Disclaimer: I think this is a kooky idea too -- I think the best way of providing unlimited breathing media for cave divers would be to start using top-of-the-line rebreathers, not dragging umbilicals. However, I'm entertained enough by the thought of dragging umbilicals to consider what it would take to make it feasible.
Make me an umbilical that's almost as thin and flexible as cave line, and a fool-proof system to deploy it, and you might have a winner. If there were some way to make the umbilical the size of a headphone cord, it might even be reasonable. It would obviously have to carry considerable pressure to be able to supply a diver's flow rate. High-pressure hoses tend to be very unflexible, but technology has solved bigger problems.
Could we envision some sort of "environmentally-friendly" pulley/router type device that you could clip to the wall, or the gold line, and pass your umbilical through to route it through the cave? Climbers have protection, in the form of permanent bolts or temporary cams, anchored into the wall. As they pass each anchor, they clip the rope into the carabiner. A similar deal could work in a cave -- you could have anchors placed at strategic points in the cave, and divers would clip their umbilicals into the anchors as they move into the cave.
I cringe to think at how the umbilical might be removed from the cave, though... the diver probably wouldn't be able to reel it up as he left, even if it WERE the size of headphone cord... he'd have to have some device or person actively reeling the umb in.
We could take it one step further, and imagine that the umb is not reeled in -- it's left in the cave like gold line. Divers could "clip into it" with quick disconnects. We all understand that QDs are failure prone... but let's assume we have Perfect QD's. Divers carry enough OC gas to get in and get out, and use the umb's as safety devices, and as "time extenders." I understand and agree, though, that no one really wants a big old umbilical routed through pristine cave. Few people realize that exploration, the sense of being the first to ever venture into a new place, is what drives cave divers. Pristine cave is spectacular, and should be preserved at all cost. On the other hand, though, I'm not sure a permament umb, if done right, would be any more intrusive than a gold line, or a cache of stage bottles left by a support team.
Imagine dozens of divers linking into and unlinking from the umbilical as they move through the cave. Each diver carries only enough umbilical to get him from one QD point to the next.
You could even go one step further and give a lead diver a big spool of umbilical, and give each other team member a shorter length that they use to clip into the lead diver. Each team, then, has only one hook into the cave's umb, and there's only one umb going into the cave.
Now, someone's gotta run the compressor up top to keep everyone happy. Each diver would still follow his thirds on his "private" scuba gas -- so even in the event of a catastrophic compressor failure, there would be no loss of life -- the game would just turn back into "old-school" cave diving. Who would pay for the compressor? Who knows? Maybe, if amortized over a large enough number of divers, the compressor's cost might not be an issue.
Pretty crazy. Right?
- Warren
