Offshore and remote environments

Hazards

• Turning blades and tower structures limit helicopter flight paths and hover positions.
• Turbines cause radar clutter, false returns and shadow zones behind towers.
• Scour protection, cables and shallow banks around turbine foundations.
• Crew transfer vessels, service ships and walk-to-work vessels on site.
• Survivors often hold onto or climb turbine foundations and boat landings.

Typical responders

• Site crew transfer vessels (CTVs) and daughter craft - usually the fastest first responders
• Coastguard SAR helicopter (winch-capable, needs turbines stopped and blades parked)
• RNLI / volunteer lifeboats
• Site drones with thermal cameras for corridor sweeps

Survival

North Sea water is often 5-15 °C: expected survival of a few hours without an immersion suit.

Recommended pattern: Array-Aligned Corridor Search (AACS) - Legs follow the turbine rows so boats and aircraft move through clear corridors.

Hazards

• 500 m statutory safety zone around the installation.
• Gas release, flare radiation and helideck turbulence near the structure.
• Anchor lines, risers and subsea equipment for floating units.
• Supply vessels and shuttle tankers manoeuvring close in.

Typical responders

• Emergency response and rescue vessel (ERRV) with fast rescue craft
• Installation lifeboats and life rafts
• Offshore SAR helicopter
• Nearby supply and standby vessels

Survival

Platform crews wear survival suits for helicopter transfers, which greatly extends survival.

Recommended pattern: Safety-Zone Ring and Downdrift Box - Rings start outside the 500 m safety zone while a second unit sweeps the drift box.

Hazards

• Hours or days before a rescue unit arrives; the search area keeps growing.
• Helicopters out of range; long-range aircraft can drop rafts but not recover people.
• Merchant ships diverted under SOLAS may be the only surface units.
• Heavy seas and swell make small targets hard to see.

Typical responders

• Long-range maritime patrol aircraft (search, drop stores, relay)
• Merchant vessels diverted by the rescue coordination centre
• Naval and coastguard cutters
• Satellite beacons (EPIRB / PLB) through Cospas-Sarsat

Survival

Survival depends on water temperature, flotation and shelter - rafts can last days.

Recommended pattern: Drift-Aligned Parallel Box - A long box aligned with the drift direction, searched in parallel legs.

Hazards

• Water near -1.8 °C: incapacitation within minutes, survival often under an hour.
• Sea ice, growlers and ice edges obstruct boats and hide survivors.
• Long darkness, fog, icing on aircraft and vessels.
• Very sparse assets and poor communications coverage.

Typical responders

• Ice-class vessels and research icebreakers
• Long-range helicopters from ships or stations
• Fixed-wing aircraft with thermal sensors
• Satellite beacons and satellite phones

Survival

Cold shock and swim failure mean the first 10-30 minutes are decisive.

Recommended pattern: Ice-Edge Contour, Time-Boxed - Legs follow the ice edge where survivors collect, with a hard cold-water time limit.

Hazards

• Mooring lines, instrument buoys and towed or suspended equipment.
• Small crews with limited rescue capability on the facility itself.
• Moored arrays can foul propellers of rescue boats.

Typical responders

• Facility rescue boat or research vessel
• Nearby fishing or supply vessels
• Coastguard helicopter where in range

Survival

Crews often work over the side - personal locator beacons speed up detection.

Recommended pattern: Mooring-Aware Sector + Expanding Square - Fast sector search at the datum, then an expanding square that avoids mooring lines.