Halcyon Backplate Question

[Uncle Pug]

You should be able to swim your system to the suface without gas in wings or the ability to add
gas to your drysuit.

... I'll have to get together with Peo for some lessons on swimming up loaded 104s with empty wing and the suit squeezed.

 

[Peo]

[...]
I've also done the test of going down to 30 ft with full tanks and stage, emptying the wing and drysuit to absolutely nothing, and then swim the rig up to the surface.

My memory says we had our stages with us on the dive, but checking my logbook it doesn't say anything about it, so to err on the side of caution I'll assume that I *didn't* have my stage on this dive.

Anyways ...

/Peo

 

[Uncle Pug]

On the issue of swimming up double steels, especially heavy ones like the 104s:

The advice not to use double steels with a wetsuit has to do with the difficulty of swimming them up without buoyant help from a wetsuit at depth in the event of a wing failure.

However if you could swim up a full set of steels to the point that the wetsuit begins to regain buoyancy you would be in much better shape that the poor fellow who has a total flood of his drysuit and not only needs to swim them up but tread water with them once on the surface.

 

[Peo]

On the issue of swimming up double steels, especially heavy ones like the 104s:

The advice not to use double steels with a wetsuit has to do with the difficulty of swimming them up without buoyant help from a wetsuit at depth in the event of a wing failure.

However if you could swim up a full set of steels to the point that the wetsuit begins to regain buoyancy you would be in much better shape that the poor fellow who has a total flood of his drysuit and not only needs to swim them up but tread water with them once on the surface.

It is also worth pointing out that swimming up a set of double 104s without any buoyancy aid is no easy task, and I doubt if I could go through any kind of successful deco schedule with a totally flooded suit and no wing without some serious help from a buddy. Not to even begin thinking about gas consumption...

I think swimming up your rig is mostly a gedankenexperiment and something to do as a very last resort shaving off all your deco but *perhaps* reaching the surface before you're out of gas, or to check that you're not overweighted....

 

[Doc Intrepid]

I think 'swimming up your rig' is fodder for internet group gropes.

If you can do it, bully for you. If you can't, not to worry.

The core tenet of serious diving is the team. What resources and assets are available to each diver individually are also available to the team as a whole.

If a diver has a problem, the team has a problem. The team solves the problem.

A guy who opts to swim up a set of 104s alone and then try to stay on the surface once he arrives is a speciman from the shallow end of the gene pool.

 

[Uncle Pug]

I've never tried using a lift bag for buoyancy on an ascent; I can only imagine the issues.

... but perhaps it is a skill worth having. Even if you can swim your doubles up with a failed wing, holed suit and separated buddy... keeping yourself at the surface might prove difficult.

Every so often when I find stuff like anchors and lead down-rigger balls I will attach a bag to them and take them along for the rest of the dive.

Ascents aren't too difficult if you are using a short bag with the dump at the top... but beware of using long dive markers with the dump near the bottom for carrying and ascending with stuff.

 

[Uncle Pug]

Back on topic.... wing size.

The wing capacity you need during the dive is actually fairly small... just enough to offset the weight of the gas that will be used if you are diving a balanced rig.

However that is not the total picture. Not all combinations of gear can be balanced so finely. Especially as you start adding things like deco bottles, argon bottles, scooters, cameras, V-weights to offset extra thermal protection, ect.

And then there is the issue of what you will need for surface conditions, which for me makes the 40# wing sub-optimal. Either the 55# or the 70# work for me and like I said in my first post.... when the surface conditions get lumpy I like the 70# wing.

 

[VTernovski]

ok, I am getting confused here. in my DIR-F class it was stressed that unless you are diving a cave or a quarry where you can literally walk out, if you can't swim up your doubles, then you shouldn't be diving those particular tanks in that configuration in the open ocean. Which was suggested that for open ocean, Aluminum 80 doubles is nearly the ideal choice. According to some posts here, it almost sounds like it's great if you can swim them up, but if you can't then it's ok too.

please note I am talking about diving coldwater in a drysuit here.

 

[Uncle Pug]

Back off topic.

 

[Doc Intrepid]

ok, I am getting confused here. in my DIR-F class it was stressed that unless you are diving a cave or a quarry where you can literally walk out, if you can't swim up your doubles, then you shouldn't be diving those particular tanks in that configuration in the open ocean. Which was suggested that for open ocean, Aluminum 80 doubles is nearly the ideal choice. According to some posts here, it almost sounds like it's great if you can swim them up, but if you can't then it's ok too.

please note I am talking about diving coldwater in a drysuit here.

To clear up confusion, let me try to state my opinion in a different way.

In the absence of data immediately in front of me, I will estimate - but the point is that a drysuit diver in cold water performing a trimix dive to, say, 240' - 260' could conceivably jump in with a set of high capacity steel doubles, an argon bottle, quite possibly an 80 of travel mix, and possibly (2) 40s of 50/50 and O2. If you add up the weights of the compressed gas in those tanks, you'll find that our hypothetical diver might be over 32 lbs negative upon jumping in.

Suppose, hypothetically, our diver is able to swim up his set of doubles (alone) with his suit and wing empty.

Even if this is the case, our real-world diver is unlikely to jettison all his gas should his wing fail 1/2 way through his dive. First, he has a deco obligation. Throw away all his extra gas (weight) and deco becomes extremely problematic.

More importantly, he is not alone - but is a member of a team. That gas may be necessary to bring the entire team back, while dealing with this particular difficulty. The gas is not merely his resource, but constitutes a team resource.

The point is that whether that diver can swim up his doubles or not becomes a purely academic debate under most actual conditions. The point is that he isn't wearing ONLY his doubles, and that he can't safely jettison the rest of his gas or equipment. Moreover, he's not alone. The members of his team are there to support him.

To be able to swim your tanks up is an ideal situation for an individual diver, and I am not trying to diminish what any GUE DIR-F instructor emphasized.

But...given the circumstances surrounding most real-world technical deep dives, it becomes a moot issue. The bottom line is that the team must bring back the team. They may very well need that gas, and ought not to unhook it and drop it into the abyss. There are other options that make more sense - such as using redundant bouyancy as a team to bring back the team. In the final analysis, that is what 'doing it right' is all about - thinking though a situation (in advance) to arrive at the most efficient and effective solution as a team.

Having a stricken diver suddenly jettison all his extra kit and go balls to the wall for the surface swimming up his balanced rig is unlikely to be the most efficient and effective solution for that particular failure.

It isn't that the concept of a balanced rig has no merit. It's that under many sets of technical diving environmental parameters the concept is immaterial. IMHO there are other more productive team-oriented response options.



<You will now be returned to your regularly scheduled debate over wing size!>