Catapult

1. Essex class aircraft carrier
   USN developed 46m long of new H-4B hydraulic catapult which could accerate 13t of aircraft at 145km/h(40.2m/s). The catapult worked at 1 rpm. This was not in time the first Essex till Dec 1942. The catapult pulled a F4U loading VAR rockets, 1,000lb bomb and additional fuel tank in the end of the Pacific War. The total weight of the F4U was 3 times of a Zero loading empty!
   Gunzo p85, No76

2. Eye of fleet
   

   Tone steamming out from Hashirajima to Midway

   IJN used seaplanes for searching the enemy. a E13A1(Jake) of Aichi ejected from IJN heavy cruiser Tone, scouted Pearl Habor air attack before 30 minutes and informed the weather. Tone class contained 5 or 6 seaplanes. Tone always acted with a kido-butai(fast aircraft carriers strike group) at the battles of Indian Sea, Coral Sea and Midway etc.
   The photo shows Tone's steamming out from Hashirajima in Japan to Midway. At the Midway battle, The kido-butai launched 7 scouts including 2 torpedo planes from IJN aircraft carrier Akagi and Kaga, Tone and Chikuma ejected 2 Jakes each, battle cruiser Haruna also ejected a Type 95(sea biplane). The Jake called No.4 from Tone was late a little to eject because a catapult did not work well. No.4 found USN task forces after all. Admiral Nimitz said, 'If the report will be done 30 minutes early, ...' I show specifications of the catapult. I suppose it was developed at the IJN Kure Arsenal.

   Catapult Kure type 25	TBF hooking wires

   • Name : Kure Type 2 model 5
   • Method : gunpower propelled
   • Length : 19.4m(63.8ft)
   • Rail span: 1.2m(3.9ft)
   • Ejecting velocity : 28m/s(31y/s) or 56kt
   • Ejecting weight : 4 ton

3. Escort carrier
   4 escort carriers ferried aircraft to Okinawa in 1945. Okinawa battle was the last large scale air combat of IJN. USS White Plains (CVE-66) steamed to within 100 miles of the island to launch two squadrons of Marine Corps F4U Corsairs for duty there. USS Hollandia (CVE-97), USS Sitkoh Bay (CVE-86), and USS Breton (CVE-23) enrolled the ferry mission.

   USN had developed hydraulic catapults for years. USN applied them for escort aircraft carriers which ran at max speed 18-20kt, could launch a TBF weighing 8.2 ton at WWII. A site shows beautiful photos of ejecting sea biplanes from USS Colorado etc.

4. Submarine
   

   Seaplane E9W1

   IJN was very eager that submarines equip a seaplane. So IJN developed catapults for submarines which were water proof and smaller. But the lenght of the catapults were longer because of weight of new seaplanes. The table shows specifications of catapults for submarines. These catapults were pneumatic.
   Kimata, p221, p226, p236, p241
   Yokosuka E14Y
   Aichi M6A
   Watanabe E9W
   96-siki kogata suijyou teisatsuki(E9W1)
   Catapult
   I-7 gata sensuikan

   Type	Length	Seaplane	Max load	Submarine
   Kure Type 1 model 3	-	Watanabe E9W1	-	I-7
   Kure Type 1 model 4	19m	Yokosuka E14Y	1.6t	I-8, I-15
   Kure Type 1 model 10	26m	Aichi M6A	5t	I-400, I-13, I-14

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