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GB/T 20895.1-2025Small craft - Stability and buoyancy assessment and categorization - Part 1: Non-sailing boats of hull length greater than or equal to 6 m (English PDF)

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Issued by

State Administration for Market Regulation, National Standardization Administration

Level / Type

National · Recommended

Issue date

August 29, 2025

Implementation date

March 1, 2026

Scope

GB/T 20895.1-2025 (Small craft - Stability and buoyancy assessment and categorization - Part 1: Non-sailing boats of hull length greater than or equal to 6 m) is available as an English-translated PDF.

GB/T 20895.1-2025 — This document describes the method for assessing the stability and buoyancy of intact (i.e. undamaged) non-sail craft of not less than 6 m in length.

Method for determining the buoyancy of a boat susceptible to flooding and sinking. Use this document to assess stability and buoyancy and assign each boat a design category appropriate to its design load and maximum load.

(A, B, C or D). This document is applicable to the assessment and evaluation of the stability and buoyancy of boats with a length of 6m to 24m, which are mainly propelled by human or mechanical power.

This document is also applicable to the assessment and classification of the stability and buoyancy of boats with a hull length of less than 6 m, if they do not meet the requirements of ISO 12217-3 and having a deck and a concave body for rapid drainage in accordance with the requirements of ISO 11812.

This document includes an assessment of the upside-down susceptibility of habitable multihull craft, the definition of feasible means of escape, and requirements for upside-down buoyancy.

This document does not include. --- Inflatable boats and rigid inflatable boats covered by ISO 6185, except for references in ISO 6185 to specific clauses of ISO 12217; --- Jet skis and other similar power boats covered by ISO 13590; ---Pontoons and pedal boats; ---Sailboat surfboard; ---Surfboards, including powered surfboards; --- Hydrofoils and hovercraft when not sailing in displacement mode; ---Submersible.

Note. Displacement mode means the boat is supported by hydrostatic forces only. This document does not consider or assess the effects of towing, fishing, dredging or lifting operations on stability; these will need to be considered separately (if applicable). use).

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Document preview — GB/T 20895.1-2025

National Standard of the People's Republic of China

ICS
47.080
Classification
U 18
Replacing
GB/T 20895.1-2007

Issued by: State Administration for Market Regulation, National Standardization Administration

Contents

  • Preface
  • Introduction
  • 1 Scope
  • 2 Normative references
  • 3 Terms and Definitions
  • 3.1 Basic terminology
  • 3.2 Sinking and water ingress
  • 3.3 Principal Dimensions, Areas, and Angles
  • 3.4 State, mass and volume
  • 3.5 Other terms and definitions
  • 4 Symbol
  • 5 Step
  • 5.1 Maximum load
  • 5.2 Sailing or non-sailing boats
  • 5.3 Tests and calculations to be performed
  • 5.4 Changes in input parameters
  • 6 Tests, calculations and requirements
  • 6.1 Sinking and Water Intake
  • 6.2 Offset load test
  • 6.3 Wind and Wave Resistance 17
  • 6.4 Wind-induced heel
  • 6.5 Concave body size
  • 6.6 Habitable multihull craft
  • 6.7 Motor sailing boat
  • 6.8 Buoyancy requirements
  • 6.9 Water Monitoring and Drainage
  • 7 Applications
  • 7.1 Dimensioning Design Category
  • 7.2 Meaning of design categories
  • Appendix A (Normative) Complete calculation method for required submerged water height
  • Appendix B (Normative) Offset Load Test Method
  • B.1 Purpose
  • B.2 Determination method
  • B.3 Method
  • B.4 Application of physical tests
  • B.5 Application of calculations
  • Appendix C (Normative) Calculation Method of Sinking Water Intake Angle
  • C.1 Choice of method
  • C.2 Theoretical Calculation
  • C.3 Approximate method for calculating sinking angles less than or equal to 60°
  • Appendix D (Normative) Methods for measuring freeboard margin
  • D.1 Definition
  • D.2 Example
  • Appendix E (Normative) Method for determining the restoring torque curve
  • E.1 Method
  • E.2 Mass and center of gravity
  • E.3 Determine by precise calculation
  • E.4 Determined by testing
  • Appendix F (Normative) Floating Test Method
  • F.1 General requirements
  • F.2 Test conditions
  • F.3 Water-filled stability test
  • F.4 Buoyancy test under water
  • Appendix G (Normative) Buoyant Materials and Equipment
  • G.1 Requirement
  • G.2 Test
  • Appendix H (Normative) Contents of the Owner's Manual
  • H.1 General Content
  • H.2 Specific content
  • Appendix I (Informative) Summary of requirements
  • Appendix J (Informative) Worksheet
  • Appendix K (Informative) Description of Concave Body Retention Water Level
  • Reference

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.

This document is Part 1 of GB/T 20895 "Assessment and classification of stability and buoyancy of small craft". GB/T 20895 has been published.

The following parts.

--- Part 1: Non-sail boats with a hull length of not less than 6 m;

--- Part 2: Sailing boats with a hull length of not less than 6 m;

--- Part 3: Boats with a hull length of less than 6 m.

This document replaces GB/T 20895.1-2007 "Assessment and classification of stability and buoyancy of small craft - Part 1.hull length not less than Compared with GB/T 20895.1-2007, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

--- Added the definitions of fully enclosed boats, partially protected boats and habitable boats (see 3.1.6, 3.1.7 and 3.1.8);

--- Added the definition of nominal sail area (see 3.3.8);

--- Changed the definition of empty boat state (see 3.4.1, 2007 edition 3.4.1), added light boat state, maximum load, maximum load state Definitions of full load arrival state and fully loaded arrival state (see 3.4.2, 3.4.4, 3.4.5 and 3.4.6);

--- Added the definitions of basic safety equipment, concave water retention level, standard equipment, and navigation (see 3.5.5, 3.5.9, 3.5.12, 3.5.14);

--- Added requirements for sinking water inlet openings (see 6.1.1.3);

--- Changed the offset load test (see 6.2, 6.2 of the 2007 edition);

--- Changed the requirements for wind-induced heel (see 6.4.3, 6.4 of the 2007 edition);

--- Added the requirements for concave body dimensions (see 6.5);

--- Added tests, calculations and requirements for habitable multi-hull craft (see 6.6);

--- Added tests, calculations and requirements for power sailing boats (see 6.7);

--- Changed the buoyancy requirements (see 6.8, 6.5 of the 2007 edition);

--- Added provisions for water monitoring and drainage (see 6.9);

--- Changed the complete method of required sinking height (see Appendix A, Appendix A of the 2007 edition);

--- Changed the offset load test method (see Appendix B, Appendix B of the 2007 edition);

--- Changed the method for determining the restoring torque curve (see Appendix E, Appendix D of the 2007 edition);

--- Changed the contents of the Owner's Manual (see Appendix H, Appendix G of the 2007 edition).

This document is equivalent to ISO 12217-1:2022 "Assessment and classification of stability and buoyancy of small craft - Part 1: Craft of not less than hull length" 6m non-sailing boat.

Introduction

GB/T 20895 "Assessment and classification of stability and buoyancy of small boats" provides the assessment and classification of stability and buoyancy of small boats, which consists of three parts.

constitute.

--- Part 1: Non-sail boats with a hull length of not less than 6 m. The purpose is to give the stability of non-sail boats with a hull length of not less than 6 m.

Evaluation and classification of stability and buoyancy, using this part to assess stability and buoyancy, assigning a value to each boat that matches its design load and maximum Design category (A, B, C or D) appropriate for large loads.

--- Part 2: Sailboats with a hull length of not less than 6 m. The purpose is to give the stability and buoyancy of sailboats with a hull length of not less than 6 m.

This part is used to evaluate the stability and buoyancy of each boat and to assign a load rating corresponding to its design load and maximum load.

The design category (A, B, C or D) is appropriate for the load.

--- Part 3: Boats with a hull length of less than 6 m. The purpose is to provide an assessment of the stability and buoyancy of boats with a hull length of less than 6 m this part is used to evaluate the stability and buoyancy of each boat and to assign a load rating appropriate to its design load and maximum load.

Design category (C or D).

Assessment and classification of stability and buoyancy of small boats Part 1: Non-sailboats with a hull length of not less than 6m

NOTE. Compliance with the requirements of this document does not guarantee that the boat is 100% safe or that there is no risk of capsizing or sinking.

Important Note. The electronic version of this document contains color content, which is very useful for correct understanding of the content of the document.

It is recommended that you print this document on a color printer.

1 Scope

This document describes the method for assessing the stability and buoyancy of intact (i.e. undamaged) non-sail craft of not less than 6 m in length.

Method for determining the buoyancy of a boat susceptible to flooding and sinking.

Use this document to assess stability and buoyancy and assign each boat a design category appropriate to its design load and maximum load.

(A, B, C or D).

This document is applicable to the assessment and evaluation of the stability and buoyancy of boats with a length of 6m to 24m, which are mainly propelled by human or mechanical power.

This document is also applicable to the assessment and classification of the stability and buoyancy of boats with a hull length of less than 6 m, if they do not meet the requirements of ISO 12217-3 and having a deck and a concave body for rapid drainage in accordance with the requirements of ISO 11812.

This document includes an assessment of the upside-down susceptibility of habitable multihull craft, the definition of feasible means of escape, and requirements for upside-down buoyancy.

This document does not include.

--- Inflatable boats and rigid inflatable boats covered by ISO 6185, except for references in ISO 6185 to specific clauses of ISO 12217;

--- Jet skis and other similar power boats covered by ISO 13590;

---Pontoons and pedal boats;

---Sailboat surfboard;

---Surfboards, including powered surfboards;

--- Hydrofoils and hovercraft when not sailing in displacement mode;

---Submersible.

Note. Displacement mode means the boat is supported by hydrostatic forces only.

This document does not consider or assess the effects of towing, fishing, dredging or lifting operations on stability; these will need to be considered separately (if applicable).

use).

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

GB/T 2893.1-2013 Graphical symbols, safety colors and safety signs Part 1: Design principles of safety signs and safety markings Then (ISO 3864-1:2011, MOD) Note. There is no technical difference between the referenced content of GB/T 2893.1-2013 and the referenced content of ISO 3864-1:2011 GB/T 8810-2005 Rigid cellular plastics - Determination of water absorption (ISO 2896:2001, MOD) Note. There is no technical difference between the referenced content of GB/T 8810-2005 and the referenced content of ISO 2896:2001 GB/T 19315-2025 Maximum loading capacity of small craft (ISO 14946:2021, IDT)

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 62 pages — is available in the English PDF.

Referenced standards

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