Nemo Wide and US Navy Diving Manual revision 6

[andy100]

Hi,
the new tables published by US navy do set new procedures and time for dives, (deco limit, curve etcc.) In particular the manual do establish the highest stop at 6mt. Our computers (sw. ver.2) do set the last deepstop at 3mt which is consider not a safe procedure by US Navy. Is there a software update planned to take in consideration the new tables or there is a way of modifing setting to limit the last stop to 6mt?
Thanks
Andrea

 

[kgault]

Hi,
the new tables published by US navy do set new procedures and time for dives, (deco limit, curve etcc.) In particular the manual do establish the highest stop at 6mt. Our computers (sw. ver.2) do set the last deepstop at 3mt which is consider not a safe procedure by US Navy. Is there a software update planned to take in consideration the new tables or there is a way of modifing setting to limit the last stop to 6mt?
Thanks
Andrea

The US Navy (NAVSEA) did not choose the 20 fsw last stop for decompression on Air to reduce the risk of decompression sickness - it was chosen for other operational considerations. The estimated risk of decompression sickness is lower for shallower last stops when oxygen is not used as a decompression gas.

There is a Technical Report describing the model used to calculate the decompression tables in Rev 6 available through the Rubicon Foundation website; A second report detailing the changes for Rev 6 including a risk analysis will be available in the near future.

I doubt Mares is considering changing their last stop depth based upon Rev 6 of the Navy Diving Manual.

If you have questions regarding US Navy procedures you can post a question in the NEDU forum (on this site under technical) and the Executive Officer will have the question answered by a technical expert.

Keith

 

[andy100]

The US Navy (NAVSEA) did not choose the 20 fsw last stop for decompression on Air to reduce the risk of decompression sickness - it was chosen for other operational considerations. The estimated risk of decompression sickness is lower for shallower last stops when oxygen is not used as a decompression gas.

There is a Technical Report describing the model used to calculate the decompression tables in Rev 6 available through the Rubicon Foundation website; A second report detailing the changes for Rev 6 including a risk analysis will be available in the near future.

I doubt Mares is considering changing their last stop depth based upon Rev 6 of the Navy Diving Manual.

If you have questions regarding US Navy procedures you can post a question in the NEDU forum (on this site under technical) and the Executive Officer will have the question answered by a technical expert.

Keith

Hi Keith,
thanks. Do you mean that the stop at 20 fsw was not choose to reduce decompression sickness and that we will have to stick to it?. Reading the manual it does not seems so.
For decades the stop has been at 3mt...I do not understand which are the "operative reasons" to make it deeper......
Can you point to me the title of the report on the Rubicon Foundation? It will be extremely useful.
Thanks a lot
Andrea

 

[300bar]

You could start here NEDU Q&A - ScubaBoard

 

[kgault]

Hi Keith,
thanks. Do you mean that the stop at 20 fsw was not choose to reduce decompression sickness and that we will have to stick to it?. Reading the manual it does not seems so.
For decades the stop has been at 3mt...I do not understand which are the "operative reasons" to make it deeper......
Can you point to me the title of the report on the Rubicon Foundation? It will be extremely useful.
Thanks a lot
Andrea

The change in last stop depth was not made to reduce the risk of DCS for in-water air decompressions. While choosing the last stop depth for Rev 6, the risks were lower when the air decompression had a last stop of 10 fsw rather than 20 fsw. One of the operational reasons given for the choice of a 20 fsw last stop for the air decompression tables was to reduce injuries when decompressing on a stage in heavy seas.

Two good references:
Suitability of VVAL-18 for Air diving: Rubicon Research Repository: Item 123456789/4586

Development of the Thalmann Algorithm (VVAL-18 parameters): Rubicon Research Repository: Item 123456789/5490

Note: Rev 6 uses VVAL-18M not VVAL-18. The document of these changes is in the forthcoming report. I made a post in the NEDU forum on some of the changes.

There was a presentation by Ed Flynn at the 2009 Undersea Hyperbaric Medical Society Scientific Meeting that discussed the Rev 6 changes in more detail - I cannot find the presentation at present - Gene Hobbs will know how to get ahold of it.

Keith

 

[andy100]

Hi Keith thanks for your reply. Ed Flynn presentation will be extremely useful to understand the detail of rev. 6 changes. Summarising the 10fsw stop is still the safest and 20fsw was choosen for operative reasons? Is that right? I think that this should be highlighted as it seems that diving association are considering to update their education programs to adopt the new standards set in rev.6.
thanks
Andrea

 

[Zak OHara]

I am not aware of Mares making any changes to current algorithm / dive profile used in all Mares computers.

Good question though..

 

[andy100]

I am not aware of Mares making any changes to current algorithm / dive profile used in all Mares computers.

Good question though..

Thanks for your clarification. Hope to get access to flynn presentation to understand the logic behind the changes in table rev.6.
Andrea