Hey....... Lighten up Francis! We all know that when a DM or a boat OP announces that No Deco diving is permitted.......it implies what it generally means. The DM knows.......The operation knows....... and the divers know.
But........the simple FACT is that anyone who believes that ANY dive on compressed gas does not in fact involve decompression is 100% wrong.
Let's just simplify this. Are you saying that a dive to 60 ft for 50 minutes does not have any issues related to decompression? It's a simple answer. Yes or No.
The answer is "No." There is almost no hazard of bubbles forming as the pressure is released under normal ascent procedures. You are ignoring the time factor for dissolving nitrogen into the diver's tissues and blood. All you see is the physics of lessening pressure. But decompression is a process of releasing dissolved nitrogen from the body.
By the way, there is a reason that Cousteau's Conshelf II project had the Starfish House at just under 33 feet (10 meters) underwater. They did not have to worry about saturating their divers so that they had to decompress. Their Deep Cabin, however, was at 90 feet, and they did have to worry about those two divers, and explained that in the film,
World Without Sun.
Similarly, I dive in rivers a lot. The hole I dive in is 22 feet deep. I can used my twin doubles and stay underwater for extended times (an hour or more), without having to worry about decompression. Yes, I experience a lessening of pressure as I surface. That doesn't represent a "decompression," as there is no hazard from nitrogen dissolved in my tissues at that depth.
SeaRat
DSC00286 by
John Ratliff, on Flickr
Here I'm diving with Sid Macken in Big Cliff Reservoir, and about 30 feet. We made two dives without needing to worry about decompression.
0617ABC6-1BD6-46B2-A933-AF654A2C8DD2 by
John Ratliff, on Flickr
This is one of the Cousteau Deep Cabin divers, who dived to in excess of 300 feet without worrying about decompression as their "home" was at 90 feet. But when ascending to the Starfish House, at 33 feet, they did have such worries.
The Black Masks have held out in the Deep Cabin for the period planned. The time has come to recover Kientzy and Portelatine, who have lived in 3 1/2 atmospheres of pressure for 168 hours. The TV monitor in the cabin transmits to Starfish House Portelatine's preparations for departure from the sweat-box. he and Kientzy don gas masks and breathe equal parts of oxygen and nitrogen for three-and-a-half hours. This reduces the saturated helium in their tissues belowe the danger line...
...1500 housr: 'Here they come!' The Black Masks leave the Deep Cabin and ascend the reef. To be doubly sure of no ill after-effects, the deep men stop at minus fifty feet for twenty minutes of stage decompression. They continue up for ten feet more and holt for thirty minutes. As they cross the yard of Starfish House, the Black Masks are astonished to see Cousteau's wife, Simone, standing in the window. Three days before, feeling utterly tired and half-ill in the heat aboard calypso, she decided to come down for a rest. The Oceanauts moved out of one sleeping bay and she stayed in the Conshelf Station. Her impulse has made Mme Cousteau the first feminine Oceanaut.
Cousteau, Jacques-Yves, World Without Sun, Edited by James Dugan, Harper & Row, Publishers, New York, copyright 1964' Library of Congress Catalog Card Number: 65-14690, pages 191-192.
Here is a Cousteau movie about their Conshelf projects:
