Australian navy dives on sunken WWII Japanese midget sub

Australian navy divers collected a jar of sand Monday from next to a sunken Japanese World War II midget submarine now on the ocean floor off Sydney's coast.

The sand will be presented to the families of two Japanese submariners -- Sub-Lt. Katsuhisa Ban and Petty Officer Mamoru Ashibe -- who are believed to have died inside the vessel.

A spokeswoman for the Department of Environment and Water Resources told Kyodo News the sand was collected at the request of Ashibe's relatives and would be given to the families when they visit Australia later this year.

During Monday's dive, the navy also recorded images and did sonar imaging of the submarine, which archaeologists hope will help them piece together what happened to it in its final hours.

The midget sub, which was one of three that took part in Japan's historic raid on Sydney Harbor, was discovered by recreational divers in November last year, following hundreds of false ''discoveries,'' and ending almost 65 years of speculation.

On the night of May 31, 1942 the M24 entered Sydney Harbor and fired torpedoes that missed the U.S. cruiser USS Chicago but exploded beneath the barracks ship HMAS Kuttabul, killing 19 Australian and two British sailors.

Of the other two submarines, one became entangled in a defensive boom net and its two-man crew blew it up, while the other was sunk by a depth-charge attack before it fired any torpedoes.

The shells of those two submarines were both found in the days immediately following the raid.

The discovery of the M24 has thrown up further questions about what happened in the hours of the attack.

The submarine's location to the left of Bungan Heads has puzzled historians because it was supposed to return to a mother-submarine that was waiting to the right.

The M24 has not been opened to search for Ban or Ashibe's remains because of the vessel's fragility. Japanese and Australian authorities have ruled out resurfacing the vessel for the same reason.

Environment Minister Malcolm Turnbull said in a statement the images taken during the dive could shed some light on the mystery still surrounding the M24.

''The inspection will allow archaeologists to analyze the physical and chemical condition of the hull and associated relics, assess any possible battle damage, determine the status of undetonated scuttle charges and provide further clues as to whether the remains of the submariners are aboard,'' Turnbull said in the statement.

Turnbull said the Australian and Japanese governments were considering long-term management options for the submarine.

The Australian government has placed an interim Heritage Order to protect the M24. It carries an A$1.1 million (US$900,000) fine or up to six months jail for anyone who breaches a protected zone around the wreck.