Why did the ships crash in the North Sea? What tracking data and inspection reports reveal

Analysis by Sky News reveals that human error is the most likely cause of the collision between the container ship Solong and US oil tanker Stena Immaculate.

The Portuguese-flagged Solong had sailed the same route 19 times in the past five months before the collision, which occurred off the east coast of Yorkshire at 9.47am on Monday 10 March.

Authorities from the US and Portugal will reportedly lead the investigation, while Humberside Police is also working with the UK's Marine Accident Investigation Branch to establish what happened.

Ship safety expert Mel Irving told Sky News: "At the moment, it looks like 100% human error. We can only assume nobody was watching. Nobody was at the controls. Nobody was aware that there was a ship right ahead."

The arrested captain of the Solong is a Russian national, while the rest of the crew were Russian and Filipino nationals, according to German shipping company Ernst Russ.

What tracking data tells us

The Solong has taken an almost identical path along the Yorkshire coast 19 times over the past five months. On those occasions, it travelled to or from Grangemouth in Scotland to either Hull or Rotterdam in the Netherlands.

So what went wrong this time? Sky News' Data & Forensics unit has analysed the ship's tracking data.

Speed variations of the vessel along the same route over the past year are in the same range as Monday's collision.

The vessel was travelling at around 16 knots when it hit the oil tanker, according to ship tracking data from MarineTraffic. Over the past five months, it travelled at speeds between 11 and 17 knots at around the same point.

Despite passing along the coast of Yorkshire multiple times recently, the Solong did not travel along the route in 2023 or 2022.

Over the past five months, the cargo ship mostly travelled in the area along a relatively straight line, suggesting its autopilot was in use.

Mr Irving said: "Even if a crew has sailed a route repeatedly, every journey is different – traffic, weather, visibility, and anchorage positions change. That's why proper watchkeeping is essential".

Visibility in the area at the time of the crash had been poor with areas of fog, according to the Met Office. The still image below is taken from a nearby ship at the time of the collision.

How many ships are usually in the area?

On the day of the collision, the Stena Immaculate had been anchored off the Yorkshire coast alongside eight other large tankers and container ships. It did not move for 15 hours, having anchored at 6.30pm the night before.

A week before the crash, on 3 March, the Solong took an almost identical path as on the day of the crash. Its path was 500m different and it travelled at a similar speed. It would have missed the tanker that day.

The past three times the Solong travelled through the area, while heading in the same direction, there were fewer anchored ships. On 3 March, there were two such vessels. On 24 February, there were four ships, while on 17 February there were three.

Mr Irving, who works at South Shields Marine School, said: "An anchored ship is not just sitting there passively – it has a responsibility to maintain a proper watch. Someone should have been on duty, monitoring nearby traffic and potential risks."

Why was the Solong not detained?

The Solong container ship which crashed in the North Sea had repeatedly failed safety inspections in recent years, with ongoing issues in steering, navigation, and emergency systems. However, it had never been detained by authorities.

Irish officials previously found that Solong's "emergency steering position communications/compass reading" was "not readable" according to port state control (PSC) inspection documents from July last year.

It was among 10 deficiencies highlighted during an inspection of the vessel in Dublin. Other issues included alarms being "inadequate", survival craft "not properly maintained", and fire doors "not as required".

The inspection was not an isolated case. Steering and navigation failures had been flagged multiple times, including a steering gear malfunction in 2022, a missing spare magnetic compass in 2020, and a steering gear deficiency in 2016.

Mr Irving said "Ten deficiencies on a ship is not unusual, especially with older vessels. It's like advisories on an MOT test – issues that need to be fixed before the next inspection, but not necessarily enough to stop the ship from sailing."

Ships are typically detained when deficiencies pose an immediate threat to safety, the environment, or crew welfare.

The official investigation will focus on why there was no evasive action to prevent the collision. Mr Irving said that the Voyage Data Recorder (VDR) would be key in determining whether the officer on watch was present, paying attention or distracted.

The biggest question is why no action was taken in the moments before the crash.

The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open-source information. Through multimedia storytelling, we aim to better explain the world while also showing how our journalism is done.

(c) Sky News 2025: Why did the ships crash in the North Sea? What tracking data and inspection reports reveal