DevonDiver
N/A
Not sure whether this should be here or technical...
Just did my wreck course and are qualified to dive to 40m.
Definitely here.
At the moment I am using a standard BCD and tank, but am finding I am gas limited for the deeper dives.
The first thing to do is examine your SAC. Deep wreck diving is quite an advanced pursuit, so every dive should have a proper gas plan. Prior to getting into the water, you should have a clear understanding of your gas needs for the dive, your contingencies and your turn-points.
There is also the concern about not having redundant gas for entering a wreck.
That's quite a big concern, when diving deep in an overhead environment. The ability to donate/recieve gas from an attentive buddy is the core of the recreational diving system.
However, the effectiveness of the buddy system can often be compromised when deep/wreck diving. Restrictions inside a wreck can mean that air-sharing can become difficult, or even impossible, when exiting the wreck.
In addition, most recreational wreck divers don't recieve any training in the gas planning procedures needed to ensure that they have sufficient gas to share for exit and ascent (gas matching within turn-point calculation).
Proper gas redundancy, to allow unsupported exit and ascent from a wreck is a critical issue.
On the other hand I do a fair bit of shore diving, and in those cases I normally don't need the extra gas.
If you're going to be involved in specialist diving activities, it often involves an acceptance that one single configuration is no longer going to be ideal for all of your dives.
Advanced diving activities mean more expenditure on kit and training.
The first option would be to do a sling/stage tank. the advantage of this is that I could continue to use all of the existing equipment, with minimal changeover, but will meet the extra gas/redundant gas requirement. The disadvantage is that I would have to buy the doubles in the longer term, so it is only putting off costs.
Sling tanks are not ideal for wreck penetration. The obvious issues are entanglement and cross-section (getting through restricted areas).
With a single tank of back-gas, you'd need a sufficiently sized pony/stage to ensure you could exit the wreck and ascend. Unlike normal open-water diving, the fact that you could be deep within the wreck, in limited viz, possibly entangled etc... means that your contingency gas calculations would need appropriate padding.
Basically...it'd need to be a big stage cylinder.
the second option would be to go to the full doubles. The advantage is that this is needed in the long term (probably). The disadvantage is that some of my gear (yoke 1st stage) would be made redundant, and it would be harder to convert back to a normal set if I was doing a shallow dive....
This is why technical divers will always warn potential tech divers about the large cost involved.
If you're going to be penetrating wrecks in deep water, then you need the proper kit and training to do it. Any short-cuts in this are made at the expense of safety.
What would your suggestion be?
If you're serious about proceding into tech diving and you also intend to conduct deep wreck penetrations, then I'd say it's time to invest in the proper equipment.
Get a BP&W and doubles. Save your jacket BCD for the shore diving.
Using doubles isn't the 'preserve' of technical divers. They are a valid choice for any diving scenario that requires a considerable amount of contingency/redundant gas.