ISO 484-1:2015

Overview

ISO 484-1:2015 - Shipbuilding - Ship screw propellers - Manufacturing tolerances - Part 1: Propellers of diameter greater than 2,50 m defines the manufacturing and inspection tolerances for large ship screw propellers (diameter > 2.50 m). The standard specifies measurement methods, accuracy classes, and permissible tolerances for pitch, blade thickness, radius, blade form, rake and axial position, surface finish, static balancing and measuring equipment. It also notes that certain deviations can be accepted by agreement between the manufacturer, designer and customer.

Key topics and technical requirements

• Scope: Applies to monobloc, built-up and controllable-pitch propellers with diameter > 2.50 m.
• Accuracy classes: Four classes - S (very high), I (high), II (medium), III (wide) - guide tolerance selection.
• Pitch measurement methods:
  • Use of marking gauges
  • Graduated ring method
  • Coordinate measuring machine (CMM) using Cartesian or polar coordinates
    The standard defines local, mean-per-radius, per-blade and overall propeller pitch tolerances (expressed as percentages of design pitch with minimum mm limits).
• Blade thickness & section checking: Thickness measured on cylindrical sections using callipers or plotted profiles; plus/minus tolerances given by accuracy class. Form checks for Classes S and I include templates or equivalent devices; CNC-machined blades may waive further checks by agreement.
• Radius and geometric tolerances: Tolerances on extreme propeller radius are given as percent of radius; tighter tolerances recommended for ducted propellers.
• Blade form continuity and templates: Requirements for template design, overlap and permitted deviations are specified to ensure camber and edge accuracy.
• Other requirements: Rake and axial position tolerances, surface finish per ISO 1302 (normative reference), static balancing and recommended measuring equipment are covered.

Practical applications and users

ISO 484-1:2015 is intended for:

• Propeller manufacturers and CNC machine shops for production and quality control.
• Shipyards and marine contractors for acceptance testing and installation checks.
• Naval architects and propeller designers to specify achievable tolerances and inspection points.
• Classification societies and surveyors who verify compliance with contractual or regulatory requirements.
• Metrology and QA engineers who set up measurement procedures (CMM, templates, rings, callipers).

Use cases include final inspection of large propellers, contract specifications for newbuilds or repairs, and defining acceptance criteria when compensating pitch errors (with customer agreement).

Related standards

• ISO 484-2 (Part 2) - Propellers of diameter between 0,80 m and 2,50 m (companion document).
• ISO 1302 - Geometrical Product Specifications (GPS) - Indication of surface texture (normative reference used in ISO 484-1).

Keywords: ISO 484-1:2015, ship screw propellers, manufacturing tolerances, propeller pitch measurement, blade thickness, accuracy classes, propeller inspection, shipbuilding standards.