T&R Bulletins & Reports

The purpose of this Bulletin is to document naval architectural practices and conventions used in the estimation and determination of the weight, centers of gravity and weight moments of inertia for surface ships, and to reference sources of weight estimating data for ships and their components for use at various stages of design.

Conventions and practices for offshore drill rigs, high-speed craft, and submarines are mentioned in some instances to demonstrate alternative methodologies but are documented only by references. Military practices and conventions are summarized and referenced but not fully documented.

The purpose of this Bulletin is to document naval architectural practices and conventions used in the estimation and determination of the weight, centers of gravity and weight moments of inertia for surface ships, and to reference sources of weight estimating data for ships and their components for use at various stages of design. Conventions and practices for offshore drill rigs, high-speed craft, and submarines are mentioned in some instances to demonstrate alternative methodologies but are documented only by references. Military practices and conventions are summarized and referenced but not fully documented. Throughout this document, the term weight is used to represent all the mass properties of a ship or object. These properties include the weight, center of gravity, weight moments, and weight moment of inertia.

Technical studies provide insight into leaders that help them make decisions. These decisions can be of small magnitude or could impact the expenditure of billions of dollars and the lives of many individuals. Following repeatable, documented engineering processes to produce reliable and timely technical studies can significantly enhance the quality of these decisions.

This guide was written for engineers and naval architects in planning and executing technical studies.

This document provides a guide to be used during the pre-contract stage of ship design to achieve a "lean" design with reduced work scope. It provides a collection of documented best-practices and design guidelines based on world-class product-oriented ship design processes stressing the need to make all key ship arrangements, system design, and construction decisions early in Basic or Pre-contract Design.

The document is intended as a reference for ship design managers and Integrated Product Teams (IPT) charted with the development of high-quality and low-cost contract designs. Additionally, the guide provides state-of-the-art training material for students of Naval Architecture and Marine Engineering.

Set-based design (SBD) is a method for performing design discovery by way of elimination. SBD is characterized by:

1. communicating broad sets of design values, 2. developing sets of design solutions, 3. evaluating sets of design solutions by multiple domains of expertise, 4. delaying design decisions to eliminate regions of the design space until adequate information is known, and 5. documenting the rationale for eliminating a region of the design space. SBD concentrates on eliminating infeasible and highly dominated regions of the design space. An infeasible region is a region where there is high confidence that a solution does not exist. A highly dominated region is a region where another feasible region is evaluated as being better in every metric of interest. Regions of the design space can be confidently eliminated based on partial information. In SBD, the ultimate solution is obtained incrementally as new information is incorporated.

To be precise, many decisions are made regarding what the solution is not; this occurs as supporting information becomes available. The remaining analysis may focus on reduced design space. In this manner, designs can often be accomplished faster and with greater robustness as compared to traditional methods.

This guide is developed to provide weight classification guidance and process improvements to augment the U.S Navy’s 1985 Edition of the Expanded Ship Work Breakdown Structure (ESWBS). In recent years naval architects and shipbuilders have introduced new technologies into ship designs and construction practices. The current ESWBS classification does not provide adequate guidance on how to use the weight classification for new technologies, systems, and practices. As a result, SAWE and SNAME jointly set up a workshop(s) to identify and provide guidance to address the proper classification of these newer systems for the appropriate assignments in the weight estimates for future ships as well as to provide a means to cross reference previous historical weight data. Also, the workshop(s) reviewed the current ESWBS and recommended modifications to help ensure that the potential of duplications, missed classification of weight data, inconsistencies within ESWBS, and provide greater clarification in the future as well as assist in cross referencing of historical weight data. A technical paper and presentation were made at SAWE’s Annual International Conference in 2015 [1], which documented the initial findings of the workshop. This guide is a result of over a ten-year effort and is intended to be used as guidance to augment the classification of weight reporting using the 1985 Edition of ESWBS [2].

T&R Bulletin 8-1 is a 687 page soft cover book.

The Guidelines for Marine Forensics Investigations, developed by a variety of maritime experts including engineers, architects, historians, anthropologists, filmmakers, and hydrodynamicists, it is intended to be used by professional and amateur investigators in the field of marine forensics investigations.

The detailed manual showcases information gleaned from diving and marine forensic analysis conducted on historic shipwrecks including specific examples from the Titanic, Britannic, Edmund Fitzgerald, Lusitania, Andrea Doria, and Bismarck and many others. Written by leading experts in the burgeoning field of marine forensics investigations, authors include Guidelines for Marine Forensics Investigations editor Sean Kery, Senior Hydrodyamicist, and Vice Chairman of the Marine Forensics Committee, and world-renowned naval architect William Garzke, Chairman of the Marine Forensics Committee of SNAME and Symposium Chairman. Expert in passenger ship design, Philip Sims, Naval Marine Engineer Principal Leader, CSC, and Titanic director and deep-sea underwater explorer and inventor of autonomous underwater 3-D cameras, James Cameron also contributed to the development of the guidelines as well as Paul Henri Nargeolet, who has been the chief investigator of the Titanic wreck and developer of techniques in deep ocean exploration.

Small boat operators, builders, buyers, accident investigators, and others may be required to determine an accurate lightweight and center of gravity for their boat in order to apply stability criteria or perform other analyses. The conventional in-water stability test can be difficult to perform accurately on a small boat, so an air inclining stability test may be specified. This guide is prepared to help standardize and explain the process for an air inclining test. This guide provides the marine industry with an understanding of an Air-Inclining stability test for a small boat. It contains procedures to ensure that valid results are obtained with precision at a minimal cost to owners, shipyards, and the government.

The guide is not intended to direct a person(s) in the actual calculations of the lightweight and centers of gravity, but to be a guide to the recommended procedures required to gather accurate data for use in the calculation of the lightweight characteristics. A complete understanding and documentation of proper procedures to conduct a stability test is paramount to confirm that the results gathered during the test can be examined for accuracy, especially by third parties subsequently reviewing the data.

This guide is recommended to be used for all small boat capable of being lifted safely with forward and aft pick points capable of supporting additional inclining weights to be used for the stability test or with suitable sling arrangements

The idea for this study was generated by reading reference 1*. In this publication, the author analyzes the basic principle of plating strength which may be applied to the design of framing systems. However, the important factors of, interior space utilization, weight and cost savings, producibility and maintenance, in general, are not considered or examined for the benefit of the ship designer.

The safety of a ship or boat from wind and wave forces is largely a function of size. Properly designed and loaded ships and boats resist the heeling forces of wind and waves, and this resistance, or righting capacity, can be calculated. The righting capacity of a large undamaged ship can exceed the overturning forces of wind and waves of hurricane force.  As size diminishes, there comes a point where wind and wave forces CM eve-helm even a well designed, properly loaded, and capably operated boat. This survey was undertaken to benchmark the safety limits for small fishing vessels.