Based on an analysis of information from the deck logbooks of several U.S. dry cargo ships operating primarily in the North Atlantic service, a comparison was made between actual time spent at sea and ideal sea time ( perfect conditions and minimum distance assumed ). The extent of lost time at sea was thus determined, and causes for that lost time identified as to: 1. Voluntary slowdown because of slamming, shipping water, pitching, rolling and other causes. 2. Involuntary slowdown because of variations in displacement; fouling; additional miles traveled; and wind, waves, currents and other similar causes. The study determined that for three ships subjected to a complete analysis covering a total of more than 16,000 hours of sea time, the overall average of all time lost amounted to about 3,600 hours, or 22 percent of total sea time. The most significant cause of lost time was the natural involuntary wind, wave and current factor which accounted for a loss of 12 percent of total sea time. Next in order of importance were voluntary slowdowns ( 5 percent ), extra miles traveled ( 4 percent ) and fouling ( 1 percent ).

  • Supplemental Notes:
    • This Research was sponsored by Panel H-7 ( Seakeeping ) of the Hydrodynamics Committee
  • Corporate Authors:

    Society of Naval Architects and Marine Engineers

    601 Pavonia Avenue
    Jersey City, NJ  United States  07306-2907
  • Authors:
    • Zubaly, Robert B
  • Publication Date: 1969-8

Media Info

  • Features: Figures; Tables;
  • Pagination: 22 p.
  • Serial:
    • T&R Bulletin
    • Issue Number: R-11
    • Publisher: Society of Naval Architects and Marine Engineers

Subject/Index Terms

Filing Info

  • Accession Number: 00010308
  • Record Type: Publication
  • Source Agency: Society of Naval Architects and Marine Engineers
  • Files: TRIS
  • Created Date: Feb 25 1972 12:00AM