Reference

US Navy Dive Tables

The air diving tables from the US Navy Diving Manual, Revision 7 Change A: Tables 9-7, 9-8 and 9-9. Descent rate up to 75 ft/min, ascent rate 30 ft/min.

Depths are in feet of seawater (fsw), as printed in the manual. The small meter values are conversions for reference (1 ft = 0.3048 m).

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No-Decompression Limits (Table 9-7)

Find your depth row, then the first time that is equal to or longer than your bottom time. The letter at the top of that column is your repetitive group.

Depth (fsw)	No-stop limit	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	Z
103 m	Unlimited	57	101	158	245	426	*
154.6 m	Unlimited	36	60	88	121	163	217	297	449	*
206.1 m	Unlimited	26	43	61	82	106	133	165	205	256	330	461	*
257.6 m	1102	20	33	47	62	78	97	117	140	166	198	236	285	354	469	992	1102
309.1 m	371	17	27	38	50	62	76	91	107	125	145	167	193	223	260	307	371
3510.7 m	232	14	23	32	42	52	63	74	87	100	115	131	148	168	190	215	232
4012.2 m	163	12	20	27	36	44	53	63	73	84	95	108	121	135	151	163
4513.7 m	125	11	17	24	31	39	46	55	63	72	82	92	102	114	125
5015.2 m	92	9	15	21	28	34	41	48	56	63	71	80	89	92
5516.8 m	74	8	14	19	25	31	37	43	50	56	63	71	74
6018.3 m	63	7	12	17	22	28	33	39	45	51	57	63
7021.3 m	48	6	10	14	19	23	28	32	37	42	47	48
8024.4 m	39	5	9	12	16	20	24	28	32	36	39
9027.4 m	33	4	7	11	14	17	21	24	28	31	33
10030.5 m	25	4	6	9	12	15	18	21	25
11033.5 m	20	3	6	8	11	14	16	19	20
12036.6 m	15	3	5	7	10	12	15
13039.6 m	12	2	4	6	9	11	12
14042.7 m	10	2	4	6	8	10
15045.7 m	8		3	5	7	8
16048.8 m	7		3	5	6	7
17051.8 m	6			4	6
18054.9 m	6			4	5	6
19057.9 m	5			3	5

* The highest group you can reach at this depth, however long the dive.

Surface Interval Credit (Table 9-8)

Start in the row of your group letter from the last dive. Move right to the cell that contains your surface interval (h:mm). The letter at the top of that column is your new group.

Group at surfacing	Z	O	N	M	L	K	J	I	H	G	F	E	D	C	B	A
A																0:10 2:20*
B															0:10 1:16	1:17 3:36*
C														0:10 0:55	0:56 2:11	2:12 4:31*
D													0:10 0:52	0:53 1:47	1:48 3:03	3:04 5:23*
E												0:10 0:52	0:53 1:44	1:45 2:39	2:40 3:55	3:56 6:15*
F											0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:31	3:32 4:48	4:49 7:08*
G										0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:23	4:24 5:40	5:41 8:00*
H									0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:16	5:17 6:32	6:33 8:52*
I								0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:13	5:14 6:08	6:09 7:24	7:25 9:44*
J							0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:13	5:14 6:06	6:07 7:00	7:01 8:16	8:17 10:36*
K						0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:13	5:14 6:06	6:07 6:58	6:59 7:52	7:53 9:09	9:10 11:29*
L					0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:13	5:14 6:06	6:07 6:58	6:59 7:50	7:51 8:44	8:45 10:01	10:02 12:21*
M				0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:13	5:14 6:06	6:07 6:58	6:59 7:50	7:51 8:42	8:43 9:37	9:38 10:53	10:54 13:13*
N			0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:13	5:14 6:06	6:07 6:58	6:59 7:50	7:51 8:42	8:43 9:34	9:35 10:29	10:30 11:45	11:46 14:05*
O		0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:13	5:14 6:06	6:07 6:58	6:59 7:50	7:51 8:42	8:43 9:34	9:35 10:27	10:28 11:21	11:22 12:37	12:38 14:58*
Z	0:10 0:52	0:53 1:44	1:45 2:37	2:38 3:29	3:30 4:21	4:22 5:13	5:14 6:06	6:07 6:58	6:59 7:50	7:51 8:42	8:43 9:34	9:35 10:27	10:28 11:19	11:20 12:13	12:14 13:30	13:31 15:50*

* After a surface interval longer than the last time in a row, the next dive is not a repetitive dive. Plan it as a first dive.

Residual Nitrogen Time (Table 9-8)

Take the column of your new group and the row of the repetitive dive depth. Add that time to the bottom time of the repetitive dive. The sum is the equivalent single dive time, which you use to read Table 9-7 or 9-9.

Repetitive dive (fsw)	Z	O	N	M	L	K	J	I	H	G	F	E	D	C	B	A
103 m	**	**	**	**	**	**	**	**	**	**	**	427	246	159	101	58
154.6 m	**	**	**	**	**	**	**	**	450	298	218	164	122	89	61	37
206.1 m	**	**	**	**	**	462	331	257	206	166	134	106	83	62	44	27
257.6 m	†	†	470	354	286	237	198	167	141	118	98	79	63	48	34	21
309.1 m	372	308	261	224	194	168	146	126	108	92	77	63	51	39	28	18
3510.7 m	245	216	191	169	149	132	116	101	88	75	64	53	43	33	24	15
4012.2 m	188	169	152	136	122	109	97	85	74	64	55	45	37	29	21	13
4513.7 m	154	140	127	115	104	93	83	73	64	56	48	40	32	25	18	12
5015.2 m	131	120	109	99	90	81	73	65	57	49	42	35	29	23	17	11
5516.8 m	114	105	96	88	80	72	65	58	51	44	38	32	26	20	15	10
6018.3 m	101	93	86	79	72	65	58	52	46	40	35	29	24	19	14	9
7021.3 m	83	77	71	65	59	54	49	44	39	34	29	25	20	16	12	8
8024.4 m	70	65	60	55	51	46	42	38	33	29	25	22	18	14	10	7
9027.4 m	61	57	52	48	44	41	37	33	29	26	22	19	16	12	9	6
10030.5 m	54	50	47	43	40	36	33	30	26	23	20	17	14	11	8	5
11033.5 m	48	45	42	39	36	33	30	27	24	21	18	16	13	10	8	5
12036.6 m	44	41	38	35	32	30	27	24	22	19	17	14	12	9	7	5
13039.6 m	40	37	35	32	30	27	25	22	20	18	15	13	11	9	6	4
14042.7 m	37	34	32	30	27	25	23	21	19	16	14	12	10	8	6	4
15045.7 m	34	32	30	28	26	23	21	19	17	15	13	11	9	8	6	4
16048.8 m	32	30	28	26	24	22	20	18	16	14	13	11	9	7	5	4
17051.8 m	30	28	26	24	22	21	19	17	15	14	12	10	8	7	5	3
18054.9 m	28	26	25	23	21	19	18	16	14	13	11	10	8	6	5	3
19057.9 m	26	25	23	22	20	18	17	15	14	12	11	9	8	6	5	3

** No residual nitrogen time is defined for these groups at 10-20 fsw. The dive has no time limit, and you leave it in the same group (paragraph 9-9.1).
† Read down to the 30 fsw row, use those residual nitrogen times and decompress on the 30 fsw schedule.

Air Decompression Table (Table 9-9)

One table for each depth from 30 to 300 fsw. Open a depth to see its schedules. Each bottom time has two rows: in-water decompression on air, and in-water decompression on air with oxygen at the shallow stops.

Stop columns show stop depth in fsw; the numbers are minutes at that stop. Bold numbers are oxygen stops.
Stop times include the travel time from the previous stop, except the first air stop and the first oxygen stop.
Total ascent time includes the 5-minute air breaks on oxygen: one after every 30 minutes, none when the oxygen time is 35 minutes or less.
A blank group means no repetitive dive deeper than 20 fsw for 18 hours.

30 fsw9.1 mNo-stop limit: 371 min

35 fsw10.7 mNo-stop limit: 232 min

40 fsw12.2 mNo-stop limit: 163 min

45 fsw13.7 mNo-stop limit: 125 min

50 fsw15.2 mNo-stop limit: 92 min

55 fsw16.8 mNo-stop limit: 74 min

60 fsw18.3 mNo-stop limit: 63 min

70 fsw21.3 mNo-stop limit: 48 min

80 fsw24.4 mNo-stop limit: 39 min

90 fsw27.4 mNo-stop limit: 33 min

100 fsw30.5 mNo-stop limit: 25 min

110 fsw33.5 mNo-stop limit: 20 min

120 fsw36.6 mNo-stop limit: 15 min

130 fsw39.6 mNo-stop limit: 12 min

140 fsw42.7 mNo-stop limit: 10 min

150 fsw45.7 mNo-stop limit: 8 min

160 fsw48.8 mNo-stop limit: 7 min

170 fsw51.8 mNo-stop limit: 6 min

180 fsw54.9 mNo-stop limit: 6 min

190 fsw57.9 mNo-stop limit: 5 min

200 fsw61 mExceptional exposure

210 fsw64 mExceptional exposure

220 fsw67.1 mExceptional exposure

250 fsw76.2 mExceptional exposure

300 fsw91.4 mExceptional exposure

How to read the tables

Round your maximum depth up to the next depth in the table, and your bottom time up to the next time.
If the bottom time is within the no-stop limit, read your group letter from Table 9-7. If it is longer, use the schedule for that depth and time in Table 9-9.
For a second dive, find your new group in the surface interval table, then read the residual nitrogen time for the next dive's depth.
Add the residual nitrogen time to the planned bottom time. Plan the repetitive dive with this sum as if it were a single dive.

Terms used in the tables

Bottom time: The time from leaving the surface to leaving the bottom, in minutes. Descent time is part of it.
Repetitive group: A letter from A to Z that tracks the nitrogen left in the body after a dive. It falls as the surface interval gets longer.
Residual nitrogen time: The minutes a repetitive dive is treated as having already spent at its depth because of nitrogen left from the earlier dive.
Air/O₂ decompression: Stops deeper than 30 fsw are on air. The diver then breathes 100% oxygen at the shallow stops (bold in the table), which shortens decompression. It needs an oxygen supply at the stops.
SurDO₂: Surface decompression on oxygen. The diver finishes the in-water stops down to 40 fsw, surfaces and is back under pressure in a chamber within 5 minutes, breathing oxygen at 50 and 40 fsw. The chamber O₂ periods column counts 30-minute oxygen periods.
Exceptional exposure: Dives with a much higher risk of decompression sickness, oxygen toxicity or exposure: every air dive deeper than 190 fsw, more than 90 minutes of in-water decompression, or more than 4 chamber oxygen periods. The Navy uses these schedules for emergencies such as a trapped diver.

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This page is for education and reference. The US Navy tables are written for Navy divers with surface-supplied gear, recompression chambers and trained supervisors. Recreational dives stay within no-decompression limits and 130 ft (40 m). Plan real dives with your training agency's tables and a dive computer.

Source: US Navy Diving Manual, Revision 7 Change A (30 April 2018), Volume 2, Chapter 9, Tables 9-7, 9-8 and 9-9. Change A did not change these tables, so they match Revision 7 (December 2016). The older Revision 6 tables have different limits, for example 60 minutes at 60 fsw instead of 63.