West Conob—a steel-hulled, single-screw freighter completed in 1919 at San Pedro, Calif., by the Los Angles Shipbuilding and Drydock Co.—was inspected by the Navy in the 12th Naval District for possible naval service. However, although the ship was assigned the Navy identification number Id. No. 4033, she was never taken over by the Navy.
Instead, West Conob entered merchant service—first with the United States Shipping Board and then with the United States Maritime Commission after that agency's establishment in the 1930's. Operated by the Matson Navigation Line, which renamed her Golden Eagle in 1934 and Mauna Loa in 1940, the ship was chartered by the War Department on 18 November 1941 to carry supplies to Manila.
Re-routed to Australian waters as the Japanese invasion of the Philippines had made the islands untenable, Mauna Loa subsequently arrived at Brisbane. Then, when ordered to Port Darwin, the ship's master filed a protest with the American consul in Brisbane and got underway, "under protest." The freighter loaded elements of the United States Army 148th Field Artillery Regiment and sailed in convoy on 15 February 1942 for Timor with three other merchantmen and four escorts.
The Japanese soon pin-pointed the convoy's position through the persistent efforts of a four-engined flying boat—a "Mavis"—which spotted the convoy on the day they sailed. Before drawing away, the "Mavis" dropped a stick of bombs, all of which missed. Another "Mavis" returned the next day, continued the snooping, and called for more help. It soon arrived, in the form of 36 twin-engined bombers and nine flying boats from Kendari in the recently secured Celebes.
Houston (CA-30) put up a terrific barrage of antiaircraft fire which, to one eyewitness, resembled "a sheet of flame." So effective was Houston's gunnery, that the Japanese succeeded in making only one hit •—on Mauna Loa. Two men were wounded—one of whom later died.
In the meantime, a lightning-quick thrust by the Japanese resulted in the fall of Timor. Its mission thus aborted, the Allied convoy was turned back to Port Darwin, where it arrived on the 18th.
The return of the convoy had strained the port facilities, as its premature return had not been expected. Thus, Port Darwin, primitive in terms of port facilities and communications but singularly important as the northernmost Allied base of any size on the Australian continent, lay as an inviting target to the rampaging Japanese.
Accordingly, a heavy air strike arrived over Darwin on the morning of 19 February. Allied sources claim that some 108 enemy planes took part in the raid; Japanese records state that the number was 188— the entire air group strength of four Japanese carriers under the command of Vice Admiral Chuichi Nagumo. The attackers scattered the defending P-40 fighters and, unhampered by relatively ineffective gunfire from the ships and port defense guns, laid waste to much of the port, sinking eight ships and damaging nine. Mauna Loa was struck by two bombs which broke her back. The crew abandoned ship without loss, leaving her to sink in Darwin harbor
West Conob (SP-4033) in the color scheme of her postwar mercantile service