on 29 January, together with the converted carriers and . Each of the three carriers was intended to be equipped with 21 fighters and 9 torpedo bombers, but this plan was changed on 15 February to a consolidated air group, the 653rd, that controlled the aircraft of all three carriers. While fully equipped by May with 18 Zero fighters, 45 Zero fighter-bombers, 18 B5Ns, and 9 Nakajima B6N "Jill" torpedo bombers, the air group's pilots were largely drawn from the two most recent classes and lacked experience. The ship sailed for Tawi-Tawi on 11 May in the Philippines. The new base was closer to the oil wells in Borneo on which the Navy relied and also to the Palau and western Caroline Islands where the Japanese expected the next American attack. However, the location lacked an airfield on which to train the green pilots and American submarines were very active in the vicinity which restricted the ships to the anchorage. Battle of the Philippine Sea The 1st Mobile Fleet was en route to Guimares Island in the central Philippines on 13 June, where they intended to practice carrier operations in an area better protected from submarines, when Vice Admiral Jisaburō Ozawa learned of the American attack on the Mariana Islands the previous day. Upon reaching Guimares, the fleet refueled and sortied into the Philippine Sea where they spotted Task Force 58 on 18 June. The Americans failed to locate Ozawa's ships that day and the Japanese turned south to maintain a constant distance between them and the American carriers as Ozawa had decided on launching his air strikes early the following morning. He had deployed his forces in a "T"- shaped formation with the 3rd Carrier Division at the end of the stem, ahead of the 1st and 2nd Carrier Divisions that formed the crossbar of the "T". Zuihō and her consorts were intended to draw the attentions of the Americans while the other carriers conducted their air strikes without disruption. The first wave of search aircraft spotted one group of four carriers from Task Force 58 at 0734 and the Japanese carriers launched their aircraft an hour later. This consisted of 43 Zero fighter-bombers and 7 B6Ns, escorted by 14 A6M5 fighters; the carriers retained only three fighters, two fighter-bombers, two B6Ns and two B5Ns for self-defense and later searches. While the air strike was still forming up, the