The 500 pound World War Two device was picked up during dredging work.
Family's Plea To Wanted Man
The family of a 22-year-old wanted for questioning over an attack on a man who was stabbed more than six times in the chest, face and hands on New Year's Eve have urged him to come forward.
The plea comes as detectives release a picture of Arron Peter Marshall who they want to trace.
The attack on the man, 36, took place on the Skilling housing estate near to the Londis shop on Alexandra Road, in Bridport at 2.30pm.
Dorset Police said they are searching for Marshall, who is from Bridport, on suspicion of a serious assault.
In a statement released by police his grandmother, who is not named, said:
''I'm asking Arron to please come forward as the family want to know you are safe and well.
''I want him to know that his family is here for him and will support him.
''Please contact police or your family to let us know that you are safe.
''Your grandparents are anxious to know you are alright and will continue to be there for you.''
Officers were called to the scene by the ambulance service. One of the first to attend the scene was clinical support officer Adam Collinge of South Western Ambulance Service.
Mr Collinge told the papers:
''When we arrived we found a man in his mid 30s had sustained more than half a dozen stab wounds to his torso, face and hands after being stabbed with a knife.
''He needed stabilising at the scene and was then taken by air ambulance to hospital.
''He has suffered potential life-threatening injuries.''
The victim was taken to the Royal Exeter and Devon Hospital where his condition is now described as stable, police said.
Marshall is described as white, of medium build and 5ft 11ins tall. He has a tattoo of writing on his neck and of a koi carp, a snake, and writing on his right arm. He has blue eyes and short light brown hair and walks with a pronounced limp.
Officers are advising members of the public that they should not approach Marshall and should call the police on 999 if they have seen him or know of his whereabouts.
Detective Inspector Stewart Dipple, who is leading the investigation, said:
''It is vitally important that anyone who knows of Arron Marshall's whereabouts contacts Dorset Police urgently.
''If members of the public notice anyone matching his description then I would urge them to call us straight away.
''Do not approach this man - officers will be able to respond immediately.
''Anyone who witnessed the incident on Saturday or has any information that could assist the investigation should call Dorset Police immediately.''
Witnesses and anyone with information should call Dorset Police on 101 quoting incident 31:249 or Crimestoppers, in confidence, on 0800 555 111.
640 men were killed when the South African troop carrier was hit by a cargo ship in 1917.
The 79-year-old man suffered a serious head injury in the Cranmer Road car park in Winton.
Two Girls Indecently Assaulted Last Sunday
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