Overview
ISO 5572:1987 defines standardized conventions for the numbering of equipment and structural elements in ships. Intended mainly for conventional mono-hull merchant ships, the standard prescribes how to assign reference numbers to stations, waterlines, structural frames, transverse bulkheads, decks, compartments (holds, tween-decks, tanks), hatchways, masts and cargo‑handling equipment for use in computer programs, drawings and ship documentation. It was developed by ISO/TC 8 (Shipbuilding and marine structures).
Key topics and technical requirements
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Reference stations / frames
- Frames used for calculation and plotting are numbered with a decimal system (base 10 or 100 intervals).
- The frame at or immediately forward of the aft perpendicular is designated frame 0; frames forward are positive, aft are negative.
- Primary frames are integer or decimal values (examples in the standard: 5.0, 50.0); intermediate frames may use fractional decimals (e.g., 9.75).
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Waterlines
- Waterlines are identified by their height (in metres) above the zero waterline; non‑dimensional presentations use fractional designations referenced to the theoretical draft.
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Transverse bulkheads and partial members
- Bulkheads are numbered by successive integers starting from the most aft bulkhead designated 1. Partial bulkheads and partial frames that do not encircle the section are included within the construction frame numbering system.
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Decks and superstructure
- Main deck = Deck 1; lower decks numbered 2, 3… Superstructure decks use an alphabetic prefix (typically S1, S2…), with recommended readable abbreviations for special decks.
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Compartments (holds, tween‑decks, tanks)
- Compartment codes use up to eight characters in four fields: field 1 (integer 1–99 for rank), field 2 (A/B/T for centre/port/starboard), field 3 (location qualifiers like SUP/INF/INT/EXT/AVT/ARR), and an optional field 4 for function/service (e.g., RF for refrigerated, ED for fresh water).
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Hatchways, masts, cargo‑handling equipment
- Hatchways follow the same compartment numbering (hatch = same field‑1 number as its hold).
- Masts and cargo gear (winches, cranes) are numbered fore to aft; winches share the mast number they belong to.
Applications and users
ISO 5572 is used to ensure consistent identification across:
- Ship design and naval architecture drawings and CAD/CAM systems
- Shipyard production, fabrication and assembly documentation
- Classification societies, marine surveyors and regulatory reporting
- Ship management, maintenance planning and asset databases
- Software developers building naval architecture, stability and logistics applications
Related standards
ISO 5572 complements other ISO and industry standards on shipbuilding and marine structures (developed under ISO/TC 8) and is intended as a harmonized reference for numbering conventions used in computer programs and technical documentation.
Keywords: ISO 5572, shipbuilding numbering, numbering of equipment, marine structures, reference stations, waterlines, structural frames, compartments, decks, hatchways, masts, cargo-handling.