Combat/Opening Anti-Submarine Warfare

Introduction

During the opening phases of combat, ships which meet certain requirements are able to perform opening ASW attacks. These attacks are valuable because they have the opportunity to sink submarines before they get the chance to perform opening torpedoes.

Overview

1. All ships with an ASW stat are capable of performing OASW.

• Theoretically any ship capable of ASW is able to perform OASW but no equipment exists that allows normal CVL, CAV and BBV to hit the 100 ASW threshold.

2. Upgrades to ASW equipment are not counted towards the thresholds for triggering OASW.

3. OASW attacks are performed in range order.

• Attacks from ships with the same range are random.

4. Damage is calculated the same way as normal ASW.

5. You can modernise a ship's ASW using destroyer escorts. Please see Modernization for more details.

Trigger Requirements

Ship	Requirement
All ASW capable ships	ASW ≥ 100
Destroyer Escorts	Either: ASW ≥ 60 with ASW ≥ 75 with equipment that has 4≤ ASW
Isuzu Kai Ni Tatsuta Kai Ni Jervis Kai Janus Kai Samuel B. Roberts Kai Fletcher Johnston Yuubari Kai Ni D	Default OASW regardless of ASW stat or equipment.
Taiyou Shinyou Gambier Bay Zuihou Kai Ni B	Have both: ASW ≥ 50 At least 1 with ASW ≥ 7, , or
	Have both: ASW ≥ 65 At least 1 with ASW ≥ 7, , or
	Have both: ASW ≥ 100 At least 1 or with an ASW stat.
Taiyou Kai/Kai Ni Shinyou Kai Kai Ni	ASW ≥ 65
Light Carriers (Except Suzuya and Kumano)	ASW ≥ 50 (Large SONAR only) At least 1 with ASW ≥ 7, , or
Hyuuga Kai Ni	Either: 2 Autogyros 1 Helicopter

Minimum OASW Level

The minimum level for OASW can be calculated using:

[math]\displaystyle{ \text{Level}_\text{min} = \bigl\lceil \left( \left(\text{OASW}-\text{ASW}_\text{equip} \right) - \text{OASW}_\text{min} \right) \times \frac{99}{\text{OASW}_\text{max}-\text{OASW}_\text{min}} \bigr\rceil }[/math]

• [math]\displaystyle{ \text{OASW}_\text{min} }[/math] is the minimum ASW of the ship as noted in the tables below.
• [math]\displaystyle{ \text{OASW}_\text{max} }[/math] is the maximum ASW of the ship as noted in the tables below.
• [math]\displaystyle{ \text{ASW}_\text{equip} }[/math] is the total base ASW provided by equipment.
• [math]\displaystyle{ \text{OASW} }[/math] is the relevant OASW threshold.
  • [math]\displaystyle{ 60 }[/math] for DEs with sonars.
  • [math]\displaystyle{ 75 }[/math] for DEs without sonars and ASW equipment that have ASW ≥ 4.
  • [math]\displaystyle{ 65 }[/math] for CVLs with ASW > 7 planes OR Taiyou/Shinyou Kai/Kai Ni
  • [math]\displaystyle{ 100 }[/math] for all other ships.

Minimum OASW Chart

The following apply to the tables below:

• Only easily obtainable equipment combinations are shown.
• The equipment abbreviations are:
  • T4S: Type 4 SONAR
  • T3S: Type 3 SONAR
  • T3DCP: Type 3 Depth Charge Launcher
  • T2DC: Type 2 Depth Charge
  • 931: Type 97 Torpedo Bomber (931 Air Group)
• Ships with default ASW as detailed in the section above aren't listed.
• Numbers in brackets are the total ASW of the equipment setup.
• Only the top remodel is applicable unless otherwise stated.
• If you require minimum OASW levels for remodels or equipment combinations that aren't listed, you can use the formula above and minimum and maximum ASW stats on the ship girl pages.

OASW Tables

All ships are presumed to be of the highest possible remodel unless otherwise stated

Destroyers

Ship	Min ASW	Max ASW
			3 Slots					2 Slots			1 Slot
			T4S/T4S/T4S (36)	T4S/T4S/T3CP (32)	T3S/T3S/T3S (30)	T3S/T3S/T3DCP (28)	T3S/T3DCP/T2DC (25)	T4S/T4S (24)	T3S/T3S T4S/T3DCP (20)	T3S/T3DCP (18)	T4S (12)	T3S (10)
Asashio K2 D	45	89	85	85	85	85	85	85	85	85	97	102
Urakaze D	45	88	69	69	69	69	70	72	81	86	99	104
Tanikaze D	44	86	70	70	70	70	74	76	85	90	104	109
Maestrale Libeccio	40	80	60	70	75	80	87	90	99	104	119	124
Grecale	38	79	63	73	78	83	90	92	102	107	121	126
Shiratsuyu K2	30	83	77	77	77	79	85	86	94	98	109	113
Arare K2	33	81	64	73	77	81	87	89	97	102	114	118
Umikaze K2	28	82	82	82	82	82	87	88	96	99	110	114
Satsuki K2	30	81	75	75	78	82	88	90	98	101	113	117
Fumizuki K2	30	81	77	77	78	82	88	90	98	101	113	117
Asashimo	35	79	66	75	79	84	90	93	102	106	120	124
Shikinami K2	30	79	69	77	81	85	91	93	102	106	118	122
Okinami K2	29	79	79	79	82	86	92	94	101	105	117	121
Kazagumo K2	29	78	75	79	83	87	93	95	104	108	120	124
Verniy	30	77	72	81	85	89	95	97	106	110	123	127
Yuugumo K2	30	77	75	81	85	89	95	97	106	110	123	127
Tashkent	40	73	72	84	90	96	105	108	120	126	144	150
Murasame K2	29	77	73	81	85	89	95	97	106	110	122	126
Shigure K2	31	76	73	82	86	91	97	99	108	113	126	130
Ushio K2	32	75	74	83	88	93	99	102	111	116	129	134
Hamakaze B K	32	72	80	90	95	99	107	109	119	124	139	144
Makigumo K2 Kishinami Akizuki Teruzuki Hatsuzuki	30	72	81	90	95	99	107	109	118	123	137	142
Hatsushimo K2	28	72	81	90	95	99	106	108	117	122	135	140
Suzutsuki	28	71	83	93	97	102	109	111	120	125	139	143
Harukaze	22	72	84	92	96	99	105	107	115	119	131	135
Okinami	32	70	84	94	99	105	113	115	126	131	146	152
Kuroshio K2 Isokaze B K	31	70	84	94	99	105	112	115	125	130	145	150
Z1 Zwei Z3 Zwei	37	69	84	96	103	109	118	121	134	140	158	164
Arashi	30	70	85	95	99	104	112	114	124	129	144	149
Kamikaze	24	70	87	95	99	104	110	112	121	125	138	143
Hatakaze	21	70	87	95	99	104	110	112	120	124	136	140
Hatsuharu K2 Yamakaze	30	69	87	97	102	107	115	117	127	132	148	153
Mutsuki K2 Murakumo K2 Yuudachi K2	28	69	87	97	102	107	114	116	126	131	145	150
Matsukaze	20	70	88	96	99	103	109	111	119	123	135	139
Kisaragi K2	27	69	88	97	102	107	114	116	125	130	144	149
Hayanami	26	69	88	97	102	106	113	116	125	129	143	148
Shiranui K2 Naganami K2	30	68	89	99	105	110	118	120	131	136	152	157
Kasumi K2/B Nowaki Hagikaze Akishimo	28	68	90	99	104	109	117	119	129	134	149	154
Maikaze	27	68	90	99	104	109	116	119	128	133	148	153
Fubuki K2	26	68	90	99	104	109	116	118	128	132	147	151
Kagerou K2	30	67	91	102	108	113	121	124	134	140	156	161
Asakaze	18	68	92	99	103	107	113	115	123	127	139	143
Takanami Hayashimo Kiyoshimo	29	67	92	102	107	113	120	123	133	139	154	159
Oyashio	27	67	92	102	107	112	119	122	132	137	151	156
Akatsuki K2 Fujinami	28	66	94	105	110	115	123	126	136	141	157	162
Hamanami	28	65	97	108	113	118	126	129	140	145	161	166
Uzuki	21	65	97	106	111	115	122	124	133	138	151	156
Yamagumo Hatsukaze Akigumo	27	64	99	110	116	121	129	132	142	148	164	169
Ooshio K2 Tokitsukaze	26	64	99	110	115	120	128	131	141	146	162	167
Ayanami K2 Kawakaze K2	25	63	102	113	118	123	131	133	144	149	165	170
Minazuki	19	61	107	116	121	125	132	135	144	149	163	168
Michishio K2	26	60	111	123	129	134	143	146	158	164	-	-
Yayoi Nagatsuki Kikuzuki Mikazuki Mochizuki	18	59	112	121	126	131	138	141	150	155	170	174
Asashio K2 Arashio K2	26	59	114	126	132	138	147	150	162	168	-	-
All other destroyers	24	59	114	125	131	136	145	148	159	165	-	-
Amatsukaze	28	59	115	128	135	141	151	154	167	173	-	-
Yukikaze Shimakaze	27	59	115	127	134	140	149	152	164	171	-	-
Minegumo	24	58	117	129	134	140	149	152	164	169	-	-

Light Cruisers

Ship	Min ASW	Max ASW
			3 Slots					2 Slots			1 Slot
			T4S/T4S/T4S (36)	T4S/T4S/T3CP (32)	T3S/T3S/T3S (30)	T3S/T3S/T3DCP (28)	T3S/T3DCP/T2DC (25)	T4S/T4S (24)	T3S/T3S T4S/T3DCP (20)	T3S/T3DCP (18)	T4S (12)	T3S (10)
Kinu K2	49	86	75	75	75	75	75	75	83	89	105	110
Naka K2	48	85	48	54	59	65	73	75	86	91	108	113
Yura K2	49	83	77	77	77	77	77	79	91	97	114	120
Abukuma K2	48	82	75	75	75	75	79	82	94	99	117	123
Tama K2	43	83	70	70	70	72	80	82	92	97	112	117
Jintsuu K2	40	80	60	70	75	80	87	90	99	104	119	124
Sakawa	30	84	63	70	74	77	83	85	92	96	107	110
Kiso K2	32	82	64	72	76	80	86	88	96	99	111	115
Agano Noshiro Yahagi	26	82	68	75	78	82	87	89	96	99	110	114
Kitakami K2 Ooi K2	27	79	71	79	82	86	92	94	101	105	117	120
Kuma Nagara Natori	24	79	72	80	83	87	92	94	101	105	116	119
Sendai K2	38	74	72	83	88	94	102	105	116	121	138	143
Tenryuu K2	24	70	87	95	99	104	110	112	121	125	138	143
Yuubari	24	69	88	97	102	106	113	115	124	128	141	146
Yuubari Kai Ni	49	83	84	84	84	84	84	84	91	97	114	120
Yuubari Kai Ni Toku	27	70	86	95	99	104	111	113	123	127	141	146
Gotland	38	62	108	124	132	141	153	157	174	-	-	-
Giuseppe Garibaldi	25	60	111	122	128	133	142	145	156	162	-	-
Duca degli Abruzzi	25	59	114	126	132	137	146	149	161	166	-	-
Perth	20	55	125	136	142	148	156	159	170	-	-	-
De Ruyter	15	50	139	150	156	162	170	173	-	-	-	-
Ooyodo	0	39	163	173	-	-	-	-	-	-	-	-
Katori	22	62	103	114	119	124	132	134	144	149	164	169
Kashima	24	69	88	96	102	106	113	115	124	128	141	146

4-Slot Destroyer/Light Cruiser

Ship	Min ASW	Max ASW
			4 Slots
			T4S/T4S/T4S/T3DCP (44)	T3S/T3S/T3S/T3DCP (38)	T3S/T3S/T3DCP/T2DC (35)
Tashkent	40	73	50	66	75
Yuubari	24	69	71	84	91
Yuubari Kai Ni	49	83	84	84	84
Yuubari Kai Ni Toku	27	70	86	86	88
Gotland	38	62	75	99	112
Giuseppe Garibaldi	25	60	88	105	114
Duca degli Abruzzi	25	59	91	108	117
Ooyodo	0	39	143	158	165
Katori	22	62	85	158	107
Kashima	24	69	62	84	91

Destroyer Escorts

Ship	Min ASW	Max ASW
			2 Slots			1 Slot
			T4S/T4S (24)	T3S/T3S T4S/T3DCP (20)	T3S/T3DCP (18)	T4S (12)	T3S (10)
Shimushu	32	72	10	20	25	40	45
Kunashiri	31	70	13	23	28	44	49
Ishigaki	32	75	10	19	24	37	42
Hachijou	31	72	13	22	27	42	46
Etorofu Matsuwa Tsushima Fukae	35	72	3	14	19	35	41
Sado	36	73	1	11	17	33	38
Mikura Hiburi	40	78	1	1	6	21	27
Daitou	40	77	1	1	6	22	27

Light Carriers

Ship	Min ASW	Max ASW
			931/931/931 (21)	931/931 (14)	931/ (7)
	Taiyou	35	69	30	47	67
Shinyou	36	60	33	62	91
Zuihou K2 B	32	48	75	118	161
Gambier Bay	30	68	45	55	73