The 500 pound World War Two device was picked up during dredging work.
'Lives Put At Risk' In Dorset
Dorset Fire and Rescue say lives were put at risk after a fire at a property in Swanage.
It broke out in a ground floor flat in Victoria Road as crews were dealing with a heathland fire at Studland on Sunday evening.
Everyone was later accounted for.
Dorset Fire and Rescue tweeted saying "Lives were put at risk due to fire on Heath at Studland. We cannot be in two places at once!!"
Just hours earlier firefighters had also been tackling a fire on Canford Heath.
Both heathland fires are being treated as deliberate.
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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