Clean as a whistle and ready to sail back to the museum

After receiving a meticulous scrape, repaint and polish over two weeks, the submarine HMAS Onslow is ready to be the Australian National Maritime Museum drawcard again.

The vessel underwent a $100,000 refit at Garden Island dockyard and was towed back home by 11am Thursday.

The cold war veteran was given a good coat of anti-fouling paint, four years' worth of marine growth on its hull was removed with high pressure blasting and repairs were made to its rear torpedo tubes. The refit occurs every four years.

“To a ship, the waters of Darling Harbour are stagnant. There's not much movement and she's static obviously,” said the museum's senior naval curator, Lindsey Shaw. “As one of our fleet members said, the marine growth is a source of food for our fish population. But it breaks down the paint and causes corrosion.”

HMAS Onslow was launched in 1968 and was one of six Oberon class submarines. The 89.9 metre vessel, which had an original crew of about 60, was decommissioned from the Royal Australian Navy in 1999.

Mr Shaw said some mariners and naval tragics were still nostalgic about how advanced Oberons were. They were appreciated for combining high speed and underwater endurance with attack capabilities.

“They were diesel-electric because the navy doesn't have nuclear submarines. They are very quiet vessels and they're most secretive work was tracking soviet submarines,” Ms Shaw said.

During its glory days, the vessel travelled across the Pacific and Indian oceans, reaching as far as the Arabian Gulf and notching up more than 660,000km.

The submarine will be back on show this weekend.