Hatch Must Be Kept Closed at Sea Sign

Hatch Must Be Kept Closed at Sea Sign – MS0040

The Hatch Must Be Kept Closed at Sea Sign marks a hatch that must remain closed and secured whenever the vessel is underway, protecting the compartment below from downflooding through wave action, spray, or heavy weather. This mandatory sign instructs crew that the hatch is not to be left open at sea, whether it covers a storage space, a machinery access, or a hold, and that it should only be opened briefly and re-secured immediately afterward.

Manufactured from durable photoluminescent material, MS0040 continues to glow after the ship’s main lighting fails, keeping the instruction legible during a blackout, heavy weather, or a night-time watch. Its blue circular mandatory-action field with bold white text is designed for instant recognition at deck hatches and weathertight openings, supporting the IMO’s emphasis on clear, standardised shipboard signage across multinational crews.

Why the Hatch Must Be Kept Closed at Sea Instruction Matters

An open hatch at sea is a well-documented cause of downflooding casualties, particularly in heavy weather when green water can enter a compartment in seconds and compromise the vessel’s stability. A clear, standardised keep-closed instruction reinforces correct watchkeeping and deck practice, reducing the chance that a hatch is left open for convenience during cargo work, ventilation, or routine access, and ensuring it is properly dogged down before the vessel gets underway.

Compliance and Certification

MS0040 is produced to support compliance with the vessel’s Safety Management System under the ISM Code, and weathertight and watertight closing appliance discipline is addressed within SOLAS Chapter II-1 provisions for hull integrity and subdivision. For the full regulatory text, see the IMO’s SOLAS convention overview. Maintaining clear, legible signage at every hatch supports a positive outcome at Port State Control and flag-state inspections.

Installation Recommendations

Install MS0040 directly on or immediately adjacent to the hatch coaming, positioned so anyone opening the hatch sees it clearly before and after use. Mount on a flat, stable surface using marine-grade adhesive or corrosion-resistant fasteners suited to continuous weather exposure. Confirm the sign remains legible under salt spray and UV exposure, and reinforce the instruction through deck watch handover procedures and pre-departure checks.

• Photoluminescent pictogram charges under ambient light and glows during power loss
• Bold mandatory-action blue circle format for instant multilingual recognition
• Rigid, UV-stable substrate engineered for continuous marine and weather exposure
• Compact format suited to deck hatches, coamings, and weathertight openings
• Supports ISM Code safety-management and SOLAS hull-integrity documentation

Equip every hatch aboard your vessel that must stay closed at sea with the MS0040 Hatch Must Be Kept Closed at Sea Sign, and keep watertight and weathertight integrity compliant and reliable when it matters most.

Complete your vessel’s safety signage programme by pairing this sign with our Hazard Signs and Fire Fighting Signs ranges, ensuring full coverage across every shipboard risk area.