The Society of Naval Architects and Marine Engineers released
a 60-page technical bulletin Practices and Procedures for the Alignment of Marine Main Propulsion Shafting Systems
. The bulletin was compiled by the Propulsion Shafting Panel, Panel M-16
, of the Society's Technical and Research Program.
While industrial machinery is typically aligned so that the shafts of the driving and driven machines are collinear, this approach is not appropriate for marine main propulsion shafting because the bearings move as conditions change, and because the shafting is never really straight as it deflects under its own weight and the weight of the propeller and other attached components. Therefore, the vertical and athwartships positions of the bearings must be aligned so that the limits established to ensure proper system operation are not exceeded for all normal ship operating conditions. Ship operators including government agencies have expressed a need for a technical reference guide on the alignment of main propulsion shafting. This document is intended to provide these guidelines for personnel involved in the design, installation, operation, maintenance, and repair of ships. This guide provides a general overview of shaft alignment for the novice, and more detailed information for the expert.
This publication is identified as Technical and Research Bulletin 3-51. It is issued as a CD and may be ordered through the SNAME web site -- www.sname.org -- or by contacting Tommie-Anne Faix email@example.com for $50 ($25 for SNAME members) plus shipping.