SHIP PERFORMANCE IN ROUGH WEATHER

The author, who is head of Sea-keeping Research at AEW, Haslar, discusses the behaviour of Royal Navy vessels in rough weather. During World War II it was found that although high-powered destroyers were capable of making 35 knots in calm water, such severe reductions of speed were imposed in rough weather to avoid damage to the ship, that the available power was hardly ever used. Later, the development of spectral techniques allowed statistics of ship motions in rough weather to be predicted from the results of model tests in regular waves. Sea keeping is of particular interest to destroyers and frigates as these vessels are often required to maintain speed alongside larger ships during escort duty and, being smaller they are more vulnerable to rough conditions. The ship designer may be required to achieve certain speeds in calm and rough weather for a given power, provide a safe and efficient operating platform for a helicopter and other weapons, and ensure that the ship will have adequate stability and safety against capsize. For this a reliable design method is needed and in recent years AEW has been developing design methods for various aspects of performance in rough weather based on the findings of its own and other researchers. Recent investigations have shown that there are many different ways in which a ship may capsize. In particular, stability is reduced when the bow and stern are in wave troughs and a wave crest is midships. If the wave is travelling at the same speed as the ship the loss of stability may become so great that the ship simply falls over. This mode of capsize is ignored in all current stability regulations. AEW is involved in a joint programme of research with the National Maritime Institute to further the understanding of this problem with the eventual aim of developing new criteria for safety at sea.

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  • Corporate Authors:

    Royal Institute of Navigation

    Royal Geographical Society, 1 Kensington Gore
    London SW7,   England 

    Royal Institute of Navigation

    1 Kensington Gore
    London,   England 
  • Authors:
    • Lloyd, ARJM
  • Publication Date: 1978-1

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Filing Info

  • Accession Number: 00177261
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Jul 19 1978 12:00AM