Overview
ISO 13776:2020 - Ships and marine technology - Ship's mooring and towing fittings - Pedestal fairleads specifies the nominal sizes, dimensions, materials, construction, manufacturing, inspection and marking requirements for pedestal fairleads used to lead a ship’s mooring rope. The standard defines preferred roller diameters, dimensional tables and strength assessment principles to ensure safe, durable pedestal fairleads for shipboard mooring and towing operations.
Key topics and technical requirements
- Nominal sizes and dimensions: Pedestal fairleads are defined by the roller outside diameter (D). Nominal roller sizes in ISO 13776:2020 are 150, 200, 250, 300, 350, 400, 450 and 500 mm. Detailed dimensional tables and assembly figures are provided.
- Materials: Manufacture from weldable steel plates with a minimum yield point of 235 N/mm².
- Manufacturing & inspection:
- All surfaces, including welds, must be free from visible flaws.
- Surfaces contacting ropes must be free from roughness or irregularities that could abrade mooring ropes.
- External anti‑corrosion protective coating is required.
- Strength assessment (Annex A):
- Design evaluated using simple beam theory.
- Load cases include rope deflection through the throat of the roller (180°) and other deflection angles.
- Allowable stresses: bending limited to 85% of yield stress, shear limited to 60% of yield stress.
- Wear and corrosion allowances are incorporated in the stress criteria.
- Marking & SWL (Safe Working Load):
- SWL must be noted in the ship’s towing and mooring plan (see IMO MSC/Circ.1175).
- The actual on‑board SWL must consider under‑deck reinforcement and shall not exceed the SWL indicated by the standard.
- Pedestal fairleads must be clearly marked with SWL in tonnes (e.g., “SWL XXX t”) by weld bead or equivalent, placed so it is not obscured during operation.
- References: ISO 13755 (steel rollers) and IMO guidance are cited; dimensional and SWL tables are included for design and reference.
Applications and users
ISO 13776:2020 is used for:
- Shipbuilders and shipyards specifying and installing mooring fittings.
- Manufacturers of mooring hardware and pedestal fairleads for design, fabrication and quality control.
- Naval architects and marine engineers for structural design and integration with deck reinforcement.
- Classification societies, port authorities and ship operators for inspection, certification and safe mooring procedures.
- Procurement teams preparing technical specifications and compliance documentation.
Related standards
- ISO 13755 - Steel rollers (used with pedestal fairleads)
- IMO MSC/Circ.1175 - Guidance on shipboard towing and mooring equipment
- Additional guidance: ISO 2408, IACS UR A2, OCIMF Mooring Equipment Guidelines (MEG4)
Keywords: ISO 13776:2020, pedestal fairleads, ship mooring fittings, SWL, mooring rope, marine technology, shipboard fittings.