Squat can be defined as the downward change in vertical position which every displacement ship experiences when under way. This reaction is normally accompanied by a change in longitudinal trim. It is the combination of these reactions which we refer to as squat. The two main factors which cause an increase in squat, and consequently an increase in draft, are increasing speed and decreasing under keel clearance. It is this second factor, shallow water, which has assumed an increasing importance in recent years. For economic reasons, the trend to increase the size of oil and bulk carriers has continued. For these very large ships, with drafts greater than 20 metres, large areas of the North Sea, English Channel and many other shipping lanes throughout the world, now present shallow water conditions. This paper, which contains typical examples of the results of a 6 year research programme, presents the case for a continuous reading squat-draft indicator, as an anti-grounding navigation aid. The results of model experiments and full scale data for a VLCC on route from the Persian Gulf to Europe and a high speed ship in deep water, are presented together with the experiment technique used for the full scale measurements. The practical application of the development of the full scale experimental technique as a bridge navigation instrument is discussed.

  • Corporate Authors:

    Royal Netherlands Naval College

    P-de Hoochweg
    129 Rotterdam,   Netherlands 
  • Authors:
    • Ferguson, A M
  • Publication Date: 1975

Media Info

  • Pagination: n.p.

Subject/Index Terms

Filing Info

  • Accession Number: 00323585
  • Record Type: Publication
  • Source Agency: Stevens Institute of Technology
  • Files: TRIS
  • Created Date: Mar 12 1981 12:00AM