Navy Dive Tables

[Sam Miller III]

Sam

Do you have the 1952 manual as well? If so, was the ascent rate in the 1952 manual also 25'/minute? Based on this summary Aqualung-style SCUBA was introduced in Part 3 of the 1959 (1958?) manual.

CLASSIC DIVING BOOKS - US NAVY DIVING MANUAL

I have been curious for years.....

QUOTE]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Hombre, I have all the USN diving manuals

I suspect the one you are interested in is the supplement Part 111 which covers "self contained diving" aka SCUBA.
(8-1/2 X 11 cardboard bound 72 pages)

NAVSHIPS 250-538
US Navy Diving manual
Navy department
Washington, D.C.


Part 3
SELF CONTAINED DIVING

No apparent mention of the rate of assent

On page 3.4.7 there is a reproduction of the "duration in minutes" chart which was previously printed in numerous dive training manuals; the Hahn report, Rene Bussoz, Cousteau/Gagnon, ER Cross and LA County Underwater Instructions association's "Underwater Recreation."

I suspect if I reviewed NAVSHIPS 250-538 I will locate a recommended rate of assent. I am currently over loaded with a contract but I will when the pressure less and my time allows.

good luck
SDM

 

[Basking Ridge Diver]

I think I found what you were looking for...

A copy of the Navy tables - NDL with Decompression.
http://www.matzenauer.org/diving/Navy_air_tables.pdf

How to read the tables and a few example questions.
http://www.google.com/url?sa=t&rct=...jEAW9H0s1MQtdiw&bvm=bv.80642063,d.aWw&cad=rja

 

[Michael Guerrero]

All these old farts kind of hijacked your thread.

I have my training from SSI and understand that each brand of training is a little different, but now I look at the cards and see some differences on how to work through them. Also, the decompression table on the back is greek to me.

The tables will be setup a little differently, so you will work through them slightly differently, but the overall process is generally the same. Find your depth, find your bottom time, ensure it does not exceed the NDL and you're good. If you are going to do a repetitive dive, then find your surface interval, select the right residual nitrogen group, find your new NDL based on depth, and keep your dive to less than that.

As far as the deco table goes, don't worry about that until you get the training. It basically outlines how long of a stop you need to make at each depth heading toward the surface. I bought the IANTD ones from DGX with the accelerated deco, and can walk you through in more detail if you want to PM me.

I would like to get an idea of where the tables originated, and a basic idea of how the decompression table is set up.

As was stated, the tables were empirically derived, while being informed by theory and accepting a certain percentage of DCS (I think it's about 2%).

I'm just curious in the differences between the SSI tables and the US Navy tables

The SSI tables are likely more conservative than the Navy tables.

---------- Post added December 2nd, 2014 at 08:22 PM ----------

They work really well, for a perfect specimen of a 20 year old male with 2% body fat.

Gross exaggeration.

 

[boulderjohn]

The SSI tables are likely more conservative than the Navy tables.

I may be mistaken, but I thought they were the same. I do not believe SSI did any independent research.

 

[Akimbo]

Those are pretty new editions. We are looking for pre-1959 editions of the manual to figure out when the rates changed from 25or 30'/minute to 60'/Minute. I know they are 30'/minute now.

 

[Michael Guerrero]

I may be mistaken, but I thought they were the same. I do not believe SSI did any independent research.

They are not. SSI NDL for 130ft is 5min, Navy is 10min (table 9-7). They are "based" on the Navy tables, but they are more conservative. That is standard across all agencies I'm familiar with.

 

[boulderjohn]

They are not. SSI NDL for 130ft is 5min, Navy is 10min (table 9-7). They are "based" on the Navy tables, but they are more conservative. That is standard across all agencies I'm familiar with.

The PADI tables are more conservative on the first dive only. When they were made, the Navy tables based surface intervals on the 120 minute compartment. PADI's reserach indicated that the 40 minute compartment was appropriate for the kind of diving that recreational divers did. They then used the 60 minute compartment for their tables in order to be conservative, but not as conservative as the navy tables. This gives much shorter surface intervals.

 

[Michael Guerrero]

Ah. I am under the impression the Navy guys typically only did/do one dive a day for normal ops. Is that correct? Less ongassing due to shorter NDL should accommodate shorter SIs right?

 

[boulderjohn]

Ah. I am under the impression the Navy guys typically only did/do one dive a day for normal ops. Is that correct? Less ongassing due to shorter NDL should accommodate shorter SIs right?

Yes, shorter NDLs will call for shorter surface intervals, but the difference in the compartment chosen to control the surface intervals had a much bigger effect. A compartment is considered to be washed out after 6 halftimes. If you went to the max on the Navy tables with the 120 minute compartment controlling it, you would wash out after a 12 hour surface interval. If you did the same thing with the PADI tables, you would wash out after 6 hours.

 

[Akimbo]

Ah. I am under the impression the Navy guys typically only did/do one dive a day for normal ops. Is that correct?...

Navy and civilian commercial divers rarely do more than two dives/day unless it is pretty shallow or there are long intervals between underwater tasks. Two dives is common in ship's husbandry work which is not much deeper than the keel, but can burn divers up through exertion and cold. It takes enough people to run a surface-supplied diving operation that you can usually keep it to one or two jumps/day just getting through the rotation.