MEASUREMENT AT SEA IN THE FORE TANK OF THE LNG CARRIER BEN FRANKLIN

A Working Group, formed by IRCN from six major French shipyards, is studing the motions of liquids in ships' tanks. The paper describes work carried out by the Group, with the co-operation of Bureau Veritas, in prepareation for full-scale measurements to be carried out in the foremost tank of the 120,000-cu m LNG carrier Ben Franklin, and, in particular, describes the intended program of work. This ship, delievered to Gazocean in 1975 by Chantiers Naval de la Ciotat, was still awaiting her first cargo in May 1976. She has Technigaz membrane-type tanks. The program will consist of intensive measurements during one commercial voyage (when the ship will be at the disposal of IRCN for 48 hr), and measurements over a period of two years or more. The instrumentation, which has been installed, includes pressure gauges for the tank, expansion transducers on the trunk deck, accelerometers in various parts of the ship, and strain gauges in the forward cofferdam. The recording unit is provided with analogue/digital converters and a mini-computer. Input will include, where necessary, swell-direction estimates and ship's heading and speed. The data will be processed by IRCN and Bureau Veritas. Work carried out while the Ben Franklin has been awaiting a cargo has included tests on a tank- model which have confirmed the accuracy of Faltinsen's non-linear theory under near-resonance conditions. It is mentioned that, should the occasion arise, the owners may modify the ship for carrying LPG; the consequently lower liquid-levels would be permissible subject to a recommendation that the existing measuring system be used as a monitoring system. The concept of monitoring systems for liquid-cargo motions can be extended to other ship types (OBO carriers in particluar); IRCN and BV agree that the development of a measuring system could be regarded as the development of a monitoring system.

• Supplemental Notes:
  • Seminar on Liquid Sloshing.
• Corporate Authors:

  Norske Veritas

  Grenseveien 92, Etterstad
  Oslo 6,   Norway 
• Authors:
  • Chataignier, P P
• Publication Date: 1976-5

Media Info

• Features: References;
• Pagination: 14 p.

Subject/Index Terms

• TRT Terms: Container tanks; Design; Equipment tests; Free surface; Hulls; Instrumentation; Liquefied natural gas; Ship motion; Sloshing; Structural analysis; Subdivisions; Tanker shipping; Tankers
• Old TRIS Terms: Free surface effects; Hull instrumentation; Lng tank design; Membrane tank systems; Tank instrumentation; Tank testing; Tanker structural analysis; Tanker subdivision
• Subject Areas: Design; Marine Transportation;

Filing Info

• Accession Number: 00152584
• Record Type: Publication
• Source Agency: ish Ship Research Association
• Report/Paper Numbers: Paper No. 8
• Files: TRIS
• Created Date: May 11 1977 12:00AM