ASSESSING SURFACE DETERIORATION

The Author discusses the loss of performance due to really bad roughening of the hull by organic fouling or surface deterioration. Such roughening can reduce a ship's speed by 10 to 15% or more. Although very deleterious, organic fouling is easily removed and there is little permanent harm; however, although much less marked, roughening due to breakdown of paint system, minor pitting, inadequate preparation of the surface for painting, or insufficient care in the application of the compositions can be economically significant and tends to accumulate over the life of the ship. It is with the monitoring of such deterioration and its quantitative assessment that this paper is concerned. An analysis of a large number of trials results on both old and new ships suggests, as a practical working rule, that approximately 1% more power is required to maintain a given speed for every 10 microns increase in roughness; this applies to the normal range of roughnesses above 100 microns and the power is probably even more sensitive to roughness below 100 microns. The electronic roughness analyser gauge recently developed by B.S.R.A. gives an immediate print out of maximum peak-to-valley values in microns for each 50 mm sampling length. Order from BSRA as No. 49,689.

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  • Supplemental Notes:
    • Paper presented at a conference on Hull Surface Maintenance: Its Role in Operating Economics organised by BSRA in 1977. Paper appeared in Motor Ship, Special Feature, Volume 58.
  • Corporate Authors:

    IPC Industrial Press Limited

    Dorset House, Stamford Street
    London SE1 9LU,   England 
  • Authors:
    • Parker, M
  • Publication Date: 1978-4

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Filing Info

  • Accession Number: 00195388
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Jul 31 1979 12:00AM