Grimsby boat crew lucky to be alive after WW2 bomb explodes in North Sea

Crew members on a boat that set sail from Grimsby were “fortunate not to be killed” when their vessel disturbed 250kg unexploded World War II bomb, which detonated on the seabed.

The crew set out on Galwad-Y-Mor, which was hauling in crab pots in the North Sea approximately 22 nautical miles north-east of Cromer in Norfolk on December 15, 2020. The line disturbed the air-dropped bomb, which had remained intact on the seabed since the Second World War.

The ensuing explosion caused a shock wave that threw the boat about, resulting in significant injuries to five of the seven crew. Despite the injuries, Galwad-Y-Mor’s crew were able to send a distress message, launch the life raft and board rescue boats that had been dispatched by a nearby offshore support vessel.

Galwad-Y-Mor structural damage. | Photo: Marine Accident Investigation Branch

The vessel’s hull and machinery sustained major damage and the Marine Accident Investigation Branch released a report into the incident on Thursday, January 20, 2022 – read the full report here.

The report states most of the injuries experienced by the crew were of a blunt force trauma nature. These were said to be “consistent with tertiary injuries most likely caused by the acceleration forces the crew experienced when Galwad-Y-Mor was thrown about”.

The metal fragment was magnetic and measured 94mm in length, 129mm in width and had a 7.41mm average thickness. | Photo: 1710 Naval Air Squadron

The head injuries to deckhands one and three, who were not wearing safety helmets, suggests they struck the deckhead at the time of the accident, the report adds.

The skipper was seated when the bomb exploded and struck his head on the wheelhouse deckhead, which caused injuries to his eye socket and face. His back and knee injuries were probably incurred when he landed back down on the deck.

Physical injuries were significant to five of the seven crew and the report says “they were fortunate not to be killed”. The injured crew were transferred to hospital by helicopter and lifeboat. They were treated for head, back and knee injuries.

The report states the crew “could not have anticipated the fouling of a bomb in the potting string and the resulting explosion” and that “their training, experience and emergency preparedness improved their chances of survival”.

Galwad-Y-Mor machinery damage. | Photo: Marine Accident Investigation Branch

Galwad-Y-Mor interior damage. | Photo: Marine Accident Investigation Branch

There was extensive deformation to the hull plating of the vessel, and the engine room was flooded. There was also severe shock damage in all internal compartments.

In terms of vessel damage, the report says that “the potting string quickly tightening at the hauler suggested that the bomb was directly below the vessel on the seabed prior to the explosion”. The boat’s machinery mountings and internal fit out were damaged because they were “not designed to withstand the forces created by the action of the vessel being thrown about”.

Galwad-Y-Mor settled low in the water. | Photo: Andrew Oliver

The report adds: Galwad-Y-Mor was “close to the explosion and well below the MOD’s recommended 530m safe stand-off distance for non-military vessels to be unaffected by a seabed explosion of this size.

“Nevertheless, Galwad-Y-Mor’s thick shell plating presented good resistance to the shock wave generated by the explosion, and the heavy section box keel was able to resist bending forces set up by the pulse bubble underneath the vessel.”

Based on the accident’s circumstances, the Marine Accident Investigation Branch said no action has been taken by external stakeholders and no recommendations made. Galwad-Y-Mor was successfully salvaged and has since been rebuilt.