ISO 12217-2:2022
Small craft — Stability and buoyancy assessment and categorization — Part 2: Sailing boats of hull length greater than or equal to 6 m
This document specifies methods for evaluating the stability and buoyancy of intact (i.e. undamaged) boats. The flotation characteristics of boats susceptible to swamping are also encompassed.
The evaluation of stability and buoyancy properties using this document will enable the boat to be assigned to a design category (A, B, C or D) appropriate to its design and maximum load.
This document is principally applicable to boats propelled primarily by sail (even if fitted with an auxiliary engine) of 6 m up to and including 24 m hull length. However, it can also be applied to boats less than 6 m if they are habitable multihulls or can be applied if they do not attain the desired design category specified in ISO 12217‑3 and they are decked and have quick-draining recesses which comply with ISO 11812.
In relation to habitable multihulls, this document includes assessment of susceptibility to inversion, definition of viable means of escape and requirements for inverted flotation.
This document excludes:
— inflatable and rigid-inflatable boats covered by the ISO 6185 series, except for references made in the ISO 6185 series to specific clauses of the
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Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
3.1 Primary
3.2 Hazards
3.3 Downflooding
3.4 Dimensions, areas and angles
3.5 Condition, mass and volume
3.6 Other terms and definitions
4 Symbols
5 Procedure
5.1 Maximum load
5.2 Sailing or non-sailing
5.3 Tests, calculations and requirements to be applied
5.4 Variation in input parameters
6 Requirements for monohull boats
6.1 Requirements to be applied
6.2 Downflooding
6.2.1 Downflooding openings
6.2.2 Downflooding height
6.2.3 Downflooding angle
6.3 Recess size
6.3.1 Application
6.3.2 Simplified methods
6.3.3 Direct calculation method
6.4 Minimum righting energy
6.5 Angle of vanishing stability
6.5.1 General
6.5.2 Normal requirement
6.5.3 Alternative requirement for design category B
6.6 Stability index (STIX)
6.6.1 Method
6.6.2 Dynamic stability factor (FDS)
6.6.3 Inversion recovery factor (FIR)
6.6.4 Knockdown recovery factor (FKR)
6.6.5 Displacement-length factor (FDL)
6.6.6 Beam-displacement factor (FBD)
6.6.7 Wind moment factor (FWM)
6.6.8 Downflooding factor (FDF)
6.6.9 Calculation of the stability index (STIX)
6.7 Knockdown-recovery test
6.8 Wind stiffness test
6.8.1 General
6.8.2 Practical test
6.8.3 Compliance by calculation
6.8.4 Requirements
6.9 Flotation requirements
6.10 Capsize-recovery test
6.11 Detection and removal of water
7 Requirements for catamarans, trimarans and form-stable monohulls
7.1 Requirements to be applied
7.2 Downflooding openings
7.3 Downflooding height
7.4 Recess size
7.5 Stability information
7.6 Safety signs
7.7 Bare poles factor
7.8 Rolling in breaking waves
7.9 Pitchpoling
7.10 Diagonal stability
7.11 Habitable multihull boats
7.12 Buoyancy when inverted
7.13 Escape after inversion
8 Safety signs
9 Application
9.1 Deciding the design category
9.2 Meaning of the design categories
Annex A (normative) Full method for required downflooding height
Annex B (normative) Methods for calculating downflooding angle
Annex C (normative) Determining the curve of righting moments
Annex D (normative) Method for calculating reserve of buoyancy after inversion or swamping
Annex E (normative) Flotation material and elements
Annex F (normative) Information for the craft’s owner’s manual
Annex G (normative) Determination of safe wind speed information
Annex H (normative) Determination of longitudinal righting characteristics
Annex I (informative) Summary of requirements
Annex J (informative) Worksheets
Annex K (informative) Illustration of recess retention level
Bibliography
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Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
3.1 Primary
3.2 Hazards
3.3 Downflooding
3.4 Dimensions, areas and angles
3.5 Condition, mass and volume
3.6 Other terms and definitions
4 Symbols
5 Procedure
5.1 Maximum load
5.2 Sailing or non-sailing
5.3 Tests, calculations and requirements to be applied
5.4 Variation in input parameters
6 Requirements for monohull boats
6.1 Requirements to be applied
6.2 Downflooding
6.2.1 Downflooding openings
6.2.2 Downflooding height
6.2.3 Downflooding angle
6.3 Recess size
6.3.1 Application
6.3.2 Simplified methods
6.3.3 Direct calculation method
6.4 Minimum righting energy
6.5 Angle of vanishing stability
6.5.1 General
6.5.2 Normal requirement
6.5.3 Alternative requirement for design category B
6.6 Stability index (STIX)
6.6.1 Method
6.6.2 Dynamic stability factor (FDS)
6.6.3 Inversion recovery factor (FIR)
6.6.4 Knockdown recovery factor (FKR)
6.6.5 Displacement-length factor (FDL)
6.6.6 Beam-displacement factor (FBD)
6.6.7 Wind moment factor (FWM)
6.6.8 Downflooding factor (FDF)
6.6.9 Calculation of the stability index (STIX)
6.7 Knockdown-recovery test
6.8 Wind stiffness test
6.8.1 General
6.8.2 Practical test
6.8.3 Compliance by calculation
6.8.4 Requirements
6.9 Flotation requirements
6.10 Capsize-recovery test
6.11 Detection and removal of water
7 Requirements for catamarans, trimarans and form-stable monohulls
7.1 Requirements to be applied
7.2 Downflooding openings
7.3 Downflooding height
7.4 Recess size
7.5 Stability information
7.6 Safety signs
7.7 Bare poles factor
7.8 Rolling in breaking waves
7.9 Pitchpoling
7.10 Diagonal stability
7.11 Habitable multihull boats
7.12 Buoyancy when inverted
7.13 Escape after inversion
8 Safety signs
9 Application
9.1 Deciding the design category
9.2 Meaning of the design categories
Annex A (normative) Full method for required downflooding height
Annex B (normative) Methods for calculating downflooding angle
Annex C (normative) Determining the curve of righting moments
Annex D (normative) Method for calculating reserve of buoyancy after inversion or swamping
Annex E (normative) Flotation material and elements
Annex F (normative) Information for the craft’s owner’s manual
Annex G (normative) Determination of safe wind speed information
Annex H (normative) Determination of longitudinal righting characteristics
Annex I (informative) Summary of requirements
Annex J (informative) Worksheets
Annex K (informative) Illustration of recess retention level
Bibliography