Overview
ISO 20672:2022 - Ships and marine technology - Rate of turn indicators - specifies construction, performance requirements, test methods and required test results for rate of turn indicators mandated by SOLAS (Reg. 19, ch. V). The second edition (2022) updates the 2007 standard and aligns requirements with IMO Resolution A.526(13), while referencing related IMO and IEC documents. This standard takes precedence where it differs from IEC 60945.
Key topics and requirements
- Scope and purpose: Defines requirements for instruments that display ship yaw rate in degrees per minute (to port and starboard).
- Indication and display:
- Centre-zero analogue-type indicator (preferably circular); digital/alphanumeric displays allowed as additional features.
- Zero uppermost for circular scales; port left, starboard right; clear indication if rate exceeds full scale.
- Minimum scale length: 120 mm; sensitivity: 1°/min = ≥4 mm movement.
- Range scales:
- Minimum linear range: ±30°/min (marked every 1°; figures every 10°).
- Optional ranges: ±120°/min and ±300°/min with proportionate markings.
- Performance and accuracy:
- Indicated rate must not deviate by more than 0.5°/min + 5% of indicated rate (includes earth rate).
- Must meet accuracy under periodic roll/pitch motions and at ship speeds up to 30 knots.
- Damping time constant adjustable from 0 to ≥10 s.
- Operational requirements:
- Ready for operation within 4 minutes of power-up.
- Must allow operator verification of correct operation and not degrade connected equipment.
- Testing and environmental:
- Accuracy, operation, insulation and environmental tests specified; environmental tests generally per IEC 60945.
- Insulation/high-voltage tests may apply IEC 60092-504.
- Alerts and interfaces:
- If capable of raising alerts, comply with MSC.302(87) and IEC 62923-1/-2.
- Interface options reference IEC 61162-1/2/450 and presentation displays reference IEC 62288.
- Marking & documentation: Manufacturer ID, model/type, serial number, and minimum safe distance from a magnetic compass must be marked; adequate documentation required.
Applications and who uses it
- Shipbuilders and naval architects - integrate compliant rate-of-turn indicators into bridge design.
- Marine instrumentation manufacturers - design, type-test and certify products to ISO 20672:2022.
- Flag administrations, classification societies and certification bodies - use the standard for type approval and statutory compliance with SOLAS.
- Ship operators, bridge teams and system integrators - procure, install and maintain compliant navigation equipment.
- Test laboratories - perform accuracy, environmental and interface testing per the standard.
Related standards and references
Keywords: ISO 20672:2022, rate of turn indicators, ships, marine technology, SOLAS, IMO A.526(13), IEC 60945, bridge navigation equipment, maritime instrumentation.
