Seems that I am in the minority staging my deco gas, so I will add that I tend to stage it slightly inside the wreck, clipped off to my line so as to be out of sight of the vacation diver...
I guess you have to balance the risk of potentially having to re-enter the wreck to retrieve the cylinders (if exit forced from a different egress point) against the risk of interference to your cylinders by these murderous passers-by?
I don't think I'd ever stage a tank once entered into the wreck, either inside the entrance, or along the way at a restriction. I'd either stage it outside, or carry it all the way through. If I couldn't get through a restriction safely because of the tanks, then I'd count it as a 'progressive' exploration and return next time with a different plan.
Is there REALLY that much risk of recreational divers interfering with (well marked, labelled and secured) tanks?? Even if you leave a warning slate on them?
As I mentioned in the other thread, on one dive my buddy indicated that he wanted to drop the bottles so we could fit through a particular restriction. This was not something we had planned prior to the dive, and there was no particular reason for doing this other than, I supposed, the inherent fun in getting through such a restriction. I did not hesitate to say no, and he did not push it once I did.
That's something I'd resist also... leaving tanks at a restriction, inside the wreck, seems very risky to me.
In or out... no compromises.
and oh yes, here I am "learning" that 3 stages plus doubles don't always fit (admittedly this was in a cave environment). I corked myself good and solid and neaded a shove from behind.
Having moved to sidemount, the issue of passing restrictions becomes a lot more flexible. This increased capacity to venture into smaller areas is one of the reasons why I am re-visiting my own perspectives on the staging of deco tanks. I now have the option to move more freely around inside a wreck - and carrying more than 2 cylinders during that phase of the dive would somewhat defeat the goals I am attempting to achieve.
I believe the need would have to be severe. I would not have done the Chatterton thing (taking off the back gas) on that Uboat (in Shadow Divers). Identifying a mystery boat would not be enough of a reason for me to take that kind of risk--not even close.
John, what do you identify as the big risk inherent with removing/replacing equipment in order to pass through a restriction? Obviously, the description of John's penetration in Shadow Divers is pretty extreme..mainly because of the visibility issue on return through the restriction. Increased risk of entanglement, sounds the worse issue to me.
Have been looking at options for this - including the use of micro-sidemount or no-mount single cylinder, in addition to back-mounted doubles.... as a solution to pre-determined goals on a planned and rehearsed dive. The concept of a rig-under-a-rig... lightweight harness (little/no buoyancy), with a suitably sized cylinder/s worn underneath the primary rig. Reach the restriction, remove the primary rig.. continue onwards with the 'secondary' rig. Deco cylinders left at the primary tie-off. Basically, peeling away layers of an onion through progressive stages of penetration - and re-donning those layers upon egress. Obviously, this relies upon returning upon the inwards route (same risk as cave diving) and involves complicated gas management/planning issues. Crazy talk?
All hypothetical at this point - because sidemount config has answered most questions, and has opened up sufficient options for access in all cases thus far. At most, I might remove a single sidemount cylinder and progress with one only... my body size being the main restrain on the spaces I could pass through. Removing the sidemount rig itself and going onto a 'no-mount' with smaller cylinder (i.e. 'British style cave mounting olde style') would only gain me an 1" or so...
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