The men of Company D, Shore Battalion, 592nd Engineer Boat and Shore Regiment had their Christmas dinner of roast turkey on 25 December 1943 at Finschhafen, then at 14:15 boarded landing craft for the 105-mile run north to an island they had been told might or might not be held by the Japanese. The island itself was stranger than most maps suggested. Long Island is a collapsed volcanic caldera about fourteen miles across, its interior nearly filled by Lake Wisdom - a freshwater lake five hundred feet above the sea, with an active volcanic cone rising from its center. When the first wave came ashore at Malala village at 02:00 on 26 December, wet from capsized rubber boats, there was no one waiting to shoot at them. The Japanese garrison had already left. What followed was one of the quietest amphibious landings of the Pacific War, and, for a few weeks, the furthest Allied advance into enemy-held territory.
Long Island sits at the northern end of the Vitiaz Strait - roughly circular, about 14 miles in diameter, 160 square miles of rainforest and volcanic rock. Two peaks rise from its rim: Mount Reamur in the north at 4,278 feet, and Cerisy Peak in the south at 3,727 feet. Between them lies Lake Wisdom, one of the largest lakes in Papua New Guinea, filling the flooded caldera of the volcano that made the island. An active cone called Motmot rises from the lake's center. In 1660 the volcano produced what scientists now call the third-largest eruption of the last 2,000 years - a Plinian blast more powerful than Krakatoa in 1883, burying the entire island under 30 meters of volcanic ash. The island had once supported a larger population than it did in 1943. That population had died in the 1660 eruption, or had left. By the time Allied forces arrived, only about 250 people lived at two villages: Bok in the southeast and Malala in the northeast.
Long Island mattered because of what passed around it. Japanese barges carrying troops and supplies from Rabaul to the New Guinea fighting fronts used the island as a staging point, anchoring in its sheltered bays during daylight hours and running again by night. Allied commanders wanted that staging point silenced. They also wanted the island's 4,000-foot elevation for a radar station - one that could cover the upcoming landing at Saidor and provide warning of Japanese aircraft coming south from Wewak and Madang. On 6 October 1943, a party of three Australians from the Allied Intelligence Bureau and four Solomon Islanders, the coastwatcher teams that quietly kept the Pacific War lit, went ashore by PT boat. Their job was to watch, count aircraft, and report by radio. The coastwatchers found at least two Japanese parties on the island when they arrived. By November, they reported, the Japanese had left. The island was unoccupied.
On 22 December 1943, Lieutenant General Walter Krueger, commander of Alamo Force, issued Field Order No. 8, directing the 2nd Engineer Special Brigade to seize Long Island. The operation was codenamed Sanatogen and was timed to coincide with the landings at Cape Gloucester on New Britain. That same day, elements of the 2nd Engineer Special Brigade began moving from Oro Bay to Finschhafen. By 25 December, a force of 220 men had gathered - 150 assault troops from Company D of the 592nd EBSR, 35 men of the Boat Battalion to handle the landing craft, and 35 Royal Australian Air Force personnel from No. 338 Radar Station under Pilot Officer Alan Lum, who had flown in from Port Moresby airfields in 11 transport aircraft. A rehearsal on 24 December was cancelled because of an air raid alert. The final briefing came at 08:30 on Christmas Day. Boats were loaded by noon. The men ate roast turkey. Then they went to war in a convoy that would not, as it turned out, find any war waiting.
Three PT boats carrying 90 men of Company D set out from Finschhafen at 18:00 on Christmas Day. The landing craft - three LCVPs and five LCMs - had set out at 14:15 and were making their slower way along the coast in broad daylight, unmolested by Japanese aircraft. The PT boats overtook the landing craft in the darkness and arrived off Malala at 23:45, fifteen minutes late. There was no preliminary bombardment because there was no enemy to bombard. The 90 assault troops transferred to six rubber boats - a maneuver made harder by the fact that the rehearsal had been cancelled. Two boats capsized in the surf. No one drowned. No equipment was lost. By 02:00 on 26 December the first wave was ashore. The second wave arrived 80 minutes late at 05:20, the sun not yet up. Two LCMs tried to beach and broached in steep surf, soaking radar equipment in salt water. The crews searched, found a better beach south of Cape Reamur, and by 13:00 had unloaded a hundred tons of equipment including a bulldozer, two jeeps, two 37 mm guns, bazookas, mortars, and the fragile radar sets that were the whole point of the operation.
On 27 December the Australians moved their radar equipment to a 150-foot hilltop on the east coast, towing 1,700-pound generators on sleds up the ridge. The equipment, briefly dunked in salt water on arrival, now had to contend with heat, humidity, and a wet season that was just beginning. It failed often. Replacement power supplies and transmitters arrived on 27 January 1944. By April the Allied advance had reached Madang, and the main Japanese air threat now came from Wewak further north - out of radar range from the east coast of Long Island. No. 338 Radar Station was ordered to move to Matafuna Point on the west coast. It took a week. A flying fox cable cableway was rigged to lower the equipment back down to sea level. The station went operational again at 19:00 on 11 April 1944 and stayed on the air until 28 January 1945. The garrison was, for a time, the furthest Allied position in the theater. Brigadier General William F. Heavey, who commanded the engineer brigade, was reportedly surprised when the capture was announced at all. The engineers built defenses, camps, and a 1,500-foot airstrip for Piper Cub aircraft in five days. Rumors ran through the garrison that the Japanese might try to retake the island. They never did. They had already accepted the loss of their staging point. On 17 February 1944 the main 592nd EBSR party left Long Island. Krueger, in his orders, praised them for aggressiveness and superior seamanship in accomplishing their mission against unusual odds - a mission in which no shot was fired.
Long Island is centered near 5.35 degrees south, 147.12 degrees east, at the northern end of the Vitiaz Strait in the Bismarck Sea. Recommended viewing altitude: 6,000-8,000 feet to see the full caldera rim, Lake Wisdom in the interior, and the active cone of Motmot rising from the lake's center. There are no airfields on the island today. The nearest airports are Madang (AYMD) to the southwest on the New Guinea mainland, Nadzab/Lae (AYNZ) to the south, and Hoskins (AYHK) to the east on New Britain. The island is surrounded by 1,000-2,000 meters of water and has no sheltered all-weather harbors. Expect cumulus buildup by midday and frequent squalls; the 1660 caldera eruption is a reminder that this is an active volcanic system.