"The main disadvantage of a hardwire system is diving in a snag prone environment. The wireless system will allow a diver to swim free through pilings, trees and other hazards. This is something that has to be thought through from a safety standpoint. Determine if this is a feasable method of diving for your environment and teams level of training. Also take into consideration the drag of the ComRope. There can be a lot of drag with a 150' piece of rope."

Our procedures say that if there are enough snags for a line to become tangled in then the last thing a diver wants to do is to dive without a tether. That is said with many exclamation points. If there are lots of snags then change the type of pattern to decrease the number of snags. Remember everyone that if the line can become snagged so can the diver. If there is low or no visibility then without direct line access to the tender, there is not way to gaurantee that the backup or 90% ready diver can find and then reach that diver in a timely manner. Descending on a diver's bubbles in low/zero visibility is make believe - especially in moving water - and even if that did work, then it still would not address the situation of a diver no longer breathing. So, as John said, determine a feasable method for you. Feasable means you have a practiced, proven contingency plan - and if you are not fully sure you can get your diver out if it goes bad, then do not do it.

The OTS comm line is a good diameter. Our max recommended distance out for that line is 125 feet, with a possible 25 foot extension depending on conditions and the backup divers. (remember, the backup divers should be equal to or stronger than the primary diver). With a proper harness and good procedures a line can be held taught without much effort up to 125 feet. It takes a little more effort to keep a 150 foot line tight, but not really much more. The key is for the diver to be at a 45 degree angle away from the tender: put the diver perpendicular to the line, and then turn the diver 45 more degrees away from the tender. That is the only position that will work to keep the line taut with little effort for any reasonable amount of time. If you are perpendicular to the line or if you are holding a loop in the line - how can the line be kept really taut? How do you move sideways to keep the line taut? If there is slack between you and your handloop, you wont have a taut line without lots of arm effort.

If you can't picture what we're talking about, do it on land first. Hook up to the line with a tender holding the other end. Lay on the ground with your body perpendicular to the line. In that position, you will have to move sideways to move away from the tender. Hence you have to move sideways to keep the line taut. You can't keep the line taut by kicking because in a perpendicular position kicking will only move you forward, not against the line. If you try to do it by pushing off the bottom with your hands then the search is screwed up. Now lay on the ground and swing 45 degrees away from your tender so that your tender is looking at your right or left shoulder blade. See that you can swim against the line and progress forward simultaneously with little effort - all from the legs keeping both your hands free for searching.

This does require you to have a good harness though with a tether point at the solar plexus. The harness tether point needs to stay in one place regardless of how hard you pull in any position. Too many harnesses we see allow the tether point to move even as far up as under the arm pit when a good taut line is held. - hence some teams go for the hand loop in the line to prevent that from happening, and hence there goes the taut line. Many teams are saying, hey, we do have a taut line and we do have a hand loop. If you are saying that I ask you is your line pre-marked every five feet and is your backup tender drawing your diver's pattern while checking that if the diver is supposed to be at 37 and 1/2 feet out on this sweep that the diver really is at 37.5 feet out. If not, you may find that your diver is not exactly where you think the diver is. If you are tying knots in the line every ten feet, the likelihood of an accurate pattern is slim to none (aside from creating other problems with the knots). If your line is pre-marked, but only at 10 foot increments, the pattern could easily be off anywhere from 6 inches to 3 feet on any one or more sweeps. Add up that inaccuracy after 5 sweeps and Houston, we have a big search problem. Seriously, try it out on the floor, and then in the water and see what happens before you say that we're wrong. Try things hands on before making absolute opinions.

Chuck, you also brought up an interesting topic: being spooked, the heebeejeebees that I mentioned in an earlier posting. You posted that you shouldn't dive if you are spooked. True, you should not dive if you start out spooked, but I ask the group, is there anyone here who can honestly say that they have never been spooked even for a minute during a low vis/blackwater diver - particularly when something bumps into you (like an eel) that you can't see or you bump into something that you also can't see? I believe that can happen to anyone, even with 20 years of diving experience. If we are prepared for such occurences then we can manage them. For me, if I denied them, or if I told my students that they should never feel spooked ever, then I think we wont be as prepared for those feelings. Yes, Chuck, training, training is the key. There is a big difference between being spooked and feeling nervous because you do not feel comfortable about making the dive. If the latter exists then do not dive or abort the dive. My definition of spooked is an irrational feeling that has nothing to do with the safety of the dive. Spooked is not knowing what is causing you to feel creepy. Does that make sense? You know the back up and 90% are ready to aid you should you need them. You know the back up tender is monitoring your bubbles and integrating that with your SAC rate to make sure you have plenty of air, you know the back up tender is drawing your every location on the profile map. You know you have a full pony bottle and will be told to surface before your main bottle reaches 1000 psi. You know you have 3 cutting tools in the golden triangle area that you have practiced with. Yet, all of a sudden you feel a shiver.

Okay, so now we have several good lines of discussion (solo vs multidiver patterns, untethered diving in entanglement areas, body positioning and keeping the line taut, harness design, boat race rescue operations, being spooked, distance out.....) to think about and post. Looking forward to hearing from lots of you.

On a completely different note, please, please, please when you send a posting that is a replly, erase everything before you start writing. If you don't erase what was below then it gets really messy for people who want to print it out, and it makes the digest really really messy. So please just start with a clean slate and then reply. If you need to comment on specific sentences simply copy those sentences and incorporate them into your posting. Thanks!

Cheers,
Andrea

Andrea Zaferes
Lifeguard Systems & RIPTIDE
www.teamlgs.com www.rip-tide.org
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