A SEAKEEPING TEST ON A CONTAINER SHIP "AMERICA-MARU" ON THE NORTH PACIFIC OCEAN

Results of a seakeeping test on a container ship "America-maru" of Mitsui O.S. Lines Ltd. on the North Pacific Ocean are reported. The test was planned according to the ten-years' plan on the ship tests of the Ship Research Institute and as a collaborational investigation with the Shipbuilding Research Association of Japan. Pitch, roll, yaw, rudder angle, vertical and lateral accelerations at F.P. and longitudinal acceleration at the navigation bridge were measured and recorded on a Magnetic Data Recorder and on a "Visigraph" recorder. Weather, atmospheric pressure, visibility, air and sea water temperatures, humidity, wind direction and the Beaufort scale, directions and scales of wave and swell, position of the ship, main engine revolution, super charger revolution, fuel handle notch, governor index and fuel oil consumption are recorded from ship's log book. Compass course, relative wind direction and speed, ship speed, brake horsepower, auto-pilot adjust, rudder angle and roll angle were read from the indicators of the ship. Period, height and encounter angle of swell, height and encounter angle of wave shipping water, slamming, shock or shudder, propeller racing, changing course and speed, damage of hull and containers and seasickness were recorded based on visual observations. The measurements were carried out three times a day, each lasting 20 minutes at 7:50, 11:50 and 15:50. A comparative test upon the action of anti-rolling tank was carried out once. The results of the measurements are graphically shown in the form of daily variation. Once each in the outward and homeward voyages, a rough sea state was encountered. The maximum amplitudes of pitch and roll were 5.0 degrees and 15 degrees respectively, and that of the vertical acceleration reached 0.75 g. The ship meets mostly following or quartering seas in the outward voyage, and head or bow seas homeward. In the latter condition, two-nodal vibrations were often experienced. The indication of the ship's clinometer proved to be bigger than the actual one. The real inclination seems to be 60 to 80 percent of the indicated value.

• Corporate Authors:

  Ship Research Institute, Tokyo

  38-1, 6-chome, Shinkawa, Mitaka-shi
  Tokyo,   Japan 

  Ship Research Institute, Tokyo

  38-1, 6-chome, Shinkawa, Mitaka-shi
  Tokyo,   Japan 
• Authors:
  • Ogawa, Atsushi
  • Sato, T
  • Kokubo, Y
• Publication Date: 1971-3

Language

• Japanese

Media Info

• Features: Figures; References;
• Pagination: p. 25-37
• Serial:
  • Ship Research Institute, Report of
  • Volume: 8
  • Issue Number: 2
  • Publisher: Ship Research Institute, Tokyo

Subject/Index Terms

• TRT Terms: Seakeeping; Seaworthiness; Ship motion
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00033657
• Record Type: Publication
• Source Agency: Ship Structure Committee
• Files: TRIS
• Created Date: Jul 28 1973 12:00AM