Under the name Kettara IV, she was sunk by shell fire off the Vietnamese coast in 1966, with the loss of her entire crew.

[14] In mid December 1934, en-route from Rockhampton to Brisbane, she was following a route too close to shore for a ship of her type, when she struck rocks and sustained some damage.

Fortunately, Canonbar’s captain presciently had attached a line to the rocket, allowing the container holding the mail to be dragged back to the ship, from where the letters were taken to Pinkenba and posted.

Serious stamp collectors of the time saw these rocket launches as bringing only ridicule upon those involved[20][21][22] and the Post Office dissociated itself from any connection to these farcical, somewhat dangerous, and probably illegal experiments.

[23] However, in a manner, their work succeeded, as the commemorative covers from the 1934 rocket launch—and those from a later experiment in 1935, involving Maheno[22]—are still a collectors’ item, over 80 years later, and one of the few tangible reminders today of Canonbar.

During the Second World War, Canonbar was requisitioned by the Australian Government and then used by the United States as a supply ship for the South-West Pacific Campaign.

Canonbar, was only briefly owned by Carroll Shipping Company, for later in 1949 she was sold to Cia Navegacao De Sousa Ltda, of Hong Kong, and was renamed Rosita.

Her last owner was Tiong Lam Hang Shipping Co SA, of Panama, who bought her in 1964 and renamed her Ketarra IV.

[1][2] On 16 March 1966, Kettara IV, was carrying a load of cement and general cargo from Singapore and bound for Da Nang, when she came under shellfire from the North Vietnamese Army, in the vicinity of the Demilitarized Zone (DMZ).