Initially, Allied planners had intended to launch the operation on 15 May; however, delays in concentrating logistics and shipping assets resulted in the Allies postponing the operation by several days. Nevertheless, the necessity to conform with plans in the central Pacific meant that it could be carried out no later than 17 May, with operations to capture Biak scheduled to take place 10 days later using most of the same landing craft. The beach frontage on Wakde was considered too narrow to support a full regimental combat team; as a result, it was decided to carry out the operation in three phases. The first phase would entail a landing on the mainland opposite the islands. This would be followed in phase two by a "shore-to-shore" operation across the bight to capture Insoemanai, to secure a base of fire to support the final phase of the assault on Insoemoar. The main combat forces assigned to the Wakde–Sarmi operation were drawn from Brigadier General
Jens A. Doe's
163rd Regimental Combat Team, consisting of 7,800 men, of which about 1,500 took part in the landing on Wakde. This unit had previously taken part in the
Landing at Aitape and had been relieved there by the
32nd Infantry Division on 4 May. After embarking at Aitape on 15 May, the troops were initially transported to Hollandia on 16 May in preparation for the operation. Meanwhile, Allied aircraft mounted airstrikes around the target area throughout late April and into May. The naval forces assigned to the operation were detached from
Rear Admiral William Fechteler's
Task Force 77. These forces were designated the Eastern Attack Group and were commanded by Captain Albert G. Noble, and consisted of three fire support groups, with two heavy cruisers, three light cruisers and 20 destroyers. Fourteen other support vessels were allocated included minesweepers, submarine chasers and several landing craft armed with rockets. The landing craft carrying the assault troops were operated by the 542nd Engineer Boat and Shore Regiment, of the
2nd Engineer Special Brigade. The pre-invasion naval bombardment allocated to support the first phase of the operation involved two cruiser forces: Task Force 74 and Task Force 75. The first force was commanded by British Rear Admiral
Victor Crutchley, and consisted of four Australian ships – the
cruisers Australia and
Shropshire and the
destroyers
Warramunga and
Arunta – and two US destroyers,
Mullany and
Ammen. Task Force 75 was commanded by US Rear Admiral
Russell Berkey, and consisted of the cruisers
Phoenix,
Boise and
Nashville. While Crutchley's force shelled the mainland around Sawar and Sarmi, Berkley's ships hit Wakde. Ten destroyers under Captain Richard Stout also fired upon targets between Toem and Maffin Bay. Early on 17 May, after a fifty-minute bombardment, three battalions from the 163rd Infantry Regiment were landed at a beachhead on the mainland around Arara, to the east of the Tor River. Overhead a force of Allied fighters and medium bombers stood ready to provide close air support, but Japanese resistance was light, consisting of only rifle fire. The 3rd Battalion established the beachhead and then secured the western flank while the 2nd Battalion pushed east towards Tementoe Creek. These two battalions secured the coast and would later undertake heavy fighting during the
Battle of Lone Tree Hill; meanwhile, a small force of heavy weapons troops built around a company from the 641st Tank Destroyer Battalion occupied Insoemanai. The 1st Battalion was held back around Toem, with orders to be prepared to undertake the landing on Wakde Island around the following day. The British-led
Eastern Fleet attacked
Surabaya in the Japanese-occupied
Netherlands East Indies on 17 May as a diversion from the landing at Wakde. This attack, which was designated
Operation Transom, was undertaken by aircraft flying from an American and a British aircraft carrier. The raid did not have any effect on the Japanese military's deployments as the Eastern Fleet was not seen as a serious threat. ==Battle==