Overview
ISO 6044:1985 specifies the main dimensions and basic material requirements for derrick boom heel fittings used in shipbuilding and marine structures. The standard defines dimensions for fork-type heel fittings and their associated bolts or pins to ensure interchangeability between suppliers and shipyards. It includes reference figures, a dimensional table (millimetres), and rules for designation of fittings for reference in drawings.
Key topics and requirements
- Scope: Main dimensions and materials for forks and associated bolts/pins of derrick boom heel fittings used in derricks and lifting arrangements on ships and marine structures.
- Nominal size: A numeric designation (no unit) derived from the permissible maximum thrust in the boom measured in kilonewtons (kN).
- Dimensions: Main fork and bolt/pin dimensions are specified by figures and a table (dimensions in millimetres). Figure notes clarify that the drawings indicate standardized dimensions but do not prescribe exact construction or shape.
- Diameter D: The fitting diameter equals the boom outside diameter or may be slightly larger depending on weld attachment form.
- Materials:
- Fork: steel to ISO 630, minimum grade Fe 360.
- Bolt/pin: steel to ISO 630, minimum grade Fe 430.
- If heat-treated quenched steels are required, material shall comply with ISO/R 683/1.
- Tolerances: Dimensional tolerances correspond to grade IT14 as given in ISO 286.
- Designation: Example format for reference (not for ordering): Heel fitting ISO 6044 - 10 (where 10 is nominal size).
- Notes: Type of bolt securing and final bolt/pin details are subject to national regulations and industry practice.
Applications and who uses it
ISO 6044 is directly relevant to:
- Shipbuilders and fabrication yards specifying derrick fittings for newbuilds and repairs
- Naval architects and marine engineers designing lifting arrangements and derricks
- Rigging designers and offshore lifting equipment suppliers seeking component interchangeability
- Classification societies, procurement teams, and surveyors verifying compliance with accepted dimensional and material practices
Using ISO 6044 helps ensure compatibility of heel fittings across different manufacturers, improves safety through clearer material specifications, and simplifies procurement and maintenance.
Related standards
- ISO 630 - Structural steels (material grades Fe 360, Fe 430)
- ISO 286 - ISO system of limits and fits (tolerance grades, including IT14)
- ISO/R 683/1 - Heat-treated steels, when quenched/tempered materials are required
- ISO 8147 - Shipbuilding vocabulary for derrick rigs and component parts
For design, manufacturing, and procurement, always confirm you are using the latest edition of ISO standards and consult national regulations for bolt securing and final construction details.
