[1] In the East African campaign of World War I, the Royal Navy protected cruiser HMS Hyacinth attacked and damaged a German auxiliary ship off Manza Bay on 14 April 1915.

The German Navy had disguised Rubens as the Danish cargo ship Kronborg and sent her to replenish the cruiser SMS Königsberg in the Indian Ocean.

[2] The German crew succeeded in beaching their ship in the bay, salvaged all the arms and ammunition from Rubens' cargo, and abandoned her.

In 1956 an Italian salvage company repaired Rubens' hull, refloated her, towed her to Dar es Salaam with two tugboats and sold her coal to the East African Railways and Harbours Corporation.

[2] In World War II the Royal Navy laid indicator loops off Manza Bay to defend the coast against German and Japanese submarines.