Overview
EN ISO 11592-2:2021 - "Small craft - Determination of maximum propulsion power rating using manoeuvring speed - Part 2: Craft with a length of hull between 8 m and 24 m" is a CEN-adopted ISO standard that defines test procedures and documentation requirements for deriving the maximum propulsion power rating of engine-driven small craft with hull length (LH) from 8 m to 24 m. The standard applies to craft with a calculated Froude number (Fn) ≥ 1.1 and is published as EN ISO 11592-2:2021 for alignment with EU requirements.
Key topics and technical requirements
- Scope and applicability
- Applies to engine-driven craft LH between 8 m and 24 m with Fn ≥ 1.1.
- Exclusions: inflatable craft (ISO 6185-4), racing craft, and craft primarily not designed to be engine-driven.
- Does not set structural strength rules or guarantee stability in all sea/wind/wake/wave conditions.
- Test methods
- Quick turn test (Clause 6) - required for craft fitted with a steering wheel.
- Avoidance line test (Clause 7) - required for craft with steering means other than a wheel.
- Tests determine the maximum manoeuvring speed and feed into the maximum propulsion power rating.
- Test conditions and limits
- Tests are performed at no less than 85% of maximum craft speed (vmax) or the maximum test speed limit (vtmax), whichever is lower.
- vtmax is limited to 70 knots and is defined where vmax exceeds a length-dependent threshold.
- Documentation and labeling
- Owner’s manual must declare the maximum rated engine power (Clause 10).
- Warning labels (Clause 9) and engine power label (Clause 11) are required when tests indicate reduced manoeuvring capability.
- Test documentation and results are specified (Clause 8).
Applications and users
- Primary users:
- Boat manufacturers and OEMs validating recommended engine power.
- Naval architects and design engineers assessing manoeuvrability limits.
- Test laboratories and conformity assessment bodies performing propulsion/handling tests.
- Dealers and owners referencing declared maximum engine power and safety labeling.
- Regulatory bodies applying EU Directive 2013/53/EU (Annex ZA notes that compliance can provide presumption of conformity within the standard’s scope).
- Practical value:
- Ensures consistent, repeatable procedures to set safe maximum propulsion ratings tied to manoeuvring capability.
- Helps produce required owner documentation and safety labels for market access.
Related standards (if applicable)
- ISO 8666 - definitions for hull/waterline length and related dimensional data.
- ISO 8665 - engine power rating definitions (referenced for declared engine power).
- ISO 7010, ISO 10087 - safety sign and craft identification references.
- ISO 6185-4 - inflatable craft (not applicable under this part).
Keywords: EN ISO 11592-2:2021, small craft, maximum propulsion power, manoeuvring speed, Froude number, quick turn test, avoidance line test, owner’s manual, boat manufacturers, EU Directive 2013/53/EU.
