warships with supplies, spare parts, food, ammunition and other supplies and personnel transfer. The sea endurance of a warship can be considerably extended by sea supply maneuvers.



Bravo flag

Standard sequence of a refueling maneuver:

  1. Extensive clarification of the lake area
  2. Preparations are the assembly of the filler neck and the dismantling of the railing.
  3. The ship that requires fuel approaches the supplier from starboard aft and maintains a parallel course at a distance of 30 to 60 meters at the same speed.
  4. The connection is first made by a line that is shot from one ship to the other with the bola .
  5. A wire is overtaken on this line, stretched between the highest point of the refueling system and the RAS tree, along which the fuel hose runs.

Usually another line connection is made between the bugs of the two ships; Small colored flags are attached to this, which can be used to read the distance between the two ships, the so-called distance line.

In addition to the general dangers of taking over fuel or ammunition (smoking is prohibited on the entire ship for the duration of the maneuver), there is another additional risk for supplies at sea: If the two ships are too close to each other, the flow velocity between the two ships will vary Increase the water flowing through ships, which decreases the water pressure at this point ( Venturi effect ). This can lead to the two hulls being sucked together. Therefore, in the run-up to a RAS maneuver, the speed and distance of the ships must be calculated and then precisely adhered to. As a rule, only very experienced bridge personnel are employed here.

The simultaneous fuel supply of two ships on both sides of the tanker (fuel transporter) is possible.

After the end of the supply, the unit taking over usually thanks with a special gesture such as playing the ship's anthem or another selected piece of music. After taking over the beer, the big flag of the brewery is set.

Transfer of people

Transfer of people between destroyer Lütjens and a tanker of the German Navy (1981)

At the giver, the manila line is lashed amidships above man's height. The free end of the taker is led over a block and held by (many) crew members. Only human strength and intuition can keep the line taut despite the fluctuations caused by the sea. On the manila line, the double roller carriage is pulled over with the hauling and safety line. Baskets or nets for the material transfer hang on it. People are transported in cages, hip belts or trouser buoys .


Simultaneous transverse and helicopter supply for the USS George Washington : While fuel is being transferred using several hoses, two helicopters are shuttle transporting goods pallets

In the USNavy and other navies with large supply vessels, solid supplies are often transferred by helicopter during the delivery of fuel. This process, known as Vertical Replenishment (VERTREP), is faster than the transfer of pallets using dishes.

Web links

Commons : Replenishment at Sea (RAS)  - collection of pictures, videos and audio files

Individual evidence

  1. Recommendations (US Navy)