The "flotel" is moored in the River Hudson while negotiations continue with the Prison Service, which plans to ease overcrowding by using the vessel to hold around 500 prisoners. It is expected to be moored in Portland harbour in Dorset.
Bedrooms would become cells, each with their own lavatory and washing facilities. Existing communal facilities would be converted for prison use.
The recreation area would be on the top deck, surrounded by a 20ft-high fence. Any prisoner scaling it would face a 70ft sheer drop.
The ship would be connected to mains water, electricity and drainage. Because it could be moved when no longer required, it would not need planning permission, only the willingness of the harbour authorities and the borough council for it to operate.
The plan to move 500 prisoners from jails in and around Manchester and Liverpool to the prison ship has outraged penal reformers. The partners and families of inmates face round trips of nearly 600 miles to make fortnightly visits, costing up to pounds 100,000 a month in public money for their rail fares. Paul Cavadino, chairman of the Penal Affairs Consortium, said the long journeys would undermine prisoners' relationships with their families. "When families arrive they will be in a fraught state and it will greatly reduce the quality of the visit," he said. "Prisoners released without family support are six times more likely to re-offend soon after their release."
Prison staff said that moving prisoners a long distance was a threat to security and was an important factor in the riots at Strangeways and other jails in 1990. Bev Lord, deputy chairman of the Prison Officers' Association, said: "Couldn't they find a port in the North-west to moor this ship?"
Ministers are said to have approved the plan after prison officials inspected the ship, the Resolution, on Christmas Eve.
A Prison Service spokesman said there was great pressure on jails in the North-west but no final decisions had been taken on which prisoners would be placed aboard the ship.
"We are still seeking to acquire the vessel," he said. "As to exactly where such inmates might be from, it is too early to say at this stage."
The plan is likely to encounter local opposition in Dorset on both aesthetic and environmental grounds.
Bob Beare, deputy mayor of Weymouth and Portland borough council, said: "I have never seen such a monstrosity in all my life. It is not going to do much for our tourist trade." The planning committee had not been given a chance to discuss the plan, he added.
Conservationists are concerned that the ship, with all its potential sewage problems, is due to be moored in a harbour which is a special area for conservation.
English Nature describes the harbour as being one of Britain's most important sites of marine wildlife. Because it is an enclosed harbour on the warm south coast, with particularly fine sediments, it is home to a range of anenomes and rare underwater plants normally found only in the Mediterranean.Reuse content