Royal Navy divers were called to deal with a suspected World War II mine netted by a fishing boat off the coast of Hartlepool.
The two-man crew of the Osprey remained on board as Hartlepool's all weather lifeboat stood off close by.
They described the object as a "rusty, spherical and with spikes" and were advised by coastguard officials to move to a point two miles offshore.
It was hoped the mine could be lowered to the sea bed to be safely dealt with.
Coastguard officers put the vessel in contact with Explosives and Ordnance Division (EOD) divers who confirmed that the object was a World War II mine. Humber Coastguard watch manager Drew Mahood said: "Fishermen still occasionally trawl up ordnance and munitions from World War II.
"When this happens, we ensure that they are put in touch with our colleagues at the EOD who can assist them in disposing of their potentially explosive catch."