Emergency Surface from 250 FT and reascent procedures

[DCBC]

...Unfortunately, the type of DCS symptoms you are likely to experience on the Doria are not likely to be reasonable to treat in the water. Nor are the sea-state conditions you are likely to encounter for more than a few hours at a time. Just doing normal in-water decompression stops hanging off a moored vessel can be very challenging.

Akimbo, unless the sea state, currents and water temperature were a whole lot different than I experienced at this site, there's no way that I would even consider in-water treatment of a DCS injury. Like you correctly pointed-out, diving this wreck is dangerous and ideally it should be undertaken with proper support. In any event, the diver must accept the risks involved. I fear however, that many that attempt this dive don't. It sure can be a high price to pay to find out.

 

[Akimbo]

... Like you correctly pointed-out, diving this wreck is dangerous and ideally it should be undertaken with proper support. In any event, the diver must accept the risks involved. I fear however, that many that attempt this dive don't. It sure can be a high price to pay to find out.

We won't have to worry about it much longer; the Doria will be a pile of scrap plate on the bottom soon. Scapa Flow is looking better all the time. Even though those ships have been underwater 37 years longer, they are all-steel and heavily compartmented warships. Even Truk's wrecks are mostly merchantmen and are going fast.

Please bear with me; I am experiencing another wreck-addiction relapse.

 

[Thalassamania]

Yup a NE dive boat with a chamber would be nice, make it a habitation chamber with a TUP connector and a PTC? Maybe a Lockout sub? A half dozen Hardsuits? Etc.?

 

[Akimbo]

I didn't want to hijack this thread but it helped inspire this one:

http://www.scubaboard.com/forums/ad...ns/438153-managing-oxygen-toxicity-risks.html

Yup a NE dive boat with a chamber would be nice, make it a habitation chamber with a TUP connector and a PTC? Maybe a Lockout sub? A half dozen Hardsuits? Etc.?

I think I can find one, sort of pricey though.

I really was bummed when that company's deal on the boat fell apart, they already had the chamber. Their Web site is dead now.

 

[ianr33]

Was the guy mentioned in the OP suffering DCS symptoms? Or did he just descend after a short time on the surface to do omitted decompression?

2 very different situations.

 

[Jerrod]

Was the guy mentioned in the OP suffering DCS symptoms? Or did he just descend after a short time on the surface to do omitted decompression?

2 very different situations.

The book does not say. It just says the guy had a regulator problem and began to ascend the line. It makes mention of the fact that he passed multiple people on the way up and he was holding his breath and felt a tingling in his throat. Once he surface the owner of the boat, the seeker, "yelled at him, ran some software, and sent him to decompress for four hours." There was no mention of DCS.

 

[DCBC]

Yup a NE dive boat with a chamber would be nice, make it a habitation chamber with a TUP connector and a PTC? Maybe a Lockout sub? A half dozen Hardsuits? Etc.?

In the event that the Global Orion isn't available, perhaps the USN might loan us the "Grapple" for a few days...

 

[Jerrod]

Tech divers don’t like hearing this, but dives like this without a chamber on site is foolish at best, even if you are surface supplied. Regardless of expertise or preparation, you can easily get seriously bent even when the dive is executed flawlessly. We all take calculated risks so diving the Doria without a treatment chamber and people onboard that can operate it is accepting that you will die or be crippled if you needed one.

Yes, I have been there and yes, there was a double-lock onboard. Oh, and yes we used it. Everyone came home exhausted but fine.

After reading the Last Dive about the U-who, I have to say that what you are saying seems to be correct. After this last book (last dive), I didn't fully grasp how bad DCS is. But what the Rouses died of, it doesn't even matter if a chamber was on board. The book and an article I read said only a 400 ft deco would have worked (among other things).

Why don't we use com gear? The last dive speaks over and over about if everyone simply had com gear most accidents wouldn't occur. I am sure that's another thread though.

 

[waterpirate]

That is the the risk we take. Stress and a poor gas choice (imho) all contributed to that incident, as well as being mission driven to the point of obsession. No matter how safe we make cars, they still bend and hurt people when we run into each other.
Eric

 

[Akimbo]

… But what the Rouses died of, it doesn't even matter if a chamber was on board. The book and an article I read said only a 400 ft deco would have worked (among other things)...

That is inconsistent with my experiance. U-869 at 230' is in about the same depth as the Doria at 240'. You have to remember the ratio of bubble compression. That is why treating hits from 200'+ dives are often in a chamber at 60' -- mostly US Navy Tables 5 & 6, but also others.

There are two major issues involved, diluent gas bubble compression (often immediate relief) and removal from the blood stream. Compressing the bubble about a third (60') will often restore most blood flow and high PPO2 (pure oxygen) removes it from the blood very rapidly (2.82 ATA). It is very unusual that chamber DCS treatments for military or commercial HeO2 dives below 300' treat deeper than 165'.

There are standard Navy treatment tables for 165' and deeper, but it usually means much lower treatment PPO2 (air). Recompressing to 165' would drive the vast majority of diluent gas back into solution from a 230' dive. All the chambers I have worked with were rated to 300' pressure-equivalent, though rarely had the treatment gasses required below 225'.

The Rouses may well have ended up on a 165' or even 225' table, but 400' would not have made any difference. Granted, there is a lot we don't know about explosive decompression outside of animal studies (thankfully), but rapid recompression would have improved their odds of survival by many many times.

Why don't we use com gear? The last dive speaks over and over about if everyone simply had com gear most accidents wouldn't occur. ...

Lots of reasons. Wireless comms required for Scuba were almost unavailable then and are only marginally reliable now. It also requires a FFM; which seriously complicates gas changes, use of backup regulators, and the added dead air space increases CO2 build-up. Surface supplied divers don't face these problems. Communications are hard-wired, they can use free-flow to clear CO2, and gas changes are managed for them on the surface.