What if...? Dive Planning & Trust Me Dives

[MRadke]

Besides that, what are all of these OW divers doing at 90ft when there PADI certification clearly states a 60 foot limit?

 

[fjpatrum]

In that kind of current, your DSMB will never reach the surface from depth. If it does, then it's going to pull you up with it and will act as a sail and take you for a ride.

Why do you think it wouldn't reach the surface? Too short of a line or are you assuming the current would drag it fast enough for it to not surface?

I have no idea how fast a current will cause a freeflow in a reg. My assumption is that I would want the boat to have some idea where I am as soon as possible. If I had reason to believe my SMB wouldn't surface from depth, I'd probably try to do the same things I mentioned before but wait until safety stop depth to deploy the sausage. So, what's a good rule of thumb (if there is one) to determine that choice?

 

[fjpatrum]

Besides that, what are all of these OW divers doing at 90ft when there PADI certification clearly states a 60 foot limit?

That is a recommendation, not a rule.

 

[MRadke]

That is a recommendation, not a rule.

I was being sarcastical because of the feed back that I received for my responses from the first scenario.

 

[Jax]

The problem with letting go and deploying the DSMB is (1) does the crew know what to look for?

1) Crews would likely be familiar with DSMB.

To clarify the question, "does the crew know what to look for?", per a thread where people were discussing being adrift in the ocean, the crew and pilots opined that a diver should let the crew know what s/he is carrying.

A diver in 3' swells with a 3" x 3' SMB isn't very noticeable. In my case, "mine's bigger!", but not many new divers would consider carrying a large and somewhat clumsy-to-deploy 9' SMB.

 

[Cave Diver]

Why do you think it wouldn't reach the surface?

Experience.

Too short of a line or are you assuming the current would drag it fast enough for it to not surface?

A 100' line in no current will hit the surface from 100'. The more current you have, the more scope you'll need on the line, because the bag is going to ascend on a diagonal as the current carries it.

I have no idea how fast a current will cause a freeflow in a reg.

Me either, but I can tell you that current enough to make a detuned Dive Rite reg free flow is enough to pull a fullsize beer keg attached to a 5/8' line 3' under water when a couple of divers are hanging on the line.

My assumption is that I would want the boat to have some idea where I am as soon as possible. If I had reason to believe my SMB wouldn't surface from depth, I'd probably try to do the same things I mentioned before but wait until safety stop depth to deploy the sausage. So, what's a good rule of thumb (if there is one) to determine that choice?

A lot of variables can affect the choice. One point of this particular exercise is to give you some thoughts about what you can do in advance (like Flots mentioned) to avoid this situation to begin with.

 

[Jax]

I would have the conversation about the DSMB with the crew before ever doing a drift or high current dive, personally. I haven't ever deployed my SMB yet, but it's a 6 footer, with both orange and yellow colors and a "reflective" patch too. I'm not sure why you think it would be the most dangerous. The SMB won't cause you to be pulled more by the current than you would otherwise since it's going to show significantly less surface area for drag than you would as a diver. Am I not considering something?

Thanks for the idea about staying behind/below the structure of the wreck though, I hadn't thought about that. With 1800 PSI in an AL80 I think one should be able to last a few minutes at ~60 FSW and still have some spare gas for a safe ascent.

Absolutely let the crew know your equipment, even if there isn't a current - you never know what may come up.

However, to release oneself from the wreck, when this 'sudden' current came up, to surface God knows where (boat traffic?), and in what kind of conditions, is pretty iffy, in my book. You are then "hoping" you'll be found, and in my book, "Hope is not a method."

Therefore, one would have to make a call on when you don't have the gas to do anything else but let go and ascend.

 

[Kenny13]

I've done dives on both the Oriskany and the Spiegal where there was a ripping current and there were divers on the boat with only OW certs. Whether that's a fluke or common I can't say.

Can't speak for the Spiegal but most, if not all, the boats I've checked out for the Oriskany will take OW divers but require a minimum of 20 logged dives with at least 2 deeper than 80 fsw, and if I recall correctly one of those has to be within 6 months of the planned dive date. Question is, how strictly do they abide by those requirements????

I'll be the first to admit that I am not ready for either of those dives, although Oriskany is my dream dive. I plan on getting considerable more experience before I even consider going deeper than 60 fsw, and I really want to get better with trim, buoyancy, gas consumption, & gas management before I would consider myself comfortable enough for most boat dives. Really, I want to get better at those things before I plan on taking my AOW. And actually, I'm considering using the boat diving part of my AOW as my first boat dive but that could change depending on how things go in the meantime.

 

[Cave Diver]

@Cave Diver: Are there other moorings tied into the wreck? I've never dived the Spiegel Grove.

If there were a convenient mooring line nearby, my buddy and I could try to ascend using that. Although it wouldn't bring us directly back to our boat, it would get us to the surface without getting completely blown off the wreck. Once on the surface, we could inflate our signal tubes to get the crew's attention.

The SG does have alternate moorings. If you look closely at the picture I posted you might be able to make them out, along with relative depths (ctrl + may help). I purposely left mention of those out of the scenario, because I based this scenario on a combination of 4 different dives I've done. 2 had alternate moorings, 2 did not but the SG was probably one of the most recognizable and the most likely to end up with OW divers on it.

Alternate mooring lines are a good potential options for the SG (and it happens quite a bit), but I'd like to see other thoughts in case they aren't available.

 

[fjpatrum]

A 100' line in no current will hit the surface from 100'. The more current you have, the more scope you'll need on the line, because the bag is going to ascend on a diagonal as the current carries it.

Yes, this is all basic physics but the SMB will eventually surface, given enough line. I was trying to determine if you believed (through experience I don't have) that the current would still keep it under. So you're assumption is that the line is short or that by the time it did surface it would be too far away?

Having divers "weighting" the line would definitely have a negative effect on it surfacing well.