SAWE RP M-11, 2016: Mass Properties Requirements for Marine Vehicle Design Software

Scope

A major function within the discipline of mass properties engineering for the marine industry is the determination of weights and centers of gravity from the engineering products which define the ship or marine platform.  Originally consisting primarily of paper drawings, these manually prepared products have, over the past several decades, evolved into two-dimensional (2-D) Computer-aided Design (CAD) systems of the 1970’s and 80’s, and ultimately the advanced three-dimensional (3-D) CAD/ CAE (Computer-Aided Engineering) product modeling systems of today.  Such systems have now become widely accepted, well-proven staples in the design of ships and other marine vehicles.  The mass properties engineering discipline is currently evolving in order to take maximum advantage of the latest technology.  Many advantages offered by advanced design tools can make the calculation of mass properties characteristics simpler, faster, easier, and more accurate if certain specific functional capabilities are built into the software tool.  But, while the 3-D CAD/CAE systems of today have tremendous capability for the designer, the features that are intended to support the design and engineering functions are not necessarily the same as those required by the mass properties engineer. Therefore, the basic 3-D modeling system offered by most design tool developers must typically be customized to suit the requirements of the mass properties discipline.  Customization may also be required because the tool may have been developed for another industry such as aerospace or land vehicles rather than the marine field. The need for customization is also often driven by the fact that the customization of a design tool for one marine industry user is seldom available to a marine user.

Purpose

This Recommended Practice is intended to identify and define the basic mass properties features and functions that are most common to marine industry users.  This document is not intended to eliminate the need for design tool customization by an individual shipyard or ship designer to support its own unique processes, procedures, or preferences.  As this document addresses the basic, or core, capabilities required by the mass properties engineering discipline, it should leave the prospective new user of a design tool more time to concentrate on their unique features rather than spend valuable time and effort to define core functionality related to weight and center of gravity determinations. The requirements identified herein are the basic requirements and are not to be confused with how such requirements are to be satisfied.  Typically, the next step in the process is to define how the requirement is to be met, but in most cases this is dependent on the specific preferences and practices of the shipyard and the specific capabilities of the software selected.

The Marine Systems Committee of the SAWE Standards and Practices Committee has recognized the criticality of having consensus mass properties functionality for design tools and its contribution to saving time and manhours in the adoption of a new design tool.  Such benefits can be realized by both the user and the developer of such systems for the marine industry.