ASTM F1321-21 PDF

Full title and description

Standard Guide for Conducting a Stability Test (Lightweight Survey and Inclining Experiment) to Determine the Light Ship Displacement and Centers of Gravity of a Vessel — a 2021 ASTM guide describing procedures for lightweight surveys and inclining experiments used to establish a vessel's light ship displacement and centers of gravity (longitudinal, vertical and, where applicable, transverse).

Abstract

This guide explains the two-part stability test (a lightweight survey and an inclining experiment) used to determine a conventional hull-form vessel’s light ship characteristics: displacement, longitudinal center of gravity (LCG) and vertical center of gravity (KG). It addresses test planning, equipment, execution, calculations, reporting and limitations (for example trim and heel limits) and notes exceptions for special vessel types.

General information

• Status: Active standard (current edition published 2021).
• Publication date: 2021 (document last updated/active edition dated May 27, 2021).
• Publisher: ASTM International.
• ICS / categories: Ships and marine technology — general standards related to shipbuilding and marine structures (ICS 47.020.01).
• Edition / version: F1321-21 (2021 edition).
• Number of pages: 29 pages.

Scope

This guide covers determination of a vessel’s light ship characteristics for traditional hull-formed ships through a lightweight survey combined with an inclining experiment. It describes limits and assumptions (for example trim or heel bounds when using pre-defined hydrostatic characteristics), reporting units (inch-pound units by default) and notes vessel types and conditions where additional or different considerations apply (for example MODUs, asymmetrical vessels, semi-submersibles and other non-conventional platforms are treated separately or excluded).

Key topics and requirements

• Definitions and objectives of lightweight surveys and inclining experiments.
• Pre-test planning: condition of vessel, required preparations, calibration and equipment checks.
• Measurement procedures for small deliberate weight moves and draft/trim observations.
• Data reduction and calculation methods for displacement, LCG, KG and (where needed) TCG.
• Limits, assumptions and reporting requirements (units, uncertainty considerations, and deviations from ideal conditions).
• Special considerations for asymmetrical vessels and mobile offshore units.

Typical use and users

Used by naval architects, marine surveyors, shipbuilders, ship owners/operators, classification societies and marine consultants to establish or verify a vessel’s light ship displacement and centers of gravity after construction, conversion or major outfitting changes. It is also used to support stability book preparation, regulatory compliance and safety assessments.

Related standards

Related procedures and references include prior and subsequent editions of ASTM F1321, other ASTM and ISO standards covering ship stability, hydrostatic calculations and measurement practice, and classification-society guidance on inclining experiments and lightweight surveys. Historical edition and revision information for F1321 (including the 2014 and earlier editions) is available in the document history.

Keywords

inclining experiment, lightweight survey, stability test, light ship displacement, longitudinal center of gravity (LCG), vertical center of gravity (KG), transverse center of gravity (TCG), vessel stability, marine survey.

FAQ

Q: What is this standard?

A: ASTM F1321-21 is a standard guide that describes how to perform a stability test composed of a lightweight survey and an inclining experiment to determine a vessel’s light ship displacement and centers of gravity.

Q: What does it cover?

A: It covers test planning, required preparations, measurement procedures for weight shifts and draft/trim observations, data reduction and calculations to report displacement, LCG and KG (and where applicable TCG), plus limitations and reporting conventions.

Q: Who typically uses it?

A: Naval architects, marine surveyors, shipyards, ship owners/operators, classification societies and consultants performing or specifying inclining experiments and lightweight surveys.

Q: Is it current or superseded?

A: The F1321-21 edition is the current active edition (2021). Historical editions (for example 2014 and earlier) are documented in the revision history; users should check for any amendments or later revisions before relying on a specific clause.

Q: Is it part of a series?

A: It is part of ASTM’s maritime/shipbuilding guidance under Committee F25 and is related to other ASTM standards for shipboard measurements, hydrostatics and marine practices (listed under ICS 47.020.01).

Q: What are the key keywords?

A: inclining experiment, lightweight survey, displacement, LCG, KG, stability test, vessel stability, marine survey.