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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.
Besides that, what are all of these OW divers doing at 90ft when there PADI certification clearly states a 60 foot limit?
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.
Experience.Why do you think it wouldn't reach the 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.Too short of a line or are you assuming the current would drag it fast enough for it to not surface?
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.I have no idea how fast a current will cause a freeflow in a reg.
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.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?
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.
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.
@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.
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?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.