The paper outlines design assumptions and illustrates some problems the designer faces when attempting to correlate design alignment calculations with practical checks made during and after installation, examples being taken from recent new buildings ranging from 250,000 dwt turbine tankers to cross channel ferries. In scope the paper encompasses the principle objectives and basis of shaft alignment calculations, the basic gap and sag method of alignment in ship and typical gap and sag instructions, extensions of previously discussed methods to the particular cases of aligning a shaft system to a slow speed diesel engine, the results and comparison of alignment calculations with and without the engine crankshaft included as part of the shaft system, the effect of offset propeller thrust on shaft alignment with discussion on the possible consequences of adapting an alignment to accommodate offset thrust, methods of checking stages of onboard installation and the correlation between theoretical predictions and practical results. The paper concludes with an account of difficulties met in establishing alignments in new buildings, re-establishing alignment in ships which have been in service and in ships with the shaft system coupled, and a reflection on the adequacy of current techniques judged by service experience and absence of mishaps.

  • Supplemental Notes:
    • 45 Conference Papers presented at IMAS 73, London, 4-8 June 1973, organized by the Institute of Marine Engineers. This paper is available only in a set of 6 papers in Subject Group 9: "Stern Gear, Shafting and Propellers" at $10.00.
  • Corporate Authors:

    Institute of Marine Engineers

    Memorial Building, 76 Mark Lane
    London EC3R 7JN,   England 
  • Authors:
    • Wilkin, T A
    • Strassheim, W
  • Publication Date: 1973

Subject/Index Terms

Filing Info

  • Accession Number: 00048486
  • Record Type: Publication
  • Source Agency: Institute of Marine Engineers
  • Files: TRIS
  • Created Date: Nov 14 1973 12:00AM