Negative entry vs Using a downline

[danvolker]

In Proust's novel À la Recherche du Temps Perdu, the character Swan wonders how the world would be different if people chose to read worthy books like Pascal's Pensées instead the trivia in the local newspaper for that period of time each day. Similarly, I wonder how many worthy books Dan could have written in the time he has devoted to his posts in this thread.

Dan, I dive a lot of the same wrecks as you describe in your posts, and I have dived them in pretty heavy currents--at least I thought they were heavy until I read your descriptions and realized I have really been missing something. At any rate, I have not experienced anything like what you just described in the quote above in quite some time, and that is because we have been doing things differently from what you describe on every occasion in which we have had a DM tie a line to a deep wreck. I am talking about dives with anywhere from 30-77 minute ascents for decompression. Perhaps you could describe this to process to the people with whom you dive--it's a lot easier.

The first time we did it this way was on the RBJ, a wreck at about 270 feet to sand. Because it is so easy to miss it with a hot drop, especially with the screaming current we had that day, the skipper gave the DM one shot at hitting it with the line, and he succeeded. When the captain described the plan, I asked how the line was going to come back up after the dive. He said he would send the DM back down. I said that we would rather unhook it ourselves, and he agreed. It worked great, as I will describe later.

On the shallower wrecks I have dived since then--like the Hydro Atlantic you mentioned--we use a similar procedure after the DM hooks in. The DM asks us for our planned bottom times and run times. He then times his descent back to the wreck to unhook the line while we are just beginning our ascents. In either the case of the divers unhooking the line or the Dm unhooking it as the divers begin their ascents, the result is the same. The line swings free until it hangs straight down from the ball that is now drifting freely in the current. The divers are also drifting freely in the current. Some will hold to the line lightly as they hold their stops. Some will "Okay" the line as it bobs up and down loosely between their fingers. Others will just hover in the water in the vicinity of the line. As divers finish their deco, they drift slowly to the surface next to the float, where they see the boat waiting for them. The boat positions itself properly in regard to the current, and the divers drift casually to the ladder. Piece of cake.

Since the boats you are on don't see to know about this technique, you might want to clue them in. Live will be much easier.

John,
I guess you missed the part where this hypothetical "you" .....has to come up early, maybe ten minutes before the main group due to low on air...so the line remains hooked for "your ascent"...
Also....The RBJ is normally easy enough to run a line to, or free descend on...it is not normally getting bombed by big gulf stream intrusion....which is what I am talking about... I also made it clear that the Pompano and Luaderdale wrecks typically have light currents on them.....

The Hydro is further north, and can run a bigger current by far on many days than I have experienced on the RBJ.
If you were to dive the Skycliffe, that would be a full tech depth dive, where the Gulf Stream is often screaming.....It can be light....but if I was to guess about doing 10 drops on it in the next 2 months, I would expect that at least 5 or 6 would be screaming current days. Since no one wants to have to abort a dive half of the time, you plan on the hot drop so no abort would be required.

And....John, c'mon, this example of line use was what we did in the early 90's on some of the Lauderdale wrecks where the Captain did not have the skill or inclination to hot drop the whole group....This IS NOT the technique I use today.....

And before you go on about how this group in your example is going to come up together--that is all well and good if you are diving as a team--then it is absolutely viable.
But this does need to be a team plan, or, if there are multiple groups ( 2's and 4's, whatever, with total of 12 to 20 divers) the plan must be that all are ready to go up at the same time....in practice, while this works perfectly with real teams, when you have just a bunch of multiple groups...sometimes it can work, and sometimes / more times, the divers are spread out all over the wreck, and someone will need to go up due to air supply, when other want ten more minutes.

Again, charter the boat yourself, keep it restricted to only your own team, and your plan is great.

On plenty of the boats that will do the RBJ or the Hydro, they will go with 20 tech divers, and some divers will jump in 10 minutes or later after the first divers went in....when this happens, only the last team/group in to the water, is likely to have an easy journey up the line.

The bigger the shipwreck, and the more divers that are not terribly aware of other divers outside of their own group, the more likely it is that there will be stragglers all over the wreck, when you and your buddy want to go up....especially if you are first in, and then the "least peripherally aware" divers jump in last -- and many minutes after you did......On a big wreck, it is not really feasible for a DM to swim the entire domain of two ships like the RBJ dive, to get all the stragglers with lots of gas left from a late drop... to form at the 25 minute mark--or whatever was set....

We ended up doing our own charters...so we could do what you suggest....most tech divers will not have this option on the RBJ and other tech wrecks....most of these Lauderdale wrecks are not screaming currents--not most of the time.

 

[lv2dive]

I would be more than willing to bet Dan's captains are aware of the option of tying in to the wrecks... I'm also willing to accede that may perhaps the best option for non-local divers not comfortable with getting down fast. That being said - if I were with Dan on one of the days the current is screaming, you can bet I'd want to do a hot drop as opposed to pulling down the line - the marginal chance of missing the wreck (with the hot drop) vs. the known effort of pulling down a line that deep, times a factor of at least 1.5 - for me is a brainer!

Dan, I dive a lot of the same wrecks as you describe in your posts, and I have dived them in pretty heavy currents--at least I thought they were heavy until I read your descriptions and realized I have really been missing something. At any rate, I have not experienced anything like what you just described in the quote above in quite some time, and that is because we have been doing things differently from what you describe on every occasion in which we have had a DM tie a line to a deep wreck. I am talking about dives with anywhere from 30-77 minute ascents for decompression. Perhaps you could describe this to process to the people with whom you dive--it's a lot easier.

The first time we did it this way was on the RBJ, a wreck at about 270 feet to sand. Because it is so easy to miss it with a hot drop, especially with the screaming current we had that day, the skipper gave the DM one shot at hitting it with the line, and he succeeded. When the captain described the plan, I asked how the line was going to come back up after the dive. He said he would send the DM back down. I said that we would rather unhook it ourselves, and he agreed. It worked great, as I will describe later.

On the shallower wrecks I have dived since then--like the Hydro Atlantic you mentioned--we use a similar procedure after the DM hooks in. The DM asks us for our planned bottom times and run times. He then times his descent back to the wreck to unhook the line while we are just beginning our ascents. In either the case of the divers unhooking the line or the Dm unhooking it as the divers begin their ascents, the result is the same. The line swings free until it hangs straight down from the ball that is now drifting freely in the current. The divers are also drifting freely in the current. Since everyone and everything is drifting at the same rate, the illusion is that you are not moving at all. Some will hold to the line lightly as they hold their stops. Some will "Okay" the line as it bobs up and down loosely between their fingers. Others will just hover in the water in the vicinity of the line. As divers finish their deco, they drift slowly to the surface next to the float, where they see the boat waiting for them. The boat positions itself properly in regard to the current, and the divers drift casually to the ladder. Piece of cake.

Since the boats you are on don't seem to know about this technique, you might want to clue them in. Life will be much easier.

 

[danvolker]

The first time we did it this way was on the RBJ, a wreck at about 270 feet to sand. Because it is so easy to miss it with a hot drop, especially with the screaming current we had that day, the skipper gave the DM one shot at hitting it with the line, and he succeeded. When the captain described the plan, I asked how the line was going to come back up after the dive. He said he would send the DM back down. I said that we would rather unhook it ourselves, and he agreed. It worked great, as I will describe later.

Actually, though the RBJ is certainly a serious wreck due to it's depth, and that it normally does have a current that has to be dealt with (normally this is a very light current by Palm Beach tech wreck standards) this is a deep wreck that will rarely provide a problem with line use....But, by the same token, when we started doing hot drops, that was the ONLY way we ever did the RBJ after this began, and we hit it dead on, every single time we ever hot dropped on it. And as you know--this is a huge wreck--it would be hard to miss if you can fall fast and have a good captain....We would only do this with one of the captains we liked.....
You said the DM got hot dropped....If a DM could do it, any of our team could do it.....

The fact that you found the RBJ easy, speaks to your high level of tech diving skill...but not to the current issue. This would require more than a few days of diving the wrecks like the Skycliffe or deep Hopper barges, or the 270 foot ledge off of Jupiter....or some of our other deep structures north of WPB.

 

[Greenjuice]

The line swings free until it hangs straight down from the ball that is now drifting freely in the current. The divers are also drifting freely in the current. Since everyone and everything is drifting at the same rate, the illusion is that you are not moving at all.

Quite taken by the idea of drifting with the line. Are you aware of a similar concept practised somewhere for the descent as well?

I'm thinking of the boat holding the hooked ball and line somewhat up current and then all drifting together during the descent.

p.s. I'm not a tech diver. Just curious to know. The wrecks at the depths I've experienced have had no problems with either free or line methods.

As an aside, one example of a hazard that has not yet been mentioned on this thread was at the Thistlegorm in the Red Sea. The hazard? Too many divers! Sometimes with half a dozen liveaboards and daytrippers with between 12 and 20 divers each. Lines seemed everywhere and a genuine risk of getting back to the wrong boat! I once got separated from my buddy on a night dive there, not by distance but because there were so many people in the way! You almost have to invent new procedures for this type of hazard, and since then my wife has always preferred us carrying unique identifying marker lights (Glotubes) on trips, just in case it ever happens again!


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[boulderjohn]

Quite taken by the idea of drifting with the line. Are you aware of a similar concept practised somewhere for the descent as well?

I'm thinking of the boat holding the hooked ball and line somewhat up current and then all drifting together during the descent.

You could do that if you didn't care where you ended up when you reached the bottom, in which case there would be no point in having the line hanging down.

When you do a drifting ascent, you don't care where you are when you reach the surface. You know that the boat will be following the ball to pick you up, and that is all that matters.

 

[Greenjuice]

You could do that if you didn't care where you ended up when you reached the bottom, in which case there would be no point in having the line hanging down

Yes, that would be just like a hot drop.
No, I meant with the boat holding the ball with some slack in the line up current, *after* the DM had hooked on. Then boat, divers, line and ball all drifting together with the line used as a visual reference for the descent (say to overcome misses in changing conditions, poor vis and minimise stresses on the descent).



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---------- Post added April 13th, 2014 at 08:01 PM ----------

I appreciate Dan's comment that if the DM can manage a hot drop so could any other experienced diver. Just wondering if this method might improve the hit rate for less experienced divers.


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[danvolker]

Yes, that would be just like a hot drop.
No, I meant with the boat holding the ball with some slack in the line up current, *after* the DM had hooked on. Then boat, divers, line and ball all drifting together with the line used as a visual reference for the descent (say to overcome misses in changing conditions, poor vis and minimise stresses on the descent).



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I think you mean a line being towed by something like this, with it's own navigation positioning system:






Get one of these, and you can dive with us any time

 

[boulderjohn]

Yes, that would be just like a hot drop.
No, I meant with the boat holding the ball with some slack in the line up current, *after* the DM had hooked on. Then boat, divers, line and ball all drifting together with the line used as a visual reference for the descent (say to overcome misses in changing conditions, poor vis and minimise stresses on the descent).

A lot of drift dives are done with hot drops, but the primary reason for that is to keep the group together rather than spreading out over the surface before everyone is ready to go down. All our drops in the Galapagos were done like that for that reason. There is no need, though, for a visual reference. Because your goal is to stay together as a group, the group's visual reference is the rest of the group.

Another difference is speed. On descent, you want to get down in a hurry. On ascent, you want to take your time.

 

[Greenjuice]

View attachment 181752

Get one of these, and you can dive with us any time

Need to get a crotch strap to hook it on to first!



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[Splitlip]

I'm in construction. OSHA mandates that all ladders are secured. Well, how does the first guy do that?