Overview
EN ISO 5778:2000 (ISO 5778:1998) covers design, dimensions, materials and manufacture of small weathertight steel hatches for ships and marine technology. The standard establishes main dimensions, location and number of fittings, sealing details and quality requirements to ensure interchangeability and reliable weathertightness for hatches used for loading operations and access to storage compartments and dry cargo holds. It explicitly excludes use as tank access or escape hatches and notes conformity with statutory rules such as the International Convention on Load Lines (LLC66).
Key topics and technical requirements
- Nominal sizes: Standard nominal inside coaming dimensions include 630×630, 630×830, 830×630, 830×830, 1030×1030 and 1330×1330 mm.
- Coaming and cover geometry: Upper coaming dimensions are defined relative to nominal sizes; cover plate sizes are slightly larger (e.g. 674×674 mm for a 630×630 nominal hatch). Edges should be rounded or chamfered to protect seals.
- Hatch seal: Resilient seal cross-section is 45×20 mm. Initial compression allowance is 2 mm; a depth stop must prevent compression exceeding 4 mm. Seal must be bonded and retained by a bar.
- Fittings: Two hinges per hatch with oval holes to permit seal compression; closing devices use toggle bolts with wing nuts sized for one-man tightening (threads per ISO 262). Provision for securing open covers and counterbalance weights is recommended.
- Materials and strength: Coamings, covers and primary fittings: weldable steel with minimum tensile strength 340 N/mm² (shipbuilding quality). Toggle bolts: corrosion-resistant with minimum 350 N/mm². Seal material must resist marine conditions and retain sealing/resealing performance.
- Manufacture and finish: Components must be free from distortion and exposed rough edges; surfaces treated (blast-cleaned or equivalent) and primed to inhibit corrosion.
- Weathertightness testing: Installed hatches must pass a hose test or equivalent to the satisfaction of the regulatory authority.
- Load Lines and stiffening: Generally conforms with LLC66; for application in certain positions (position 1 and 2) additional stiffening of covers may be required (Regulation 16(2) LLC66).
Applications and users
- Practical uses: loading operations, access to storage compartments and dry cargo holds on merchant and work vessels.
- Primary users: shipbuilders, naval architects, hatch manufacturers, shipyards, marine equipment suppliers, classification societies and regulatory inspectors responsible for compliance and installation.
- Benefits: ensures interchangeability, predictable sealing performance, and clearer procurement/specification language for marine hatch components.
Related standards
- ISO 262 (general-purpose metric screw threads) - referenced for wing nut and toggle-bolt threads.
- International Convention on Load Lines 1966 (LLC66) - compliance and stiffening requirements.
Designation example: Hatch ISO 5778 - 830 × 630
Keywords: EN ISO 5778:2000, small weathertight steel hatches, hatch dimensions, hatch seal, weathertightness, ships and marine technology, ISO 5778.