What do folks make of this one...

[mathauck0814]

I realize Ken said it was the UB-88, but is there anything actually in the OP that indicates that it's the UB-88?

Yes, you would shot line and live boat the UB-88. A 120' wreck, not necessarily.

 

[MaxBottomtime]

He mentioned seeing the anchor while leveling out at 120'. The top of the conning tower is in 165', so with good visibility they would be able to see the anchor from 120'. The author, Nick Ambrose has dived the UB88 several times since I first shared the numbers. I'm pretty sure that's where they were diving.
Diving the UB88 Submarine: California?s WWI Submarine | Scuba diving and skin diving California and beyond
The UB88 lies in the precautionary zone, an area between shipping lanes where ships may travel to head into Los Angeles or Long Beach Harbor. It is also within a half mile of the route the Catalina Express uses between L.A. and Two Harbors. I have dived it three times and never had a problem with traffic, but I certainly would not dive it with a choppy surface or currents. At six miles south of San Pedro, the prevailing easterly currents would take you toward Orange County if you made it that far.
If I saw the anchor dragging, I would abort the dive right then.

 

[mdax]

Wow, it always amazes me when it's not just one idiot but a whole group

 

[RJP]

Wow, it always amazes me when it's not just one idiot but a whole group

"Birds of a feather..."

 

[dumpsterDiver]

Gear = Halcyon Pathfinder Reel with 400ft of heavy line and Halcyon 6ft "Super Big" closed-circuit SMB, finger-spool with 150ft of heavy line, 80lb closed-circuit lift-bag, slate or wetnotes.

Technique is pretty simple:

If you can't get back to upline (or get back to upline, and it's gone) shoot the 6ft SMB to the surface, tie it in to the wreck, ascend on the line doing scheduled stops along the way. If you can, put a note on the bag to let the surface know what the deal is.

Of course, the most obvious complicating factor would be how much current is running, and related would be how deep is the tie point to the the surface. If there's a ton of current, and you're deep this set-up isn't really ideal. But if you have NO other up-line available, it's better than a free ascent drifting the whole way. I'd ascend as far as I could and complete as much obligation while tied in as I could. If - and this is unlikely - I'm so deep that the SMB doesn't get to the surface and/or I'm flapping in the breeze so far down-current that I couldn't make stops the rest of the way on the line tied into the wreck... I'd shoot a bag and do the rest of my time adrift. I guess with 400ft of line, there is a current speed at which the SMB and/or I couldn't reach the surface "on the the line" but I would think that would be a pretty ripping current. As has been mentioned above with a 3:1 scope ratio, 400ft of line covers me pretty well.

I suppose there's always a risk that the current could be so strong that the line would break. But I inspect/replace my line as needed to minimize that risk. Plus, at some point, if the current were that strong, I would have the good sense to thumb the dive from the outset, cut the dive short to minimize or limit deco obligation, not stray far from the anchor line, or both. The deepest dives I tend to do are in the 150ft range here off NJ, so 400ft of line should be OK. I've only had to employ this approach once, from 130ft, and there wasn't much current at the time. It was uneventful, other than needing to go untie my line (and retrieve a bag of scallops) during my second dive. I've seen a few other divers need to do this as well. All were uneventful proceedings.

Thanks for the reply. I am skeptical that your method would work in a strong current. I think you would be susceptible to being sucked down from a current as you tried to ascend on the float. If that happens and you have to drift, you just cut the nylon line and leave a few hundred feet attached to the wreck?

If you do make it to the surface on the floatline, you just cut the line and leave a few hundred feet of nylon line on the wreck?

 

[Ken Kurtis]

I realize Ken said it was the UB-88, but is there anything actually in the OP that indicates that it's the UB-88?

FTR, MaxBottomtime said it was the UB-88. I said it was 190' deep without mentioning the name. That being said . . .

I know who the story is about. The wreck IS the UB-88 and my further understanding is that the diver in question never did seek hyperbaric treatment.

- Ken

 

[Kevrumbo]

In regards to the DCS Incident, the following is the proper emergency procedure for all SoCal commercial diveboat operators that EVERY DIVER should be familiar with and adhere to:
http://www.scubaboard.com/forums/so...dcs-age-always-go-la-county-usc-catalina.html

What a big unfortunate misunderstanding!!!

Standard Operating Procedure is to un-hook the anchor -AT THE END OF THE ALLOTED BOTTOM TIME- and do the deco stops staying with the loose/dragging anchor & line while ascending along it. Pop the SMB as needed. . .

If this was in the shipping lanes to LA/Long Beach Harbor, the boat crew should tie off a marker buoy float to the anchor line topside, and freely follow it untethered -just in case the diveboat has to dodge oncoming merchant container ship/tanker/cruiseship traffic.

 

[RJP]

If you do make it to the surface on the floatline, you just cut the line and leave a few hundred feet of nylon line on the wreck?

We'd clean it up next time, but if the choice was "free ascent" or "coming up a line" I'd choose the later and clean it up later. That said, with little current there's a way to wrap the line so that you can reel yourself up the line and then bring it up behind you after you surface.

---------- Post added May 29th, 2013 at 06:08 AM ----------

We'd clean it up next time, but if the choice was "free ascent" or "coming up a line" I'd choose the later and clean it up later. That said, with little current there's a way to wrap the line so that you can reel yourself up the line and then bring it up behind you after you surface.

Our wrecks here are so covered with lines, monofilament, abandoned fishing tackle, traps, nets, etc that an added piece of line out there for a little while is really of no consequence.

 

[peterbj7]

I find this thread interesting. So many variants on what I had thought was a fairly standard wreck dive. I do find the slick language used by some a problem, as what may be standard terms in one part of the world may be gobbledegook in other places. In particular, what is "live boat" as a technique, and what exactly is a "Jersey upline"?

Just a few comments on detail. In my experience most wreck dives are done with a shotline, not an anchor. A skilful captain can usually position the shot on the upstream side of a wreck so that it jams effectively, but by slackening the line and steaming against the bottom current he can usually free it. That's SOP for most pf the wrecks in and around UK waters. On a few occasions in the US when I've done deep wreck dives and the captain used an anchor the last diver up always unhooked the anchor from the wreck and hooked it into a loop on its own line maybe 30ft up. The divers then ascended that line, sometimes switching to a lazy shot at an appropriate depth.

We do dive wrecks in the English Channel, which is an incredibly busy channel with giant ships passing through. There we descend to the side of the wreck, outside the shipping lane, swim over to the wreck and dive it, then swim back sideways before we start ascending. By definition these have to be free ascents so we only make the dives when current conditions are right. At no point is the dive boat over the wreck.

Big ships can have draughts of 50ft or more. No permanent wreck marker is possible.

My DSMB reel carries 40mtr of line, and I used to use one with 50mtr. I have never known anyone use significantly longer. If there is no fixed ascent line available it is customary in deep water to ascend free until the DSMB will reach the surface, which typically is maybe 70-80% of the line's length (depending on currents). It is obviously desirable to have the DSMB on the surface sooner rather than later so the boat has a chance of seeing and following it.

I have never heard of anyone tying a DSMB into a wreck and leaving the line attached to the wreck. Apart from the cost, how do you know it reached the surface? And as you ascend do you have another DSMB to deploy?

The bulk of my UK-and-close wreck diving has been on wrecks down at around 40-70mtr. Most days the first dive will be to 55mtr or so. I do recall having to make a free ascent (with DSMB deployed) from 90mtr when the pinnacle I thought we were tied into turned out to be the wrong one. That was a long hang that took me about 3 miles. Fortunately (though this was actually planned) there was minimal shipping where I drifted.

I only ever use finger reels for static work on/in wrecks and caves. I would never try to use on for ascending as the risk of entanglement is too great, though I do see people using them for just that.

Inside wrecks I prefer to use braided steel line, not fabric. There are too many sharp edges inside a wreck to use fabric safely. I learned that lesson the hard way from someone else's near fatal mistake.

 

[TSandM]

"Live boat" means the boat is not anchored, and is free to follow divers.