T&R Bulletins & Reports

Modern merchant ships have been distinguished by an increase in the features of automation which can reduce the level of manning. This trend towards increased control complexity and reduced shipboard personnel does demand a high degree of reliability in propulsion system controls, steering controls, and vital auxiliary shipboard systems. To assure the required reliability, the maintenance and testing of the machinery, electrical equipment, and controls has to be managed on a continuous, active basis.

T&R Bulletin 3-41 (1988) supersedes the existing T&R Bulletin 3-23 (1970).

The guide addresses the centralized control and automation of steam turbine propulsion plants. Included in the guide are discussions of: machinery operating stations; centralized operating requirements and equipment; and steam generating, propulsion, electrical, and auxiliary machinery control systems. The guide also addresses the control requirements of alternate fuels, combined firing, the application of advanced display and data transmission technologies, and regulatory requirements.

These guidelines present background, experience, and suggestions for implementing a vibration monitoring program for use in the maintenance of ship machinery. The use of systematic vibration measuring and recording in predictive and preventive maintenance of machinery is becoming common in land-based plants, has been used effectively by many ship operators, and is encouraged by the classification societies.

T&R Bulletin 3-43 (2016) supersedes the existing T&R Bulletin 3-43 (1987) and T&R Bulletin 3-10 (1961).

This document provides best-practice guidance on the installation and alignment of propulsion reduction gears in ships and smaller marine vehicles including the small craft of all power levels. The guidelines in this bulletin are written to address any type of vessel regardless of the type of prime mover or fuel source. This guide is intended to assist users in applying standards and to allow the vessel owner, designers, and builders to work together with gear designers and suppliers to achieve practical and successful installations. References are made to applicable standards with the focus on providing an understanding of the important elements to consider and how to best go about achieving successful installations with reliable lasting performance.

T&R Bulletin 3-47 (2015) supersedes the existing T&R Bulletin 3-47 (1989).

This guide covers progressive speed, maneuvering, and endurance sea trials of self-propelled surface ships displacing 300 tonnes or more, powered by hydrocarbon fuels such as petroleum, natural gas or biofuel, and driven by diesel or Otto-cycle engines, gas turbine, or electric motors. References are made to applicable international standards. This Bulletin does not cover dock trials, tests, or demonstrations that can be conducted dockside, which are covered in SNAME T&R Bulletin 3-39, Guide for Shop and Installation Tests. This Guide is intended to assist users in applying IMO maneuvering standards and to allow the owner, designer, and builder to rate the vessel’s maneuvering performance relative to statistical data of vessel maneuvering characteristics. The Guide summarizes the procedures to be used in assessing a vessel’s maneuvering performance.

This report presents the results of a SNAME panel evaluation cable splicing techniques and hardware for application to commercial and navy shipbuilding to support the concept of modular ship construction. The search was for less expensive materials and methods that could at least equal the integrity of the new cable. The various methods of splicing cables were evaluated for the many types of wiring and wiring installations available. The Panel recommendations are based on current technologies; prior studies and reports; performance testing conducted on cable splice connectors; the expertise of the Panel members; conversations with shipbuilders and manufacturers; and the analysis of actual cable splicing techniques and procedures performed.

The purpose of this bulletin is to set forth guidelines, practices, and allowances suitable for use in preliminary stages of the design of marine diesel power plants for the propulsion of typical merchant ships. The bulletin is intended to aid the designer in the use of engine manufacturers' performance data and to report plant design practices. The earlier edition of this bulletin (Marine Diesel Power Plant Performance Practices, 1975) generalized performance data for the ranges of engine types then available.

The rapid evolution of diesel engine design in recent years, leading to engines whose performance data are frequently very different from their predecessors, coupled with the ready availability of performance data published by the engine manufacturer, renders this approach both less reliable and less necessary. Nevertheless, although some generalized data are included in the bulletin, in very early design stages when a particular engine design has not yet been selected, better results are likely if data extracted from current specifications for an engine of the general type most likely to be fitted, can be used. The scope of this bulletin is generally limited to addressing diesel propulsion plants with main engines of the low-speed, crosshead type, and trunk piston engines with outputs as low as 100 bkW (brake kilowatts) per cylinder at speeds up to about 1200 RPM. In attempting to generalize data, uncommon engine types and those not in current production have not generally been included, For the most part, only turbocharged engines have been considered.

The purpose of this bulletin is to present a comprehensive list of resources on the subject of flexible couplings and to provide some guidance on which coupling to use in an application as well as some problems that need to be avoided. It is restricted to marine propulsion drive train flexible couplings, SNAME T&R Bulletin No. 3-20 of September 1968 covers rigid couplings for marine shafting. It is not intended to contain an exhaustive list of flexible couplings or references but is intended to answer the need expressed by shipbuilders, design agents, and maintenance activities in response to a survey by SNAME taken in May 1994.

The scope of this guide is to provide a list of good resources to be used in the selection and maintenance of marine couplings.  All of the references contain very useful information that a designer should be aware of during the design of a power transmission system.  The first reference is a technically sound and particularly comprehensive resource on the subject of coupling design.  Most coupling service problems result from misapplication of a specific coupling type which most often could have been avoided during the design by proper interaction between the power transmission system designer and the coupling manufacturer’s engineering staff.  All major coupling manufacturers provide good technical advice during the design process and with in-service problems. They also provide, because of their extensive background, excellent assistance in failure analysis. 

Common sense suggests that the bearings supporting marine propulsion shafting be aligned so they hold the shaft in a straight line, since offsetting one bearing with respect to another would bend the shaft. Moreover, industrial machinery is typically aligned so that the shafts of the driving and driven machines are collinear [1]. However, this approach is not always appropriate for marine main propulsion shafting because:

a) its bearings move as conditions change, and b) the shafting is never really straight because it deflects under its own weight and the weight of the propeller and other attached components.

Therefore, the vertical and athwartships position 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. It follows that shaft alignment could also be called bearing alignment since the alignment is a direct result of the position of bearings that support the shafts. Ship operators surveyed by SNAME, as well as the US Coast Guard and the US Navy, 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, and operation of marine propulsion shaft lines. This guide provides a general overview of shaft alignment for the novice and more detailed information for the person with some knowledge on one facet of shaft alignment that needs more information on another alignment topic. Ship operators surveyed by SNAME, as well as the US Coast Guard and the US Navy, 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, and operation of marine propulsion shaft lines. This guide provides a general overview of shaft alignment for the novice and more detailed information for the person with some knowledge on one facet of shaft alignment that needs more information on another alignment topic.

This T&R Bulletin contains guidelines for using titanium seawater piping in shipboard marine structures. If the decision for the use of titanium for seawater piping systems has been made for weight and space savings, reduction in maintenance and long economical life, this guide presents experience and lessons learned during the design, fabrication, installation, and testing of six large ships with hybrid titanium seawater piping systems.

This T&R Bulletin is designed to illustrate some of the hurdles that will be encountered during the design, manufacturing, installation, and testing and to provide options and solutions. Recommendations for future Research & Development are also included.