(Pseudo) Military diving

Not sure quite where to post this, but it fits well enough in here.

My other Fratello are a multi-purpose fratello, which, in the situation they’re in, is bureaucrat speak for “here’s a mission, here’s some funds: now go away and don’t bother us until it’s done”. They do wetwork and breaking/entering, with a secondary role as an intelligence fratello.

They operate with as little support and contact with the agency as possible (I think there’s a little more background in the Distress Signal thread if people want more details).

With the exception of firearms, all of their kit is civilian issue, usually acquired by them personally.

I’ve got them infiltrating a property from the water, which involves them getting relatively close using a dive-boat as cover, then infiltrating the property rather than swimming around off-shore as they’re supposed to.

I know nothing about diving (save some very basic research). I know that some of you, however know an awful lot about the subject. So…

1/ What’s the process for getting kitted out and into the water? What’s the reverse process?

2/ When in the water, what are the general rules of thumb to follow? E.g. Aim to have a reserve of 20% of your air remaining when the dive is over in case of emergencies. Rules on decompression stops etc.

3/ What are the other key things you think I need to know about?

4/ Any recommendations for websites or non-fiction books on the subject (by non-fiction books, I’m thinking more about usefully detailed memoirs than technical – I’ve grabbed a US Navy field manual from the web, but it’s light on personal anecdotes and ‘real-life’ situations and detail)?

Thank you in advance

Fett d’Facto

"Professor Voodoo, please click the White Courtesy Reply Button. Professor Voodoo, please click the White Courtesy Reply Button.""

Well, it's difficult to condense years of training into a forum post, so I'll just just address your questions directly...feel free to ask more.

1/ What’s the process for getting kitted out and into the water? What’s the reverse process?
It depends on what gear you're using, but for SCUBA you typically set up & inspect your gear first, then get dressed in while seated on a bench.  Dive partners should inspect each other once fully dressed in.
When undressing you're usually tired...sometimes climbing the ladder back onto the boat is the most difficult and dangerous part of the dive. Getting undressed usually consists of tossing your stuff off with whatever strength you have left.  Putting it all away neatly can wait until you've had some rest & water. 
For surface supplied diving (hard hat diving with a surface tether) you get dressed in while standing, then the tender inspects you. 
A surface supplied diver typically has to rush into the decompression chamber.  You only have 4 minutes from your last in-water deco stop to re-compression in the chamber (3 minutes if breathing a helium-oxygen mix) so it's a mad scramble to get you undressed (helped by the tenders) then a naked sprint to the chamber.  The tenders pick up and attend to your gear. 

2/ When in the water, what are the general rules of thumb to follow? E.g. Aim to have a reserve of 20% of your air remaining when the dive is over in case of emergencies. Rules on decompression stops etc.
For tech diving we go by the rule of thirds.
1/3 of your breathing gas to get to your objective.
1/3 of your gas to come back.
The final 1/3 is kept in reserve for unexpected circumstances.
Tech divers don't call what's in their cylinder "air" unless it actually is 79% nitrogen, 21% oxygen.  We frequently use a different breathing mix to suit the depth & circumstances...i.e. NitrOx, HeliOx or TriMix.

As for decompression stops; there are 500 page volumes of tables for time/depth/breathing mix.  You plan that stuff ahead of time.

3/ What are the other key things you think I need to know about?
I could literally talk for 8 hours straight about this.  Better to just ask specific questions as they come up.

4/ Any recommendations for websites or non-fiction books on the subject 
Look for Garry Gentile's stuff...I recommend Deep, Dark & Dangerous.  It's specifically about civilian diving on the Andrea Doria wreck, but it's informative and entertaining stuff.

I'm just scratching the surface here, so keep tossing questions at me and I'll try to answer them in a timely fashion.

Kiskaloo wrote:Professor Voodoo, please click the White Courtesy Reply Button. Professor Voodoo, please click the White Courtesy Reply Button."

Basically, though I think someone else dives from memory. Elfen?


[quote=Professor Voodoo[/quote]It depends on what gear you're using, but for SCUBA you typically set up & inspect your gear first, then get dressed in while seated on a bench.[/quote]

Dressed in meaning putting on the equipment (weights belt, dive knife, computer etc.) on over a wet/dry suit?

On the topic of wet/dry suits, would you wear a swimming costume under them or not?

Why does a surface-supplied diver typically have to rush to a decompression chamber whereas a non surface-supplied one doesn't? Is this just because they're usually down deeper for longer, or are there other factors in play?

Professor Voodoo wrote:For tech diving we go by the rule of thirds

If you're, for example, wielding a pipe as your objective, presumably that wielding time would come out of the first third?

Professor Voodoo wrote:3/ What are the other key things you think I need to know about?
I could literally talk for 8 hours straight about this.  Better to just ask specific questions as they come up.

I'll bet. I was very aware when typing this that I was asking the equivalent of "explain physics to me". I almost didn't post on the grounds that the subject was just too huge and my questions too general.

The cyborg would be being taught from scratch by her handler, so I suppose that what would probably be most useful for me currently is the level of skill/accessibility of various bits of kit. Specifically, what's the general progression curve from non-diver to technical diver and at what point are there age/qualification requirements? I know you have to be 10 to do the PADI open water course, for example.

What would be the bare minimum capability to infiltrate somewhere by water undetected, if it's just a straight swim in without anti-frogmen measures? I assume it'd be ability to navigate underwater and swim deep enough that the bubbles don't reach the surface (though would using a rebreather remove that particular problem)?



What do they the certification cards detail? Gas mixes you can use and depths you can dive to?

Lastly, if I just turned-up to a dive centre, totally unqualified, what sort of dive (I'm thinking mainly SCUBA here and in terms of depth/equipment) would I be permitted to go on, assuming I was medically fit and supervised while diving?


What I might do is just write something and make a note of everything I can't source/have no idea how it works. I know so little I don't even know what I don't know at this stage.
 

\"Professor Voodoo wrote:Well, it's difficult to condense years of training into a forum post, so I'll just just address your questions directly...feel free to ask more.

Yeah: I tried to narrow the focus a bit, but at this point I don't really have enough specifics or knowledge to really give you something to chew on. I may well keep tossing questions at you. Thanks.

If you're going to borrow from Voodoo's universe as well as pick his brain, be advised that there is a hard depth limit for normally-conditioned cyborgs of about ten meters.

I thought the Voodoo Limit was more around the 30m range, I think that's what I've been working to...

...I could be wrong of course, it has been known to happen before.

if you are going to try and be stealthy wouldn't you use a rebreather to reduce the bubbles ?

For the actual infiltration it might be... though for actually acquiring (from memory this is another pair at the far/non-existent end of the logistics chain?)/explaining why tourists have rebreathers (presuming that's the cover story) might be a bit more difficult.

As an side, for another possible if left-field info source, try the manga Amanchu! which is by the same lady who did Aria and is about, well, SCUBA diving of the civilian variety.

Alfisti wrote:For the actual infiltration it might be... though for actually acquiring (from memory this is another pair at the far/non-existent end of the logistics chain?)/explaining why tourists have rebreathers (presuming that's the cover story) might be a bit more difficult.

As an side, for another possible if left-field info source, try the manga Amanchu! which is by the same lady who did Aria and is about, well, SCUBA diving of the civilian variety.

They aren't that rare, I seem to remember that cave divers use them fairly often as they tend to be more compact than regular SCUBA gear

Alfisti wrote:...actually acquiring (from memory this is another pair at the far/non-existent end of the logistics chain?)/explaining why tourists have rebreathers (presuming that's the cover story) might be a bit more difficult.

They are indeed at the non-existent end of the logistics chain. They might be able to arrange a la carte items, but they wouldn't run the risk/burn the goodwill on something they can just buy with relatively untraceable and uncompromising cash.

Awinnell wrote:They aren't that rare, I seem to remember that cave divers use them fairly often as they tend to be more compact than regular SCUBA gear

Rebreathers are something I'm aware of, but I'm not entirely sure who forgettable tourists using rebreathers (especially one who's 9) would be. You can rent them, but (feel free to chime in Voodoo) it seems like the sort of thing that would be potentially memorable: a father-daughter pair (and it's a daughter young enough not to be able to do her open-water cert) wanting relatively advanced kit, rather than a cheap option to play with.

Sorry to be absent for a few days...so much for "timely responses."

Vett wrote:Dressed in meaning putting on the equipment (weights belt, dive knife, computer etc.) on over a wet/dry suit?

Yes.  The computer is sometimes attached to the regulators via a high-pressure hose (other models are worn on the wrist).  Weight belts are popular, but for military diving it's more likely that the weights would be integrated into the diver's back-plate or in special pockets in the buoyancy compensator vest.

On the topic of wet/dry suits, would you wear a swimming costume under them or not?

Yes, most people do wear some sort of swimsuit under a wetsuit...although 3 busloads of Florida schoolchildren did get to see me completely naked while changing in a parking lot on a day when I wasn't wearing any Lycra shorts.

Since dry suits are usually utilized in colder water the diver is more likely to wear thermal underwear under his/her suit.

Why does a surface-supplied diver typically have to rush to a decompression chamber whereas a non surface-supplied one doesn't? Is this just because they're usually down deeper for longer, or are there other factors in play?

 A non-surface supplied diver (SCUBA) typically doesn't have a decompression chamber available so they plan their dives within "no decompression" limits or do in-water deco stops.

Surface supplied diving is usually used on commercial projects, for industrial diving.  It's not cost-effective to pull divers out after short no deco dives...nor is it cost effective to wait for them to finish long in-water decompression stops.  Better (plus safer & more comfortable) to pull them out and stick them in the chamber so you can get the next diver in to continue the work.

If you're, for example, wielding a pipe as your objective, presumably that wielding time would come out of the first third?

I assume you mean welding.  All welding would be done with surface supplied breathing gear...so you can maintain communication with the surface in case of an accident.  I'm sure somebody has done it, but it would take a serious wacko to do underwater welding on SCUBA.

That rule of thirds is more relevant to caving or shipwreck penetration.  Let's say you start a dive with 3000psi in your bottles...you turn around and head home at 2000psi and keep that last 1000psi in reserve.

 what's the general progression curve from non-diver to technical diver and at what point are there age/qualification requirements? I know you have to be 10 to do the PADI open water course, for example.

A Junior Diver certification allows a kid to dive with certified adult supervision...I think there's a 15 meter depth restriction, but it's not as if there's SCUBA police down there checking.

For adults (and kids stepping up to an adult certification) the progression is;
Open Water → Advanced Open Water → Specialty Certifications → Master Diver
The specialty certifications can include special gasses (Nitrox, HeliOx & TriMix), restricted access environments (shipwreck penetration, caves), or dive master (which allows you to lead tour groups).  These are not essential steps to becoming a Master Diver...I know some Master Diver's who have never been inside a cave and never will.  

For the purposes of your story I think you can be a little flexible with certifications.  Who's seriously going to check the cards on a clandestine Italian government anti-terrorist organization? 

What would be the bare minimum capability to infiltrate somewhere by water undetected, if it's just a straight swim in without anti-frogmen measures? I assume it'd be ability to navigate underwater and swim deep enough that the bubbles don't reach the surface (though would using a rebreather remove that particular problem)?

Simplest way to do that; oxygen rebreather and a compass.

There are two kinds of closed circuit rebreathers, and they're very different:
Oxygen Rebreathers are lightweight, simple and inexpensive.  Most don't even use a dive computer.  They're primarily for military infiltration...I've never seen one used by civilians or commercial industry.  The reason is, they're limited to about 15 feet of depth.  You're breathing 100% oxygen, which becomes more toxic the deeper you go.  By 18 feet it can kill you.
Mixed Gas Rebreathers are big, complicated and expensive...but you can go deep and stay there longer.  The diver can constantly adjust his or her breathing mix on one of these to suit the depth (leaning out the oxygen percentage the deeper you go).  These are used for both military diving and high-end technical civilian diving.

What do they the certification cards detail? Gas mixes you can use and depths you can dive to?

Every certifying agency is different.  I think PADI carts do have a depth limit printed on them.  My NAUI Advanced Open Water card doesn't have any depth limit printed on it, but it's implied that you'll stay within no-decompression limits unless you have a higher cert.
My higher cert, my IANTD Advanced Nitrox card does have a 140ft depth limit printed on it.

Again, there's nobody down there checking cards.

if I just turned-up to a dive centre, totally unqualified, what sort of dive (I'm thinking mainly SCUBA here and in terms of depth/equipment) would I be permitted to go on, assuming I was medically fit and supervised while diving?

If you just want to try diving there's something called a "Resort Course".  You get a short classroom session, then some training in a pool...and you can go out into open water with an instructor the same day.  I don't know where they'd offer them in the UK...most of the water there is fairly cold and dangerous.  You might have to go down to Spain or the south of France.

Thescarredman wrote:If you're going to borrow from Voodoo's universe as well as pick his brain, be advised that there is a hard depth limit for normally-conditioned cyborgs of about ten meters.

As Alf noted, the figure is thirty meters, not ten. My apologies.

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