出版社：Defence Scientific Information & Documentation Centre
摘要：The with is limited by the paucity of mine-sweepers that can be engaged continuously on the job. The width should be sufficient to cover the likely lateral sets in a ship's passage upto 30 fathom line. In calm weather and most of the channel length coinciding with direction of currents of any, the required channel width is less than 100yds. and may be swept again and again by the same two mine-sweepers (LL sweep). In rough weather or when direction of currents and drifts is different, in order to use the above narrow channel Decca navigation should be provided. Electric or Magnetic field of a Guide Cable can also be used; making buoys can be used but they are not entirely dependable on account of drifts or interference or use by enemy.
关键词：Harbour entry swept channel;Optimum width;Electronic or magnetic field
