which were machine-gunned by I-21 with no casualties. Montebello sank in of water about south of Piedras Blancas Light at . In November 1996, a team of marine researchers surveyed and filmed the wreck in a two-person submarine. Montebello, apparently still loaded with of crude oil, was discovered to be resting on the sea floor in of water adjacent to the Monterey Bay National Marine Sanctuary. The wreck was reexamined in 2010 for the level of deterioration and to determine if the oil was still in the hold and if so, did it pose an environmental threat. The researchers reported in October 2011 that the cargo had dissipated into the vast ocean shortly after sinking. Shelling of Newcastle, Australia On 8 June 1942, I-21 briefly shelled Newcastle, New South Wales. Among the areas hit within the city were dockyards and steel works. There were no casualties in the attack and damage was minimal. Possible sinking of USS Porter On 26 October 1942, in the Battle of the Santa Cruz Islands, I-21 is credited in most sources with sinking of the destroyer . However, author Richard B. Frank states that Japanese records do not support this, and that, more likely, an errant torpedo from a ditching U.S. Grumman TBF Avenger hit Porter and caused the fatal damage. Sinking of SS Kalingo On 17 January 1943, I-21 torpedoed and sank the Union Steam Ship Company's SS Kalingo about east of Sydney. Two firemen were killed when the torpedo hit, and 32 of her crew reached safety in a boat. Sinking of SS Iron Knight The BHP Shipping iron ore carrier was part of a convoy of ten ships travelling up the east coast of New South Wales on 8 February 1943. At approximately 2:30 am, north of Twofold Bay, I-21 fired a torpedo at the naval ships flanking Iron Knight at the head of the flotilla under cover of darkness. The torpedo passed under the bow of the and struck Iron Knight, sinking her with the loss of 36 crewmen, including her commander, in less than two minutes. Most of the ship's crew were below decks and were unable to escape as the ship went down. Only 14 survived, clambering aboard a single lifeboat to be picked up by the . , the other corvette guarding the convoy, pursued the I-21 for several days. On 4 June 2006, the wreck of Iron