Partials/Opening ASW

The opening anti-submarine attack (OASW) can be performed by any ship with displayed ASW value of 100 or greater (ship's ASW stat + any equipment ASW stats, not counting equipment improvements) and at least one sonar.

• Isuzu Kai Ni, Tatsuta Kai Ni, Jervis Kai, Samuel B. Roberts Kai, and Johnston can always perform OASW, even with less than 100 displayed ASW or without any ASW equipment.
• Taiyou, Shinyou, Gambier Bay, and Zuihou Kai Ni B can perform OASW with 1+ planes with 7 ASW stat equipped and a total displayed ASW of 65 or greater. For Taiyou and Shinyou Kai and Kai ni the bombers are not required, 65 displayed ASW is sufficient (however, if she is not using a torpedo or dive bomber with ASW stat, she will be able to perform OASW attack but will be unable to perform ASW attacks in the shelling phase). OASW attacks will be performed even if she is at medium damage or all her planes were shot down.
• Coastal Defense Ships can perform OASW with displayed ASW of 60 or greater. With displayed ASW of 75 or greater and equipment ASW of 4 or greater they can perform OASW without a sonar equipped.
• Hyuuga Kai Ni can perform OASW even with less than 100 displayed ASW if she is equipped with at least 2 autogryos
  
  OR at least 1 helicopter
  .
• If several ships fulfill the requirements, then they all can perform preemptive attacks, each attacking a random submarine in the enemy fleet. The firing order is determined by the range order, similar to the First Shelling Phase. The order for ships of the same range is random.
• The damage follows the usual ASW formula and is affected by the usual modifiers (formation, engagement, health, ammo), as well as equipment improvements.The following tables show how much base ASW is needed (in form of required ship level) to enable OASW with a given equipment setup (T4: Type 4 Passive Sonar, T3: Type 3 Active Sonar, DC: Type 3 Depth Charge Projector).

Enemy Ships with OASW

Destroyer

• Ni-Class Late Model Flagship

Light Carrier

• Nu-Class Elite (III, IV), Kai Elite and Kai Flagship

DD
Ship	3 Slots					2 Slots				1 Slot
	T4/T4/T4 36 + 64	T4/T4/T3 34 + 66	T4/T4/DC 32 + 68	T4/T3/DC 30 + 70	T3/T3/DC 28 + 72	T4/T4 24 + 76	T4/T3 22 + 78	T4/DC 20 + 80	T3/DC 18 + 82	T4 12 + 88	T3 10 + 90
Asashio K2D	85									97	102
Libeccio Kai Maestrale Kai	60	65	70	75	80	90	95	99	104	119	124
Satsuki K2	75			78	82	90	94	98	101	113	117
Fumizuki K2	77			78	82	90	94	98	101	113	117
Asashimo Kai	66	70	75	79	84	93	97	102	106	120	124
Shigure K2	74	78	82	87	91	99	104	108	112	125	130
Ushio K2	74	79	83	88	93	102	106	111	116	129	134
ВерныйВерный	77	81	86	90	95	104	108	113	117	131	135
Akizuki Kai Teruzuki Kai Hatsuzuki Kai	81	85	90	95	99	109	114	118	123	137	142
Harukaze Kai	84	88	92	96	99	107	111	115	119	131	135
Matsukaze Kai	88	92	96	99	103	111	115	119	123	135	139
Kamikaze Kai	87	91	95	99	104	112	117	121	125	138	143
Yuudachi K2 Murakumo K2 Hatsushimo K2 Mutsuki K2	87	92	97	102	107	116	121	126	131	145	150
Hatsuharu K2	87	92	97	102	107	117	122	127	132	148	153
Kisaragi K2	88	92	97	102	107	116	121	125	130	144	149
Fubuki K2	90	95	99	104	109	118	123	128	132	147	151
Kasumi K2	90	95	99	104	109	119	124	129	134	149	154
Asakaze Kai	92	96	99	103	107	115	119	123	127	139	143
Akatsuki K2	94	99	105	110	115	126	131	136	141	157	162
Ooshio K2	99	105	110	115	120	131	136	141	146	162	N/A
Ayanami K2 Kawakaze K2	102	107	113	118	123	133	139	144	149	165	N/A
Arashio K2	114	120	126	132	138	150	156	162	N/A	N/A	N/A
Shimakaze Kai Yukikaze Kai	115	121	127	134	140	152	158	164	N/A	N/A	N/A

CL/CLT
Ship	3 Slots					2 Slots				1 Slot
	T4/T4/T4 36 + 64	T4/T4/T3 34 + 66	T4/T4/DC 32 + 68	T4/T3/DC 30 + 70	T3/T3/DC 28 + 72	T4/T4 24 + 76	T4/T3 22 + 78	T4/DC 20 + 80	T3/DC 18 + 82	T4 12 + 88	T3 10 + 90
Naka K2	48	49	54	59	65	75	81	86	91	108	113
Kinu Kai/Kai Ni	52	58	64	71	75		80	86	91	108	113
Yura Kai/Kai Ni	52	58	64	71	77	79	85	91	97	114	120
Tama Kai Ni	70				72	84	87	92	97	112	118
Abukuma Kai/Kai Ni	52	58	64	71	75	82	88	94	99	117	123
Sakawa Kai	63	66	70	74	77	85	88	92	96	107	110
Kiso K2	65	68	72	76	80	88	92	96	99	111	115
Agano Kai Noshiro Kai Yahagi Kai	68	71	75	78	82	89	92	96	99	110	114
Jintsuu K2	60	65	70	75	80	90	95	99	104	119	124
Kitakami K2 Ooi K2	71	75	79	82	86	94	98	101	105	117	120
Kuma Kai Tama Kai Natori Kai	72	76	80	83	87	94	98	101	105	116	119
Sendai K2	72	77	83	88	94	105	110	116	121	138	143
Tenryuu Kai Ni	87	91	95	99	105	113	118	122	126	139	144

4 Slots CL/CT/DD
Ship	4 Slots
	T4/T4/T4/T4 48 + 52	T4/T4/T4/T3 46 + 54	T4/T4/T4/DC 44 + 56	T4/T4/T3/DC 42 + 58	T4/T3/T3/DC 40 + 60	T3/T3/T3/DC 38 + 62
Tashkent Kai	50	50	50	54	60	66
Yuubari Kai Kashima Kai	62	66	71	75	80	84
Katori Kai	75	80	85	90	95	99
Ooyodo Kai	132	138	143	148	153	158
Ship	3 Slots
	T4/T4/T4 36 + 64	T4/T4/T3 34 + 66	T4/T4/DC 32 + 68	T4/T3/DC 30 + 70	T3/T3/DC 28 + 72
Tashkent Kai	72	78	84	90	96
Yuubari Kai Kashima Kai	88	93	97	102	106
Katori Kai	104	109	114	119	124
Ooyodo Kai	163	N/A	N/A	N/A	N/A
Ship	2 Slots				1 Slot
	T4/T4 24 + 76	T4/T3 22 + 78	T4/DC 20 + 80	T3/DC 18 + 82	T4 12 + 88	T3 10 + 90
Tashkent Kai	108	114	120	126	144	150
Yuubari Kai Kashima Kai	115	119	124	129	141	146
Katori Kai	134	139	144	149	164	N/A
Ooyodo Kai	N/A	N/A	N/A	N/A	N/A	N/A

See Also

• Opening ASW calculations by SpFire