|MONTEBELLO was purpose built in 1921 to transport petroleum products in bulk as well as case oil cargo in dry storage holds below the shelter deck for the Union Oil Company of California. The tanker was constructed at the Southwestern Shipbuilding Company, located in East San Pedro, California. The shipyard constructed only 7 tankers with the MONTEBELLO being the largest of the tankers built at the yard with a 12,000 deadweight tonnage and liquid cargo capacity of 82,050 barrels. The Union Oil Company of California had 12 steel and iron tankers in their fleet between 1913 and 1931, MONTEBELLO had the second largest cargo carrying capacity, with the tanker Santa Maria rated slightly larger at 85,000-barrel carrying capacity. MONTEBELLO made deliveries to South America, Central America including the Panama Canal Zone, U.S.S.R., China, Canada, as well as U.S. Pacific ports. MONTEBELLO was one of the first tankers in the Union Oil Company fleet to transport molasses from Hawaii to the U.S. mainland early in its career. Following the attack on Pearl Harbor, the Union Oil Company's fleet of tankers were taken over by the U.S. War Shipping Administration, that reassigned the tankers, together with other government oil carriers, back to Union Oil for operation. Prior to the Pearl Harbor attack, Union Oil tankers had been carrying British oil between the Dutch West Indies and the Atlantic Coast; and three more had delivered petroleum products to European Allies via the Soviet port of Vladivostock and to American bases in the Pacific. The MONTEBELLO, along with other slow moving tankers typically sailed in the Pacific unscored, and their explosive cargoes made them vulnerable. Shortly after the attack on Pearl Harbor, Hawaii, Admiral Mitsumi Shimize, Commander of the Imperial Japanese Sixth Fleet, ordered 9 new ocean-cruising submarines to patrol off the U.S. Pacific mainland coast. On 23 December 1941 at 1:30 A.M., MONTEBELLO with a crew of 38 men passed the breakwater buoy departing Port San Luis, California north for Vancouver, Canada laden with crude oil. At 5:40 A.M. the Japanese submarine I-21 was spotted and the captain ordered the helmsman to take an evasive action by zig-zagging their course and heading for shallower waters in an attempt to evade the submarine. MONTEBELLO was struck in the bow by a single torpedo causing the tanker to sink. The crew of 38 men escaped in four lifeboats and all survived due to the heroic actions by local citizens. Of the 16 freighters and tankers attacked between Cape Flattery, Washington and as far south as San Diego, California between 1941 and 1942, 2 freighters and 4 tankers including the MONTEBELLO were lost. Of the 4 tankers sunk along the continental United States during the Japanese campaign in the eastern Pacific, the MONTEBELLO shipwreck represents the most complete and undisturbed archaeological remains, this is due in-part to the deep waters where it lies. The shipwreck was first located in 1945 off Cambria, California using a drop camera from surface vessel. The first archaeological man-submersible investigations were conducted in 1996 and 2003, verifying the location 1.44 nautical miles south of Monterey Bay National Marine Sanctuary at a depth of 885 feet. The archaeological remains of MONTEBELLO are potentially significant at the national level under National Register of Historic Places Criteria A and D with the period of significance being the year 1921-1941.