Navy and Army Air Force: The Division's Z-Day on Biak

by Dr. Hargis Westerfield, Division Historian

           This is the fine story of our Navy and Army Air Force's fight for our 41st Infantry Division before and through Z-Day on Biak. Few 41st riflemen and cannonneers realize that the Army Air Force was blasting the Jap garrison's build-up long before Z-Day. Few of us realize the hazards our Navy endured to land our first cumbrous convoy of troops and supplies. This is only a part of the story of how Air Force and destroyers grappled with Jap raiders from the skies.

On 28 April, long before our beachhead of 27 May, 47 B-24s hit Mokmer Drome in their first daylight strike against Biak. They shot down three of 12 Jap fighters, killed 13 grounded planes. On 4-7 May, three bombing convoys fought air-battles over Biak. They lost a Liberator and had to crash-land another back at Hollandia.


On 7 May, our bombers killed two Jap planes; our fighters claimed eight planes downed. Soon, the Japs quit intercepting bombers, but for an attempt of 16-18 fighters on 15 May. Then seven of their planes fell to our fighters. (Jap Ack Ack did shoot down a B-24 on 12 May.)


Then five heavy bomb groups attacked - 99 planes on 17 May against Mokmer and Sorido Strips and Bosnek Village. On 23 May, our fighters silenced a Mokmer Ack Ack position and sank four barges offshore. Our raids had long ago become daily. Our Air Force claimed destruction of 90 percent of the supply dumps near the three Strips and Bosnek Village.


Bosnek was originally the 222 Infantry Regiment's main supply and bivouac area, but by 23 May, our bombers had expelled most of the infantry. Other airmen were battering Nippo bases on Noemfor, Halmahera, and the New Guinea mainland to prevent planes from smashing our Biak invasion.


Rear-Admiral William Fechteler's Hurricane Task Force left Hollandia for Biak with our 41st Division on the night of 25 May. Fechteler worried greatly about how to protect his slow, unwieldy convoy 325 miles from Hollandia to Biak. He had to go slow because he had to pull eight heavy LCTs ("tank landing crafts") which we needed to surmount the coral reef before Bosnek with heavy loads of tanks and field artillery.


Each of eight LCTs carried a medium tank, two 105 cannon, two bulldozers, two dump-trunks, and a communications jeep. Fechteler hoped to drive the eight LCTs over the reef. He hoped that they would then find water enough to bear them inshore. So important was their cargo that we had to accept danger of damage on that coral reef.


Eight slow LSTs had to tow those eight LCTs. So five cruisers, 22 destroyers, five Assault Transports, 28 LCls and other ships all had to amble at just 8.5 knots (9.775 miles per hour). Probably this slow convoy had no chance to evade Jap detection, and therefore took the most direct route to Biak. But despite radar spotting of a few Jap planes, the convoy traveled the night of 25 May, all day 26 May, and all night 26 May without Jap interference.


Shortly after 0550 in the first light of 27 May, Hurricane Task Force stood up before Biak, ready to fight. An unexpectedly strong current had caused it to arrive at 0629, 15 minutes before the scheduled H-Hour. At once Adam Fechteler ordered, "Execute landing plan!"
      But Army Air Force probably struck first on D-Day. As soon as they could see Bosnek targets, 12 B-24s dropped their bombs. At 0700-0704, 25 more B-24s dropped 234 500-Ib bombs on our "Green Beaches" before Bosnek, but left the two jetties intact. Although XIII Bomber Command on Los Negros assigned 48 planes to this mission, Bomber No. 26 crashed and exploded on the runway and blocked off the last 22. Another crashed at sea. (Between 1103 and 1150, 77 more Liberators would hit the Mokmer area, after debarkation was well under way. Some time that day, Jap Ack Ack shells shot down a fighter A-20 and killed its gunner.)


The air-bombing was effective. Alamo Force Headquarters even credited these Z-Day raids with destroying a 5-inch and 23-inch dual purpose guns halfway between the two Bosnek jetties. But with the Navy blasting at the same time, we cannot be sure whether Air Force or Navy made these important kills.


While the first bombers struck, our Navy was losing a 45-minute pre-landing shelling of Biak. Far west, cruisers Phoenix, Boise, and Nashville began throwing 1,000 6-inch shells into the Strips. Two minutes after firing started, Destroyer Hutchins got orders to shoot at a fast-moving motor boat. Firing close inshore, Hutchins took a 4.7 inch shell from a concealed battery on Mokmer Ridge - probably the guns that 186 Infantry found silenced when it closed the Great Gap on 16 June. The shell struck Hutchins' foremast. It failed to detonate, but penetrated the radar room. It made a four-foot hole topside and wounded three men.


Hutchins withdrew to assess damages; the Jap motorboat was forgotten. Destroyer Bache drove inshore to fight the battery. It returned fire, but missed Bache. After repairs, Hutchins returned at 1300 and venomously arced 32 three-gun salvos into the 4.7 area. Hutchins drew no return fire; the Jap battery fought again next day.


While the cruisers blasted the Strips to the west, our destroyers cleared Bosnek Foreshore in preparation for 186 Infantry's landing. Closing in firing from range 4,000 yards lessening to 1,500 yards, five destroyers threw in 2,500 five-inch shells. After 15 minutes, four other destroyers replaced the first five. For 27 minutes, this four shot 2,400 five-inch rounds into the Japanese coast.


Three minutes before H -Hour, the destroyers ceased fire. Already overside in tracked amphibious craft for climbing the reefs, 186 Infantry peered into the curtain of smoke 500 yards off that concealed the beaches.


Five waves of 186 Infantry drove for the beach – three waves of tracked landing vehicles (LVTs or Buffaloes) in the lead.


Two waves of amphibious trucks (DUKWs or Ducks) charged after the LVTs. Two rocket-armed LCIs (Infantry Landing Craft) flanked our five waves and slashed into Biak to cover us.


About 500 yards out, Jap heavy machine guns and mortars flailed at LCI-31 on our left flank. No. 31, rocketed back and silenced the Japs. By 0719, 186's first wave of LVTs beached their men; and four other waves roared in after it.


Then the Navy Commanding Officers got alarming information, from Commander Day in a third LCI- Day whose duty was to find suitable beaching points for LCls and LCTs. Day could not find Bosnek Jetties; the first five waves were grounding under a steep and unknown coast.


        From his control ship, Captain Anderson ordered Wave No. 6 to hold up. While these DUKWs milled around, he told Destroyer Kalk to find the jetties by radar.


Kalk reported that Bosnek Jetties were two miles eastward. Our 186's 2nd Battalion was ashore in a mangrove swamp 3,000 yards west of Bosnek Beaches. The I and K Companies landed in the edge of that swamp, 700 yards east of 2nd Battalion but 2,300 yards west of Bosnek. Mission of these outfits had been to clear Bosnek Foreshore of Japs; but our Navy had diverted them far away from that crucial mission of covering the main landing. We were lucky that the Japs did not aggressively garrison that foreshore.


It was lucky also for the isolated 186 outfits in the mangrove swamp, that the Ibdi Pocket Japs did not make a downhill attack. And 20 minutes after Kalk found Bosnek Jetties by radar in the smoke, Captain Anderson loosed Wave No.6 in the right direction.


Destroyer Hobby marked East Jetty with a white phosphorus shell; the landing barges changed direction. After a preparatory fire of 350 round of Hobby's 40 mm guns. LCPRs beached with 3rd Battalion men who secured the jetties at 0800. Unloading of men and supplies began at once.


Now the misplaced 186 outfits scrambled east to Bosnek, and 162 Infantry landed at the Jetties on the way to Parai Defile and cut through the 186 men. Confusion increased as 186's "I" and "K" men crossed before 2nd Battalion moving from the swamps. To complicate the regroupment even more, field artillery and Task Force reserves poured out on the Jetties among 186 men. Not until 1200 had 186 Infantry secured the Bosnek area. But the Japs failed to attack, although a platoon of 2nd  Company 222 Infantry held Bosnek Ridge.


Were the Naval officers fully responsible for 186' s near disaster? Their excuse was that smoke of the bombings had masked the landmarks. But they had warning from the unexpected current that pressed them to arrive off Biak 15 minutes before the scheduled landing. Warning was also in Terrain Handbook 27, (Allied Geographical Section), that the current off South Biak could attain three knots. (Naval historians report that the Z-Day speed of the current was 2-3 knots.)


Perhaps the Handbook, dated 12 May 1944, was not available to the Navy by 27 May. But if Destroyer Kalk could easily find Bosnek Jetty by radar, why did the Navy fail to fix radar observation on the Jetty all the time? The Navy does seem at fault in the Biak landing of 27 May 1944.


Having promptly corrected its error about the current, the Navy did well. That morning, an unnamed destroyer sank six Jap barges west of Bosnek; east of Bosnek, another destroyer hit supply dumps and Japs in caves. Cruisers and destroyers hammered the Strips until 1700.


Most of the morning, the 41st lacked fighter cover for Jap bombers. After four B-25s' patrol of early morning, bad weather cut off the next two patrols from Wakde. But guns of 208 AckAck Group quickly landed and guarded our skies.


      First Jap attack came about 1400, with our fighters now above. Our P-47 squad caught eight Jap fighters charging low over the sea east of Biak, killed five planes, lost a P-47.


Second two attacks really endangered crowded Bosnek Beach. Too low for radar detection, two fighter-bombers dived over Bosnek Cliff at perfect targets - four LSTs unloading side by side on West Jetty. Admiral Fechteler had risked these LSTs because of their importance in the only good place.


LST-456 took 2-3 small bombs on the deck. Dropped too low to arm in time, they were duds - cracked open on the deck, and spilled yellow powder to sweep up. These two Jap planes strafed the beach, killed one Navy man, wounded two more. Bombs on the beach were duds; our fighters drove off the Japs.


Then four twin-engine planes dived over Bosnek Cliff - low and down in the sun. From Navy and Army guns already sighted on the cliff, intense anti-aircraft fire slashed them.


Two bombers flamed up and crashed. Another fled off in smoke close inshore. Flaming No. 4 Plane pointed for Destroyer Sampson, Admiral Fechteler's flagship. Anti-aircraft fire clipped a wing; it missed Sampson. Its wing-tip hit the water 400 yards away.


But it hit just 20 yards from Sub-Chaser SC 699 which had a wooden hull. The plane's engine penetrated the hull near the water-line. Came the explosion; flames mast-high covered all SC-699. Many crewmen found themselves in the water - unknowing whether they had jumped or had been blasted in.


Rescue Tug Sonoma rushed to pick up survivors. While SC-699' s Commander Holt helped man the fire-hose, the surviving men aboard jettisoned drums of exploding ammo. Fire was out in 15 minutes. Only two men were dead, 8-9 wounded. They found William Henry Harrison still crouched in firing position behind his 20 mm gun. He had fought the plane until it hit the gun and killed him.


Except for raid alerts and necessary breaks, unloading parties worked continuously. All LCTs easily reached the beach to unload, then came out to fasten ramp to ramp with three LCTs unable to reach the crowded jetties. By 1000, the five extremely valuable Assault Transports were in convoy back to Hollandia.


 By 1715, unloading ceased a half hour prematurely because we feared more Jap airmen. Our own fighters must leave to reach Hollandia and Wakde before dark fall. But Jap planes from the west would have 24 minutes' more daylight to strike our vulnerable off-loading. But by 1715, all Task Force troops had landed - 12,000-odd - also 12 medium tanks, five 155 mm howitzers with 12 105s and 121 75s, and 500 vehicles. Some 3,000 tons of supplied landed, with only 300 tons still afloat, on that great Z-Day for our Division.


For Z-Day on Biak, Air Force and Navy did well - with only a few casualties, a few planes lost, and two ships taking heavy blows. Despite handicap of the slow LCTs, no convoyed ship had suffered. Despite deprivation of our fighter cover to 1115, and 24 minutes before sunset, we had little trouble from the air. (Admiral Fechteler emphatically recommended all-day carried cover in all later landings.) Only serious error was the Navy's about the speed of the current off Biak.





CREDIT: I used mostly secondary sources of other historians outside the Army who did the spade-work. Secondary sources are SE Morison's Volume VIII, History of U.S. Naval Operations in World War II, WF Craven and JL Cates' Volume IV, Army Air Forces in World War II, RR Smith's Approach to the Philip- pines; and W Karig, RL Harris, and field artillery Manson's Battle Report/The End of an Empire. (Battle Report seems less reliable.) Primary sources are Rear-Admiral Wm Fechteler's 7 Amphibian Force's Report of Biak Operations (10 May 1944), Biak Journals and Narratives of 186 and 162 infantry, and Allied Geographical Section's Terrain Handbook No. 27 (Schouten Islands, 12 May 1944).