3715. Negligible Weight Quantification for Surface Ship Weight Surveys

Paper

Abstract

Shipboard weight surveys are routinely performed for surface vessels across the spectrum of marine industries from small pleasure craft to large surface combatants. These surveys are typically part of a vessel’s stability test (weight survey & inclining experiment) usually required as part of the vessel’s delivery/acceptance or during its service life to confirm the safety of the vessel and/or crew/passengers has not been compromised from post-delivery modifications or inevitable weight & KG growth. These stability tests may take a few days to a few weeks, with a large portion of the effort attributed to the weight survey itself. Further, a large portion of the survey consists of inventorying smaller items which typically constitute a relatively small portion of the overall weight nor may have any appreciable impact to the overall results of the stability test.To date (to the author’s knowledge), no official guidance or recommendation(s) exists on what or how to quantify as negligible weight(s) for the purposes of a weight survey. This guidance, if available, may reduce the time required for survey and save considerable time and resources without appreciably changing the end result and/or conclusion.With limited availability/diversity of actual ship survey data, the analysis will focus on the required precision of the stability test based on accepted requirements documentation. This analysis will consider the size of the vessel which directly impacts the design’s sensitivity to weight, as well as the practicalities associated with the existing practices of shipboard surveys such as availability of the vessel or qualified personnel. In addition, industry guidance on human engineering design will be used to establish ‘rules of thumb’ for determining item weights and/or their potential impact to the results to aid in shipboard surveys.