ISO 11812-2020 PDF

Full title and description

St ISO 11812-2020 — "Small craft — Watertight or quick-draining recesses and cockpits". This International Standard specifies performance requirements, design criteria and test/assessment methods for watertight and quick‑draining recesses and cockpits on small craft (hull length up to 24 m), covering watertightness, draining times and companionway sill heights.

Abstract

ISO 11812:2020 defines when a recess or cockpit is considered "watertight" or "quick‑draining", gives minimum sill heights and drain requirements, and provides calculation and test methods to verify draining time under gravity (pumping not considered). The standard applies to recesses located in elevated parts of the craft and does not replace stability/buoyancy standards.

General information

• Status: Published / Current (in force).
• Publication date: 31 July 2020 (ISO 11812:2020).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 47.080 — Small craft.
• Edition / version: Edition 2 (2020); amended by Amendment 1 (ISO 11812:2020/Amd 1:2024).
• Number of pages: 32 pages (main 2020 edition); Amendment 1 (2024) is 10 pages.

Scope

Specifies watertightness criteria, maximum draining time, minimum companionway sill heights and drainage design for watertight and quick‑draining recesses and cockpits on small craft with a load line length up to 24 m. The document covers recesses located in elevated parts of the craft, considers gravity drainage only (not pumped drainage) and is limited to normal operation (unattended‑recess scenarios are out of scope). It does not prescribe recess size, shape or exact location and does not itself address overall craft stability, which is covered by the ISO 12217 series.

Key topics and requirements

• Definitions and classification of "watertight" vs "quick‑draining" recesses/cockpits.
• Requirements for companionway sill heights and measurement principles.
• Drainage design rules: minimum number of drains, minimum drain diameters and equivalent cross‑sectional areas, and installation guidance.
• Draining time approach: maximum allowable draining time, with three assessment routes — simplified method, enhanced (calculation) method, or test method.
• Hydraulic/head‑loss considerations for non‑circular drains and flow restrictions (annexes provide calculation details).
• Normative watertightness tests and informative worked examples to support calculations and verification.
• Documentation and owner‑manual information requirements related to safe operation and maintenance of drains and closures.

Typical use and users

Used by small craft designers and naval architects, boatbuilders and outfitting suppliers, classification societies and regulators, marine surveyors, test laboratories and safety compliance teams to design and verify cockpit/recess drainage and watertightness. The standard helps ensure cockpits and recesses meet performance criteria for safety and seaworthiness on craft up to 24 m.

Related standards

Commonly used alongside: the ISO 12217 series (stability and buoyancy of small craft), ISO 12216 (windows, portlights, hatches — strength and watertightness), ISO 8666 (principal data for small craft) and ISO 9093 (seacocks and through‑hull fittings). National/adopted versions (e.g., EN/UNE/STN adoptions and the 2024 amendment) may also apply in specific markets.

Keywords

small craft, cockpit, watertight recess, quick‑draining, drain diameter, draining time, companionway sill, ISO 11812, ISO/TC 188, gravity drainage

FAQ

Q: What is this standard?

A: ISO 11812:2020 is an International Standard that sets performance, design and test/assessment requirements for watertight and quick‑draining recesses and cockpits on small craft (up to 24 m).

Q: What does it cover?

A: It covers watertightness criteria, maximum draining time, companionway sill heights, drain sizing and installation, calculation and test methods for verifying drainage by gravity, plus related documentation. It excludes pumped drainage, unattended‑recess scenarios and overall craft stability (handled by other standards).

Q: Who typically uses it?

A: Naval architects, small craft designers and manufacturers, classification societies, marine surveyors, test laboratories and regulatory authorities use ISO 11812 to design and verify cockpit and recess drainage and watertightness.

Q: Is it current or superseded?

A: The 2020 edition (Edition 2) is current and has been amended by Amendment 1 published in 2024 (ISO 11812:2020/Amd 1:2024). The standard remains in force; users should apply the 2024 amendment where applicable.

Q: Is it part of a series?

A: It is part of the small craft family of ISO standards and is commonly referenced alongside the ISO 12217 stability series, ISO 12216 (openings and hatches) and ISO 8666 (principal data).

Q: What are the key keywords?

A: Small craft, watertight, quick‑draining, cockpit, drain sizing, draining time, sill height, gravity drainage, ISO 11812.