ISO 13643-3:2017

Overview - ISO 13643-3:2017 (Yaw stability and steering)

ISO 13643-3:2017, part of the ISO 13643 series, defines symbols and terms and provides guidelines for conducting manoeuvring tests that give evidence about the yaw stability and steering of surface ships, submarines and scaled models. Designed to be read together with ISO 13643‑1, this part standardizes test types, test‑related physical quantities and the analysis and presentation of results so that yaw‑stability and steering characteristics can be compared and documented consistently.

Key technical topics and requirements

• Scope and terminology
  • Defines specialised terms (e.g., pull‑out test, direct spiral, reverse spiral, weave, astern and sine tests) and manoeuvring device definitions (rudder, azimuthing thruster, hydroplane, cycloidal propeller, etc.).
• Test types covered
  • Pull‑out test - quick determination of yaw stability vs speed.
  • Direct spiral test (Dieudonné) - evaluates yaw stability and turning under constant manoeuvring settings.
  • Reverse spiral test (Bech) - assesses turning and stability using constant yaw rates.
  • Weave test - determines potential yaw instability amplitude.
  • Astern tests (direct astern and astern zig‑zag) - evaluate course‑keeping while making way astern and manoeuvring device efficiency.
  • Sine test - used to characterise turning and yaw‑checking ability and for autopilot tuning.
• Test conditions and quantities
  • Specifies general test conditions, test‑related physical quantities and units (references ISO 80000‑1 and ISO 80000‑3).
  • Provides guidance on data analysis, presentation of results and formal designation of tests for clear reporting.
• Analysis and reporting
  • Guidance on extracting metrics (heading change, rates of turn, device angles, time intervals, track transfer) and presenting them in a standardized way for interpretation and comparison.

Practical applications and who uses this standard

ISO 13643‑3:2017 is practical for:

• Naval architects and ship designers evaluating directional stability during design and sea trials.
• Model basin and towing tank engineers conducting scaled manoeuvring tests.
• Classification societies and regulatory bodies assessing compliance and sea‑trial data.
• Shipyards and ship operators validating steering performance and manoeuvrability.
• Autopilot and control system engineers using sine and spiral tests to tune control laws.
• Submarine designers applying equivalent manoeuvring‑device definitions (e.g., X‑planes).

Using these standardized test methods helps ensure repeatable, comparable, and auditable evidence of steering behaviour and yaw stability across projects.

Related standards

• ISO 13643‑1:2017 - General concepts, quantities and test conditions (mandatory companion)
• ISO 13643‑5:2017 - Submarine specials
• ISO 80000‑1 and ISO 80000‑3 - Quantities and units

Keywords: ISO 13643-3:2017, yaw stability, steering, manoeuvring tests, ships, submarines, pull-out test, Dieudonné, Bech, weave test, sine test, manoeuvring devices, autopilot tuning.