Hypothetical Accident Help

I am posting in this thread because I don't know where else to post, so Mod if you need to move me no problem. I am a writer and am working on a novel. I decided for this one to mix my love of diving with my love of writing. But I need some help.

In the story line, a person is trying to stop work being done on a wreck by messing with their on board air compressor, resulting in bad air for a group of divers. For those of you with much more experience than myself:

1. What could someone do to an air compressor that would allow it to still run, but would result in contaminated air. (I don't need enough details so that someone could actually do this, but enough so that my writing isn't technically incorrect)

2. What would the contaminated air taste like? (I know we're trained that if air tastes "funny" to not use it. But can anyone describe "funny?"

3. How soon would a diver feel physical effects?

4. How severe would the physical effects be?

5. At what range to shore and what severity does the Coast Guard get involved in something like this?

Thank you for your help!!

interesting questions. i'm in no way an expert but spent last night in a holiday inn express.

i'd think all you'd need to do to mess up the air would be to spray pretty much anything into the intake while the compressor's running. ok, maybe not water, but bleach or hair spray or canned car exhaust would all work. i'd think the contamination might not taste like anything (if it's carbon monoxide, for instance) or might taste like bleach or hair spray or canned car exhaust. how soon and how severe would depend on what it was and in what concentration, and i think the coast guard can be called by anyone.

have fun with your novel!

Is this really for a novel?

AndyM:

1. What could someone do to an air compressor that would allow it to still run, but would result in contaminated air. (I don't need enough details so that someone could actually do this, but enough so that my writing isn't technically incorrect)

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Do you mean intentionally or unintentionally? If it's intentional, the sky's the limit. You could put anything in the air and there are lots of odorless, colourless agents that wouldn't be good for you while you're diving. If it's unintentional your options are more limited.

2. What would the contaminated air taste like? (I know we're trained that if air tastes "funny" to not use it. But can anyone describe "funny?"

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If the compressor isn't working and/or if the filter is extremely dirty then oil gets into the air. The air smells and tastes oily. At depth this will give you a headache and possibly make you feel light headed (don't ask me why I know this ). The wrinkle for your story is that the smell of the air is so strong that the divers in your story will either have to be clueless trusting types to go ahead and dive with it or there must be some other mitigating circumstance that forces them in the water with air they know is contaminated.

Another kind of contamination could be caused by the air intake of the compressor somehow sucking in diesel fumes from the boat's exhaust. I don't know what that smells or tastes like but I would imagine it smells like diesel exhaust. The effects would depend on how bad the contimination is but it could include lips and the base of finger nails turning bright read, dizziness, fainting, drowning etc etc. Once again, the wrinkle for your story is going to be that it's easy to smell it.

3. How soon would a diver feel physical effects?

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I guess it would depend on depth and the amount of contamination but after 15 minutes you could put them in serious trouble.

4. How severe would the physical effects be?

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It would depend on how contaminated the air was but you'll be able to find some stories around. Mark Eylatt describes the effects of contamination from cleaning agents in his book ... title escapes me but something like "gladiator". The rescue manual from PADI will give you a list of signs and symptoms you can build on. Probably starting a thread here in the basic section asking for people to tell you their stories will get you something. I think I'll move this thread to the basic section anyway because it will get more attention over there and this doesn't really belong in the accidents section.

5. At what range to shore and what severity does the Coast Guard get involved in something like this?

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This is regionally dependent. Your best bet might be to contact the coast-guard in the area where your book will be set to ask them for a description.

R..

All of this is just idle speculation! Those divers' families might come here and see these posts! You are risking that dive ops' business! Nobody here knows what really happened down there, so you should all stop posting until the official report from the authorities and coroner comes out!

AndyM:

Hypothetical Accident Help

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Hypothetical? Oh. Nevermind.

Diver0001:

If it's intentional, the sky's the limit. You could put anything in the air and there are lots of odorless, colourless agents that wouldn't be good for you while you're diving.

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Yes, but if the malefactor uses sarin gas it's highly suspicious, whereas carbon monoxide doesn't raise an eyebrow. Have him burn some charcoal briquets near the intake valve. Low tech, but effective.

At deep depths (say 180' or so) using large compressor that has a supplemental gas feeds for providing different gas mixtures, you could disconnect a tank containing He2 and connect a 3HP sized O2 tank, crank it open, and give them an O2 hit. If using full face-mask regulators, they'd be alive but unconscious after a seizure. It could be fatal after some length of time (ask a barometric medicine doc how long) but largely they'd more or less immediately be unconscious.

Problematically, that kind of long bottom time work these days is most likely using re-breathers.

vladimir:

Yes, but if the malefactor uses sarin gas it's highly suspicious, whereas carbon monoxide doesn't raise an eyebrow. Have him burn some charcoal briquets near the intake valve. Low tech, but effective.

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Yeah, that would work for a novel. They have a barbecue on deck while the tanks are filling and the intake sucks up the fumes from the briquettes...

R..

The problem you'd have (or your character would have) is that it would only slow down operations for a single dive, because anything that effected the breathing gas would be noticed on the first dive with that bad gas, the compressor would be the obvious suspect, would be addressed, and dive ops would continue on.

Unless folks died from CO poisoning...

First you would have to get past the compressor operator. He might be the picky type who would take your activities the wrong way, since his reputation, freedom and bank account depends on keeping the divers alive by supplying them with clean air, and throw you overboard, beat you to a pulp or have you chained up below. It would probably be simpler to screw up the engines with some sugar or anti-freeze which wouldn't have a tendency to main any of your fellow divers and piss people off.