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Solong / Stena Immaculate: The Lone Watch in the Fog

🕑 5 min read words Safety • Incident • Colregs

Vessels: Solong (Container Ship, built 2005, 7,852 GT) & Stena Immaculate (Oil/Chemical Tanker, built 2017, 29,854 GT)
Date: 10 March 2025
Location: 14nm north-east of Spurn Head, Humber Estuary, England
Outcome: Fatality — Able Seaman, Solong; major fire and structural damage to both vessels
Human Factors: Lone Watchkeeping · Lookout in Restricted Visibility · Familiar-Route Complacency
Source: MAIB Interim Report, April 2025 (investigation ongoing)

2 decision points · 4 outcome paths · 6 min read

What Happened

On 9 March 2025, the US-flagged tanker Stena Immaculate anchored 5 miles north of the Humber light float, on the instruction of Vessel Traffic Services, with a cargo of aviation fuel and eight other vessels anchored in the same area. That evening, the Portugal-flagged containership Solong departed Grangemouth on a passage to Rotterdam — a route it had sailed before.

The master remained on watch until shortly before 2300, then handed over to the second officer. At 0700 the following morning, the master returned to the bridge and took over as the lone watchkeeper. Visibility in the area north of the Humber light float was patchy, varying between 0.25 and 2.0 nautical miles. Neither Solong nor the anchored Stena Immaculate had a dedicated lookout posted.

At 0947, Solong — on a heading of 150° at roughly 16 knots — collided with the anchored Stena Immaculate's port side.

Fire on the Water

The collision breached Stena Immaculate's No.7 port cargo tank, releasing aviation fuel into the sea and onto Solong's bow. The heat of the collision ignited the fuel, and the resulting fire spread to ignite containers on Solong's deck — some carrying dangerous goods. Both crews fought the fire as it escalated, hampered by its severity. Able Seaman Mark Pernia, reported to be in Solong's forecastle area at the time of the collision, could not be found. Both crews ultimately abandoned to lifeboats and were recovered by local boats and HM Coastguard. Mr Pernia has not been found and is believed to have died in the accident.

What the Interim Report Confirms — and What's Still Open

This is an interim report: MAIB's full investigation, covering navigation and watchkeeping practices on both vessels, manning and fatigue management, vessel condition, the use of the area as an anchorage, and the environmental conditions, is still ongoing. What the confirmed facts already establish is the shape of the failure: a lone watchkeeper, on a familiar route, navigating at speed through patchy fog into a known anchorage area, with no dedicated lookout posted on either vessel.

None of that is unusual on its own. Solo bridge watches and no-lookout-in-clear-weather happen daily across the industry without incident. What changed the calculus here was restricted visibility down to a quarter of a mile, in an area both vessels' own information should have flagged as busy — and neither ship adjusted its practice to match.

Recommended Actions

When visibility drops into the sub-1nm range, post a dedicated lookout, in addition to the watchkeeping officer — this is a COLREGS Rule 5 obligation, not a discretionary safety extra.
Treat "a route we've sailed before" as informational context, not a reason to lower vigilance — familiarity with a passage doesn't reduce the risk posed by other traffic that wasn't there last time.
In restricted visibility, reduce to a safe speed that allows proper and effective action to avoid collision, per COLREGS Rule 19 — assess whether 16 knots is defensible given the actual visibility, not the forecast visibility.
When approaching or transiting a known anchorage area, increase situational awareness proactively rather than waiting for a specific contact to appear on radar or AIS.
Review your vessel's lone-watchkeeping policy against actual visibility and traffic density conditions, not a blanket day/night or open-water/coastal rule.

Human Element Analysis

Lone Watchkeeping

A single watchkeeper managing navigation, traffic assessment, and lookout duties simultaneously in patchy fog has no redundancy if their attention is drawn elsewhere, even briefly.

Lookout in Restricted Visibility

COLREGS Rule 5 requires a proper lookout "by sight and hearing as well as by all available means" appropriate to the prevailing circumstances. Visibility of 0.25–2.0nm is exactly the circumstance that requires more than routine watchkeeping.

Familiar-Route Complacency

Solong's passage followed a route "the vessel had used in the past." Familiarity can quietly substitute for active risk assessment — the mental model of "this passage is normally fine" persisting even as the actual conditions on a given day depart from normal.

Industry	Incident	The Parallel
Aviation	Tenerife Airport Disaster, 1977	Two aircraft collided in fog on a runway both crews knew well — familiarity with the environment didn't compensate for severely restricted visibility, the same gap that preceded the Solong/Stena Immaculate collision.
Rail (UK)	Ladbroke Grove Rail Crash, 1999	A signal with a known poor sightline was passed at danger by a driver operating alone in the cab — a single point of human attention, without an independent backup system, proving insufficient under degraded conditions.
Offshore (North Sea)	Piper Alpha, 1988	A known hazard (poor shift-handover communication) was tolerated because it hadn't caused a catastrophic failure yet — the same pattern as a familiar route sailed without incident until the one day conditions were genuinely different.

See How You’d Handle It

Solong's decision simulator puts you on the bridge as the lone watchkeeper, in patchy fog, approaching a known anchorage area. Two decision points, four outcome paths — one of them the real one.

Test Your Knowledge

Think you've got this covered? Put it to the test in Crew Connect's free Knowledge Checker — try a quick COLREGS round and see how you score.