Dracone Barge

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A Dracone Barge is a large flexible watertight tube intended to carry a liquid cargo while towed mostly-submerged behind a ship. One large current example of the type has a capacity of 935 cubic metres (4.23m diameter, 91m long) while weighing only 6.5 tonnes empty.

The Dracone Barge was invented in 1956 by Professor William Hawthorne[1] as a new type of oil tanker. The intent was to create an improved transport technology: the long tube can be pulled by a lower powered vessel than the equivalent tanker, the cargo can be handed off at the destination very quickly, and incurs no drag cost when empty (because it can easily be taken aboard), as compared to the similar unladen to laden drag of the rigid-hulled tanker of equivalent capacity.

The common modern use (described in a patent application filed by BP in 1972[2][3] in combination with capture booms) is in the clean-up of petroleum spills or pollution slicks, where any small and manouevrable vessel (e.g. a harbour tug) with pumping gear mounted on it can gather up a much larger volume of liquid than it can carry by pumping it promptly back over the side into a tanker or Dracone Barge.[4] A secondary, but related use, is the offloading of bilgewater from large ships that must be treated (at a shore-side facility) and not dumped directly into the sea.

The vessels were given the name "dracone" as it was "the nearest word in Greek for a mythical monster such as a sea serpent."[5] However, one year earlier Frank Herbert wrote his first novel The Dragon in the Sea about submarines towing large bags to carry oil, and other sources say the naming was an "overt acknowledgment of the source of his idea". While being towed by a vessel, they display only one all round light placed at their stern so that it can be seen by other vessels and risk of collision can be avoided.[6]

See also[edit]

It should be noted that according to the USCG's 72Colregs, Dracones less than 25 meters breadth (82.02') should display one all-round white light at each end. However, the "forward" light may be omitted. However, dracones with a breadth of 25 meters or longer MUST display one all-round white at each end and two additional all-round white lights on each side of its maximum breadth. Dracones exceeding 100 meters shall display additional all-round white lights between the fore and aft lights not to exceed 100 meters between these additional lights. While being towed by a vessel it displays only one all round light to avoid any collision.

Notes[edit]

  1. ^ The Science News-Letter, Vol. 74, No. 21 (Nov. 22, 1958), p. 325
  2. ^ GB application 1435495, British Petroleum CO, "Oil Clean-Up Method", published 1976-05-12 
  3. ^ Hawthorne, W.R.; Swinnerton-Dyer, P. (1957). "The stability of a towed flexible tube". Dracone Development Limited. Report No. 7. 
  4. ^ "Dracone Barges Helping to Clean Up the Environment". Universal Rope Fabrication Ltd. Retrieved 2009-05-09. 
  5. ^ "The Papers of Sir William Hawthorne". Janus. Retrieved 2009-05-09. 
  6. ^ O'Reilly, Timothy (1981). "Chapter 2: Under Pressure". Frank Herbert. Frederick Ungar Publishing Co., Inc. Retrieved 2009-05-09.