Department for Transport News

20 Jan 2022

MAIB report: Galwad-Y-Mor, subsea explosion, near Cromer, Norfolk

MAIB report: Galwad-Y-Mor, subsea explosion, near Cromer, Norfolk: GalwadYMor Fig02 VesselLowInTheWater crAndrewOliver

Report on the investigation of subsea explosion, resulting in crew injuries and damage to the crab potting vessel Galwad-Y-Mor (BRD 116), 22 nautical miles north of Cromer, Norfolk, on the 15 December 2020


At 11.22 on 15 December 2020, the 15m crab potting vessel Galwad-Y-Mor was hauling pots in the North Sea approximately 22 miles north-east of Cromer. The crabbing gear disturbed a 250kg unexploded WWII bomb, which detonated on the seabed below the vessel.

The ensuing explosion caused a shock wave that threw Galwad-Y-Mor about, resulting in significant injuries to five of the seven crew and major damage to the vessel’s hull and machinery. Despite their injuries, Galwad-Y-Mor’s crew were able to send a distress message, launch the liferaft, and board rescue boats that had been dispatched by a nearby offshore support vessel. The injured crew were transferred to hospital by helicopter and RNLI lifeboat. They were treated for head, back and knee injuries. Galwad Y Mor was successfully salvaged and has been rebuilt.

The key safety issues identified were:

  • Unexploded ordnance (UXO) can be highly volatile even after many years of being submersed. In the event of encountering a UXO, seafarers are advised to follow the recommendations in MGN 323 (M+F) Explosives Picked Up At Sea.
  • Galwad-Y-Mor’s crew could not have anticipated the fouling of a bomb in the potting string and the resulting explosion; their training, experience and emergency preparedness improved their chances of survival.

Contact Information

Anna Withrington
Head of External Communications Air, Marine and Rail Accident Investigation Branches
Accident Investigation Branches (AIBs)
01932 440015

Notes to editors

  • Image must be credited to Andrew Oliver
  • A copy of the Report is available for media to download below. The Report will be published on the MAIB website at 10am.