Working Overside & Aloft: Safety Guide

Working overside — over the ship's side into the water — and working aloft in masts, funnels, and cranes are among the highest-risk activities in the maritime environment. Falls from height and man-overboard incidents during deck maintenance are recurring causes of serious injury and fatality at sea. Yet both activities are routine parts of vessel maintenance across all sectors.

This guide covers the safety requirements, permit-to-work procedures, PPE standards, weather and sea-state limits, and rescue planning that must be in place before any overside or aloft work begins.

Why These Activities Are High Risk

The combination of height, movement (vessel roll and pitch), environmental conditions (wind, sun, temperature), and the physical isolation of the work position creates a hazard profile that goes well beyond typical shore-based working-at-height situations. Add salt-corroded equipment, awkward access angles, and the ever-present possibility of falling into the sea, and the risk profile becomes clear.

Common causes of incidents during overside and aloft work include:

• Failure of staging, bosun's chairs, or securing arrangements
• Unexpected vessel movement causing loss of footing or balance
• Improper PPE — particularly fall arrest equipment not rated for the work position
• Working in deteriorating weather without monitoring
• No rescue plan in place before work begins
• Working alone without communication

The Permit to Work System

All work overside or aloft must be covered by a formal Permit to Work (PTW). This is not optional — it is required under ISM Code procedures and the SMS of any properly managed vessel. The PTW serves three purposes:

1. Forces a pre-work hazard assessment specific to the actual conditions on the day
2. Defines who is responsible for monitoring the work and the person working
3. Confirms that rescue arrangements are in place before work begins

The PTW must be signed off by the responsible officer (typically the chief officer for deck work) and must not be issued until all safety measures are confirmed in place. Work must stop if conditions change and the permit may need to be reissued if there is any significant break in the work.

Risk Assessment: What to Cover

A proper risk assessment for overside or aloft work addresses:

Environmental conditions

• Wind speed and direction — most operators set maximum limits around Beaufort 3–4 for aloft work and similar for overside
• Sea state and vessel motion — even apparently calm conditions can result in unexpected rolls
• Visibility — low visibility creates additional hazards if the vessel is moving
• Temperature — extreme heat causes fatigue and impairs judgement; cold reduces manual dexterity

Work position and access

• How will the worker be secured at the work position?
• What is the rescue route if the worker is incapacitated?
• Can the work be done from a safer alternative position?

Vessel status

• Is the vessel at anchor, alongside, or underway? (Work is generally prohibited when underway unless specifically risk-assessed)
• Are other deck operations running that could create additional hazards (mooring, cargo, crane operations)?
• Is the vessel taking ballast, which could affect stability and trim mid-job?

PPE Requirements

For working aloft

The minimum PPE for working aloft includes:

• Full-body harness — not a chest harness or safety belt. A full-body harness distributes arrest forces across the torso and thighs, reducing injury risk during a fall. It must be inspected before each use and have a current examination certificate.
• Shock-absorbing lanyard — with a length appropriate to the work position. The lanyard must be attached to a certified anchor point, not improvised rigging.
• Safety helmet — with chin strap secured
• Non-slip footwear
• Gloves — appropriate for the work being done
• Communication device — walkie-talkie or equivalent to maintain contact with the standby person

For working overside

• Full-body harness with lifeline attached to a secure point on deck above the work position
• Approved personal life jacket (PLJ) — worn, not just available
• Immersion suit or thermal protection depending on water temperature
• Waterproof communication device or whistle
• Bosun's chair or stage must be rated and inspected — never use improvised staging without a structural assessment