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Jon Guizar <jeg154@ps*.ed*> writes: > I haven't seen any of those dudes from MIB yet but I was just concerned = > with the ability to find your way out if the line WAS compromised. Not = > addressing the possibilities of how it got that way, just that there = > you are under the ice and your line is broken. How would you rescue = > yourself? 1) Care that this doesn't happen in the first place. Heavy line is used, one end is shackled to the diver's harness, then a loop is tied a few feet along for the diver to hold to give signals, then the tender holds the line above the hole, and then the other end is anchored to the ice on the surface. You'd need a double failure (mechanical anchor and human letting go) to lose either end, and chances of the line being abraded in the middle are minimal. It does run around the "corner" at the bottom of the ice at the hole, but this is generally fairly smooth, and bouyant line isn't going to readily get caught on anything on the bottom. 2) Before the dive, carve a "wagon wheel" on the surface by pushing a shovel over the ice and clearing surface snow. From below, it looks like fluorescent tubes in the ice. Use one of the diver lines to help do the main circle at that radius, then do several "spokes" inward to the hole. "Barbs" partway along act as arrows to indicate direction. 3) If, heaven forbid, you do find yourself off the line and don't see the "wagon wheel", ascend to just under the ice. The safety diver will do a circular sweep with his longer line, and being bouyant it'll come to you. Also, your air consumption while you're waiting is minimal shallow. Note that if (1) is done right, chances of needing the contingency plans drops to virtually zero. Also, we normally run two divers each on his/her own line (dive plan is that one should stay "clockwise" of the other to minimize line crossing), so even if a line did fail, simply being with your buddy gets you back. I should, however, warn about a charlie foxtrot some folks did some years ago. Two divers got under the ice and found they had attached both ends of the same rope to themselves, and the middle had gotten away from their (untrained) girlfriends who were tending line for them. Both ends of the second line were anchored to the ice. Fortunately, they knew the dive site well enough from diving in the summer that they were able to navigate back to the hole based on bottom topology. The kicker was that their safety diver had figured he'd be bored sitting up top, so he was swimming with them, his line was properly secured, and they never thought to simply follow it back to the hole. Needless to say, we always lay out our lines each separate from the others and make sure one end of each is anchored before anybody gets ready to go in the water. All of the above is covered in any good ice diving course, and I hope nobody is considering a good hashing-out of issues on the lists to be a substitute for good training. I should add, for any cavers who remember their Accident Analysis, that the reasons people get killed are basically the same. Not being trained tops the list, and failing to have a continuous line is second. You're rarely far enough from the hole for air or depth to be an issue (although if you're in with a single [not I, thanks] and start freeflowing, you do want your tender to start pulling as soon as you give the haul-me-in signal), and any daylight dive under the ice has lots of light. In place of AA's "Depth" item, though, the cold can get so numbing that you'd be of more use at 180 on air, and this has to take a similar role in winter diving accidents. If you get too chilled, get out of the water and look into better thermal protection or shorter dives. -- Anthony DeBoer <adb@on*.ca*> -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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