Time between 130-foot dives?

[whiporee]

6x6x6 safe is going to require quite the lift bag to get it out.

Yeah, I know. That's why she's got to make a bunch of dives to attach them. The safe is in the engine room, so she's going to have to guide it out, and then pull it the quarter mile to the cut -- she'd got to time the tides and all that stuff.
She's the only one who saw the boat go down in the middle of the night, in a storm and doesn't want the other salvage companies in the area to know about it (it didn't sound a mayday or flare or EPIRB or anything). She's exploring the wreck and sees a box in the engine room that shouldn't be there.

Once she gets the box out, she gets it open and realizes it's something bad (in my mind it's a nuke, but I'm not sure I'm going to tell the reader that, or that she ever gets the box open). She's got backstory as a hostess on a boat owned by a Saudi family, so she feels she can't go to the government for fear of being considered a terrorist herself, so she decides to hide the box and then refloat the sunken boat enough so she can get it further in the sound and sink it again. That way no one will ever know she was there. Of course, someone finds out, wants the box, and that's why she needs a reason to eventually kill the bad guys in order to get away.

There's some other stuff, but that's the gist. Any ideas that could help?

 

[tphelps]

Hmm sounds like there are lots of skills involved in this salvage.

My first and foremost recommendation is not for her to exceed her level of training. Nothing is worth loosing her life over (at least I hope not!). But seriously if recovering this safe soon is a priority, I'd recruit some trained tech divers that has experience in overhead environments. If you are talking about recovering this from inside the vessel then you are going to need a line to penetrate the wreck, making necessary tie offs, moving without silting out the viz then after all that you still need to attach the lift bags! Wouldn't it be easier to ask the original owners the combination first and retrieve what was in it? (lol)
If she IS set on recovering the item might I suggest compartmentalizing the mission? I'm a tech diver so I would make these deco dives but if she doesn't have the training for mandatory decompression, here is another scenario (assuming she has overhead training): I would do 1 dive to just assess or even map the wreck. If she is familiar with it already, take a reel down and lay the line entering to where the safe is. That way she doesn't need to spend additional time laying the line each time. Since she knows the dimensions of the safe, I would seriously find something of similar size (not necessarily weight) and sink it in shallow confined water (maybe a personal swimming pool). Practice, practice, practice how she going to attach the lifting device so you can do it blindfolded because if there is a silt-out she literally wont be able to see anything! I'm assuming she will have a buddy on this, right? When making the plan, run through every minute of the dive. What will the buddy be doing the entire time?

Like I said, I do not encourage going outside her level of training. I'm just giving my best advice because I'm not exactly what kind of experience she has. But a deep dive, penetrating a wreck while recovering a SAFE? That is a lot of task loading and she should be well prepared progressing the mission in small increments.

Hope this was helpful, safe diving!

 

[Stoo]

Clive? Is that you?

 

[whiporee]

Clive? Is that you?

LOL!! I wish!

Thanks for all the input, everyone. I appreciate it.

 

[danvolker]

Hi everyone --

I'm a novice recreational diver who hasn't gone out in a decade. I'm also a novelist, and my protagonist works in salvage. She's trying to being a large (6x6x6) safe out of a recently sunken megayacht without anyone knowing what she's doing, so she has to do it all clandestinely. The boat's in about 130 feet of water, and I'm wondering how long she would need to wait between her dives. Could she do them on consecutive days? I figure she's got about 10 minutes of bottom time each dive without decompressing stops, so it'll take a several dives to attach the flotation devices.

Also, if anyone knows, I'm thinking of her killing the bad guys in the end by attaching one of those flotation devices to them at 130 or so feet and inflating them -- sending them up fast. My thinking i that if someone went up that fast without a stop, they'd either get the bends bad (in open water, with a cut on their leg, so sharks) or an embolism. But that's not crucial yet -- I can find another way to kill them -- but I thought that might be cool.

Any information or advice anyone can offer I'd sure appreciate. Thanks

For the clandestine nature of the dive, your girl would be much better off using a set of doubles...and doing one longer dive once she wants to bring up the safe....She can stay down for 30 minutes, and do deco at 20 feet with pure O2 for 12 minutes --and be fine.

Kill the bad guys by setting a Lion-Fish trap for them in the passageway--anyone that swims through without knowing to avoid the trip wire, gets a net filled with a dozen big lionfish, falling on them, and then the lionfish stinging them for a horrifying end to their transgressions

 

[whiporee]

Okay, I'm back.

I've decided that my girl, while trying to get the safe out by herself, will get stuck in the engine room because the safe will block the door. The end.

Not really. But she'll be down longer than she had planned, an in order to squeeze out, she'll have to dump her gear. So ... and again, thank you, how long can I have her be stuck without getting wiped out by the time she gets to the surface, and, while I remember that you can do a free accent without your gear, would she realistically be able to do that from 120 or so feet? As she's coming up, I can introduce the concepts of embolism and that, so it's not new when I bring it back.

 

[danvolker]

The still living Dive legend of Palm Beach, Frank Hammett--guy that found all the diving reefs of Palm Beach ( now in his nineties I believe), used to do "back to back" dives on the 135 foot deep Hole in the wall, this being his favorite spearfishing site in the 1960's...
Frank would breath a steel 72 down to zero in about 15 minutes, free ascend from 135, and then grab another tank--and do this again..maybe a 15 or 20 minute surface interval at most. He was never bent as far as we can tell....I dove with him in the late 70's and all through the 80's and 90's.


Personally, I have done a free ascent from 130, just to see how it felt, and I found it quite easy....though I would not be inclined to WANT to do this after being down 15 minutes--this increases the chance for most people to get a DCS hit--even though it never bothered Frank.

 

[Darkforeboding]

Lord Almighty! a 6 x 6 x 6 foot safe? Depending on what it's made of, it could weigh 50,000 lbs. No, that isn't an uneducated guess, I've moved safes and vault doors. Might be a better idea to kill the bad guy by cutting the lift bags and dropping a safe on him underwater.

DFB

 

[nimoh]

Lord Almighty! a 6 x 6 x 6 foot safe? Depending on what it's made of, it could weigh 50,000 lbs. No, that isn't an uneducated guess, I've moved safes and vault doors. Might be a better idea to kill the bad guy by cutting the lift bags and dropping a safe on him underwater.

DFB

If it's air tight and doesn't leak (i.e. vacuum pressure doesn't suck in water) then it wouldn't be out of the question for one person to lift it with lift bags, but not sure what you would do with it once it is near the surface hanging from the lift bags.

If the plan is to lift it onto the boat with a crane, might as well lift it all the way from the bottom.

 

[whiporee]

Lord Almighty! a 6 x 6 x 6 foot safe? Depending on what it's made of, it could weigh 50,000 lbs. No, that isn't an uneducated guess, I've moved safes and vault doors. Might be a better idea to kill the bad guy by cutting the lift bags and dropping a safe on him underwater.

DFB

My basic research showed it would be about a ton without anything in it. You think that's too low?