Mr Wiswell, who turns 88 in July, was in Canberra yesterday for the formal declaration of the USS Lexington, the USS Sims and the USS Neosho - all lost during the Battle of the Coral Sea - as ''protected historic shipwrecks''.

He was one of thousands of young sailors and airmen hailed as heroes by US ambassador Jeffrey Bleich for their service.

''We looked to these young men - and we asked them to put their lives on the line - to give the free world something to believe in,'' Mr Bleich said. ''At that dark hour we desperately needed to stop Japan and the world needed hope.''

Three other veterans of the battle, Australians Derek Holyoake and Gordon Johnson, and Harry Frey - who also served aboard USS Lexington - were at the ceremony at the Australian War Memorial. The Lexington wreck is the last resting place for at least 111 of Mr Wiswell's shipmates. Their sacrifice stopped a Japanese invasion force bound for Port Moresby and put paid to any plans the Japanese may have had to invade Australia. Another 419 men died aboard USS Sims, a destroyer, and USS Neosho, a replenishment vessel.

Mr Wiswell could not believe the behemoth he had only joined seven months before could sink.

At 270 metres from end to end, she was longer than Titanic and had anti-torpedo defences and massive armour plating.

''I stayed on board for an hour after the order to abandon ship,'' he said. ''I thought we'd be able to salvage her.''

The ship, originally laid down as a battlecruiser after WWI and with a top speed of 33 knots, was one of the largest vessels to see service in the Pacific War. A Seaman 2nd Class at the time, Mr Wiswell had been on kitchen duty before the battle.

On the morning of May 8, 1942, the day the ship known affectionately to her crew as ''Lady Lex'' met her doom, he and the other mess cooks were told to stay in the galley and await assignment to rescue, firefighting, combat or other duties as required.

''I ended up going to help the doctor with the wounded,'' he said.

It was a hard task and he saw horrible things. ''I was washing faces and trying to console the wounded. Some were beyond hope.''

Mr Wiswell, who had made his way to the flight deck with the rest of the remaining crew after fires spread through much of the ship, knew it was time to leave when the stricken vessel began to settle.

''She had been listing to port a few degrees,'' he said. ''All of a sudden she dropped a few feet and I said to myself, 'Time to leave now'.''

Yesterday's ''historic shipwreck'' declaration recognises the significance of the remains of USS Lexington, USS Sims and USS Neosho as maritime military graves.

''It ensures that any action that could result in damage, interference, removal or destruction of these wrecks or their associated relics is illegal,'' a spokesman for Heritage Minister Tony Burke said.