Defence minister Willie O'Dea turned down an offer by a project management company to buy the supposedly unsalvageable Asgard II for €1 and then sell it back to the state after it was salvaged.

The government has been approached by a number of companies interested in refloating the vessel, which sank 22km off the coast of France while on a training run to La Rochelle on 11 September last year.

All 25 crew and trainees were evacuated to life rafts when the ship began taking in water. The 27-year-old brigantine sank several hours later.

The Department of Defence decided to abandon the Asgard II at the bottom of the sea and to build a replacement ship, which would be less expensive and easier to maintain.

O'Dea has confirmed that he received a "number of queries" from people interested in salvaging the vessel but that a deal had not yet been reached.

In one of the deals, a project management company offered to buy the ship for €1 and then sell it back to the state after it was salvaged.

The Department of Defence said the Asgard II would always remain in state ownership and that it would not be sold in any circumstances.

Two underwater video surveys commissioned following the sinking last year found it would be uneconomical to refloat the ship.

The initial survey, carried out between 26 and 29 September, showed that the vessel was still lying upright in 80m of water and appeared to be largely intact. Apart from some obvious damage to a plank in the hull, the video did not show any major damage. A second survey begun on 28 January could not be completed because of adverse weather conditions. However, a sonar image of the vessel was obtained, which again showed the vessel was in an 'upright position'.

The decision to abandon the Asgard II was made on economic grounds. O'Dea told the Dáil: "Spending in the region of €2m on a salvage effort, the outcome of which is uncertain, is something we cannot afford at this time.

"A real risk exists whereby more than €2m could be expended on a salvage effort that proves unsuccessful or, following which, the vessel is found to be damaged beyond repair."

It was also believed that ships are "never the same" after restoration and that there would be huge ongoing maintenance problems as a result of the sinking.

"The board also took into account the view that parents of potential trainees... may be reluctant to allow their children to sail on a vessel that has sunk," said O'Dea.

A statement from the department said: "Various queries were received enquiring as to the ownership of Asgard II. Of these queries, only one party put forward a proposal to purchase Asgard II for a nominal sum of €1 and then make her available to the minister for the total costs incurred by the team when the vessel was returned to Ireland.

"This did not come within the scope of what the minister was willing to consider. The approach was made by a project management company on behalf of a number of individuals. No details of costs, funding, etc were provided.

"The minister has already stated that he is willing to consider realistic and funded proposals for salvage and that offer still stands. However, Asgard II will always remain the property of the minister and it will not be sold."