grazie42:
My questions to Boogie711 still stand though...I actually looked at an OMS wing today trying to see what he meant with: "Why would anyone want to rig an inflator behind them". The one I looked @ didnt have bungees so as its (obviously) a personal choice whether to leave them on or off that argument seems very weak (and even then the piece referenced above doesn't seem to dissaprove of them)...
There are always rational arguments behind DIR recommendations. Whether you choose to agree with them or not, or whether they appear to apply to the diving you often do, is a different matter.
Several concepts apply to bungeed wings. As the topic has been thoroughly beaten, I'll be brief:
Should you ever need to try to inflate the wing on the surface orally, you will be trying to blow into the wing against the pressure of the bungee cord. As any situation where you need to inflate the wing orally implies that you aren't having a good day to begin with, additional stress is not likely to improve your survival odds.
The bungees pull the wing in at defined 'bands', thereby trapping air in between bungee bands. If you are attempting to fine tune your bouyancy using the left rear pull dump, it can make it difficult to balance right and left. The air does not circulate as freely inside the wing.
The bungees are supposed to 'gather' the wing in, thereby supposedly reducing drag. In video footage, however, wings without bungees 'fold up' against the twinset on each side, presenting very little drag along the longitudinal axis of the diver.
There are other elements as well, but these are some primary thoughts. (Um, and why would you desire to buy a bungeed wing to then remove the bungees leaving all those grommeted holes? Just buy one without bungees to begin with...)
In terms of diving steels wet, this has been addressed above. Suffice to say that with two deco bottles and steel twins the total excess weight a diver can have at the beginning of a dive can be greater than 25-30 lbs. A wing failure at the start of the dive, after the wetsuit has been compressed at depth, can leave a diver in excess of 30 lbs heavy, no wing, and even if the diver jettison's the deco bottles, they are still trying to swim up 20+ excess lbs with no bouyancy at all. Unless they remove the steel doubles and do an ESA, their options are decidedly limited.
One argument against dual bladders is the distressing tendency for some LP inflators to suffer low level leaks. If you connect both LP hoses to inflators, and you keep getting lighter and lighter causing you to need to dump gas to maintain bouyancy, now you need to determine which inflator is leaking. Some divers don't hook up the right inflator. Some divers secure the inflator that isn't hooked up along their right side, bungeed to the bp. Now if there is a problem they must access the LP inflator on their right, then connect it, while dealing with other task loading resulting from the failure, which can become problematic. It isn't necessarily that there is no place for dual bladders. It is that they require a more robust planning and training effort.
Obviously, whether you find these arguments compelling or not will depend on your circumstances. But these are some of the arguments being referred to earlier.
Regards,
Doc
