73 mts direct to deco chamber

[emoreira]

I was watching in trueTV channel a show about underwater rescue. The show was about a group that was extracting an oil platform leg from the seabed in the gulf of Mexico. The commercial diver was at a depth of 73 meters (240 ftsw). He was installing some explosives. After the explosives were laid down, he had to hurry to the surface. No deco stop. There was no mention of the gas mixture used. As soon as he arrived to the deck of the barge, he was introduced to the deco chamber.
I've heard this before. Is this the normal procedure ?

 

[Akimbo]

Sur-D- O2 (Surface Decompression using Oxygen) is the norm for most surface dives requiring decompression. It has been used for at least 70 years. Water stops are frequently required. There are a lot of tables around, both published and proprietary. All the tables I have seen allow 5 minutes from the time the diver leaves the last water stop, or passes a specified depth, and is back to the deep stop in the chamber — usually 60' on pure O2.

 

[Wookie]

Even on deeper dives when using a bell, the diver is brought to the surface in the bell pressurized to depth, blown down to surface pressure, given a ciigarette while the tender undresses him, and jumps into the chamber for his deco.

 

[Nitro91]

why dont they do in water deco stops?

or is it easier or more efficient to just jump straight into a chamber lol.

 

[AaronRiot]

I am confused... so these divers will knowingly run the risk of/get bent because there is a chamber at the surface to "unbend" them? That seems pretty dangerous? Especially in a non-emergency situation where they could deco on the way up. Maybe I'm missing something, I am new...

 

[Nitro91]

I Dunno LOL ¯\(°_o)/¯

 

[Tigerman]

The simplified answer is "No, they just decompress in the chamber instead of in the water"..

 

[t4e]

this is from an article i read recently

However, non submersible decompression chambers are more common.The diver surfaces and immediately enters the decompression chamber to complete the time they would have spent, doing decompression stops underwater. This reduces the risks for divers diving in cold waters or in risky underwater conditions. Not to forget, this method of decompressing is mostly used in the case of commercial diving, which involves divers working for hours underwater at depths far beyond traditional recreational diving. Because of which they also spend hours (sometimes as long as 18 hours) for the decompression process.

 

[Wookie]

To expand on Tigerman's answer, yes, it is more dangerous to do your stops in the water. You are a foreign visitor in the water and you can't breath it. You are colder in the water, even in a heated suit, so deco takes longer and isn't as efficient. There are large toothy things in the water, and the surface supplied umbilical is prone to getting damaged while hanging over the side of the ship.

If you put a diver in a chamber, he is tended, you can get him medical attention, he can be fed, (some of these guys take days to bring to the surface, BTW), he is warm, he can go to the potty, he can do all of the things you can do on a daily basis except he is confined to a small room.

A saturation diver is not blown down like you saw on TV. Saturation ships are very specialized and the saturation bell can mate to the chamber. The divers are brought to the surface in saturation and transferred to the chamber, then slowly brought to the surface. They are never dumped and blown back down.

 

[DivingOtter]

why dont they do in water deco stops?

or is it easier or more efficient to just jump straight into a chamber lol.

Controlled environment and safety. Some of the dive tables call for hours upon hours of decompression. What is better? Doing it where the diver can be warm, comfortable and monitored? or at depth, cold, and only having communications and video?

---------- Post added April 22nd, 2012 at 10:43 AM ----------

No.. Decompression charts are a very complex system of numbers and time down to the foot and to the second. It is a carefully monitored procedure. without going into the mixed gas side of it, heres a simple breakdown. At 40 feet the diver will do an in water stop. From the second that stop is complete he has 5 minutes to reach depth in the chamber. One minute from ascent from stop, 03::30 to get stripped out of all gear, and 30 seconds to get down to depth. Its like a controlled chaos. Figure 5 hours ( just going off memory ) doing in water, vs 5 hours of controlled, monitored, warm and cozy.