ASTM F 1321 : 2013

1.1This guide covers the determination of a vessel's light ship characteristics. In this standard, a vessel is a traditional hull-formed vessel. The stability test can be considered to be two separate tasks; the lightweight survey and the inclining experiment. The stability test is required for most vessels upon their completion and after major conversions. It is normally conducted inshore in calm weather conditions and usually requires the vessel be taken out of service to prepare for and conduct the stability test. The three light ship characteristics determined from the stability test for conventional (symmetrical) ships are displacement (“displ”), longitudinal center of gravity (“LCG”), and the vertical center of gravity (“KG”). The transverse center of gravity (“TCG”) may also be determined for mobile offshore drilling units (MODUs) and other vessels which are asymmetrical about the centerline or whose internal arrangement or outfitting is such that an inherent list may develop from off-center weight. Because of their nature, other special considerations not specifically addressed in this guide may be necessary for some MODUs. This standard is not applicable to vessels such as a TLP, semi-submersibles, RHIB, and so on.

1.2The limitations of 1 % trim or 4 % heel and so on applies if one is using the traditional pre-defined hydrostatic characteristics. This is due to the drastic change of waterplane area. If one is using calculating hydrostatic characteristics at each move, such as utilizing a computer program, then the limitations are not applicable.

1.3This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.