Skip to main content

T&R Bulletins & Reports

Publications - Bulletins

Technical and research (T&R) | Bulletins and reports

Reset
In the past bow bulbs were supposed to be unsuitable for slow, fullform ships. However, the present study reveals that they can cause a considerable reduction of resistance in the ballast condition. This property has been confirmed by model tests and full-scale operation in practice. Parameters for effective bulb design are indicated. The sensitivity to weather conditions and the economic significance of bulbous bow ships are investigated. The second part of the paper describes a series of special experiments conducted with a tanker model for clarifying the physical mechanism by which the bow bulb reduces the resistance of slow, full-form ships. The tests comprised measurements of resistance, viscous wake and wave pattern as well as flow observations by means of film and underwater television. It was found that contrary to previous hypotheses the bulb produced its effect not so much by wave cancellation or improved flow around the bilge as by elimination of the breaking bow wave.
 
List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00

This Bulletin is a condensation of available practical information on the various aspects of ship propeller forces and propeller-induced hull forces arising from the spatially non-uniform flows to which almost all ship propellers are subjected. The work embraces brief physical descriptions of the manner in which blade frequency pressures are generated by propellers; the attending induced pressures on nearby structures to produce hull forces; the forces on the propeller itself and the blade-bending moment and a distillation of experimental results from model tests and full-scale measurements which reveal the dominant effects of certain parameters as currently exhibited.

 

List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00
Results are presented of an extensive stratified random sampling of spectra obtained by analysis of wave records at Station "India" in the North Atlantic Ocean (59DN, 19°W). Spectra were obtained for five different wind speed groups, and except in the highest wind group represented a roughly equal sampling of all four seasons. The final sample of 323 spectra are presented in graphical and tabular form in an appendix, along with tabulations of the principal spectrum parameters. The report presents the results of analysis of the spectra to show a variety of trends, such as significant height vs. wind speed and average period, seasonal variations in significant height, etc. Typical groups of spectra having significant heights of 25-35 feet and 35-45 feet are presented graphically and compared to several ideal spectrum formulations, showing considerable differences. It is concluded that this collection of spectra can be grouped into families, on the basis of significant wave height, which can be useful for ship designers.
 
List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00
The ability to quickly relate printed material on sailing yacht studies, depends primarily on the use of accepted standard nomenclature. Through thorough study and collaboration the present recommended standards have been listed. This material should serve as a guide to preferred usage for new work and leave some flexibility to accommodate those with previously established procedures.
 
List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00
This report summarizes available maximum ocean wave characteristics for use in design. The wave characteristics have been determined from a survey of published data obtained from wave recording instruments, and both wave height and period data and wave spectral density are covered. Available wave data sources are reviewed together with the global distribution of dam. Uses of maximum wave data in design are discussed and high wave records and wave spectra are included in appendices to this report.
 
List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00
This report presents the results of an analysis of a limited sample of wave records obtained by two weather ships at Station "Kilo" in the North Atlantic. The data is comprised of 93 records which are distributed uniformly by season. Each sample was digitized and a spectral analysis was performed. Various spectral parameters were then calculated. In addition, each record was scrutinized manually to determine the maximum peak-to-mean value and the mean period. The statistical properties of selected parameters, and correlations with log book data, such as observed wave height, wind speed and wind direction, are presented numerically and graphically. The principle characteristics and ordinates of each spectrum are listed and plotted in the Appendix to this report.
 

In addition, the wave spectra are organized into spectral families, based on wave height and wave period groups, to facilitate comparison of general characteristics. It is concluded that the overall trends derived from the analysis confirm the observations made for Station "India" and Station "Papa." However, the small number of samples is judged to be insufficient for determining long term trends or for direct comparison with other ocean locations.

 

List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00

In a series of chapters, Professor Lewis has compiled a report on the status of seakeeping research in the united States as applied to commercial type ships. After an introduction, the report covers theory, data and needed research as regards the environment, ship motions, derived responses, applications, and concludes with a summary of needed seakeeping research. This report conveys the opinions of Professor Lewis, Panel H-7 and the Hydrodynamics committee and does not necessarily reflect the opinion of the SNAME as a whole.

 

List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00

This Bulletin is a bibliography containing abstracts of journal articles and reports on various aspects of ship control and controllability published in 1982. It is divided into 32 sections covering specific aspects of controllability and vessel types. This Bulletin is a historical reference.

 

List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00
T

T&R Bulletin 1-41 (1983) supersedes existing the T&R Bulletin 1-27 (1966).

 

Ship control considerations in recent years have included a greater appreciation of environmental situations, a significant increase in the size of ships, and the use of computer technology and simulation. These have made it necessary to revise end update The Society of Naval Architects and brine Engineers Technical and Research Bulletin No. 1-27, the "Notes on Ship Controllability, 1966". These notes are intended to provide guidance for vessel designers and owners on questions fundamental to good design leading to acceptable maneuvering and controlla­bility of vessels. This Revision retains the useful material of the 1966 notes, and includes new and expanded material developed from advanced technology. The subject matter is limited to topics of immediate importance and is not intended to replace, but rather to supplement the SNAME publication entitled, "Principles of Naval Architecture".

 

List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00

Tables (73) representing the data file on Resistance Coefficients of Barges from the Ship Hydrodynamics Laboratory of the University of Michigan are presented. Raw barge data were collected for 125 barges at light, ballast and full-load drafts. Appendices list recorded variables, and the speed/length ratio calculation with other notes.

This report is advisory only, and there is no implication of warranty by the Society that use of the figures herein will ensure certain performance.
 
List Price: $40.00
Member Price: $20.00
Student Member Price: $20.00
NOT A MEMBER YET?
NOT A MEMBER YET?