The 500 pound World War Two device was picked up during dredging work.
Tabak's Ex Sends Sympathy To Jo's Family
The former girlfriend of murderer Vincent Tabak has extended her ''deepest sorrow'' to Joanna Yeates's family.
Her father added a ''guardian angel'' saved his daughter from the 33-year-old Dutch engineer who hid his depraved sex secrets.
Tanja Morson, 34, initially stood by her boyfriend, finding it impossible to believe he was a killer. But Tabak had deceived and manipulated her.
She turned her back on him after he confessed to a voluntary prison chaplain in February that he had killed the petite 25-year-old landscape architect.
In her only statement, Miss Morson told the Sunday Mirror:
''I would like to extend my deepest sorrow and sympathy to the Yeates family for their loss.
''I am thankful to the judge, the jury, the barristers and solicitors for all their ongoing attention and professionalism.''
On Friday, Tabak was jailed for life with a minimum term of 20 years at Bristol Crown Court after a jury found him guilty of murdering Miss Yeates.
Miss Morson's father, Geoffrey, who lives in Cambridgeshire, told the paper his daughter was still absorbing the verdict.
The Canadian 68-year-old lawyer added:
''He fooled us. He fooled everybody. There was a guardian angel for us, but not unfortunately for Joanna.''
During sentencing Mr Justice Field described Tabak as ''thoroughly deceitful, dishonest and manipulative''.
Mr Morson believes his daughter had a lucky escape from the man he had once thought would become their son-in-law.
Tabak and Miss Morson began seeing each other in November 2008 after she contacted him through the online dating site Guardian Soulmates.
Their relationship developed and by the following June they had set up home together in Canynge Road in Clifton, Bristol.
Miss Morson had dreamt of marrying Tabak, describing him as ''the one'', but those hopes were dashed by the confession from the man she loved that he had strangled Miss Yeates.
Their lives were to be irreparably damaged when Miss Yeates and her boyfriend Greg Reardon moved into the neighbouring ground floor flat on October 25 last year.
The realisation that her boyfriend was addicted to internet pornography and had paid for sex with a prostitute while the couple were together would have been another devastating blow.
Speaking after the verdict Miss Yeates father, David, said no one could have predicted what lay behind Tabak's facade.
''Nobody knows what was in his head when he killed Jo,'' Mr Yeates, 63, said from his home in Ampfield near Romsey.
The IT worker said he believed Tabak had killed his daughter because he feared losing Miss Morson if she found out he had made a pass at Miss Yeates.
Mr Yeates added he felt Tabak was capable of killing his own girlfriend or another woman in the same way he coldly murdered his daughter.
''We felt that if it wasn't Jo, it would have been someone in the future.''
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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