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> > > What do you do if the line catches again on the ground ? > > > > Chances are it won't hang anything significant on a sandy bottom (which is > > the case for most deep sites). The force in a high current can be quite high > > and will pull loose most obstructions if it does. > > > Well you may have mostly sandy bottoms over there. > I once saw a small chain get snagged into a little gap on a little rock. > It's still there. A commercial diver saw this and said,..blast the > rock... You adapt your methods to the environment. If the bottom is rock or environmentally sensitive then you may shorten the line so it is not dragging. No big deal. > > So if you take a snagged line into account, you also do for an ascent in > the current as opposed to drifting. Only then you are obliged to leave > the downline attached. The ascent is still a drift because the divers switch to liftbags they carry and continue. The boat operator knows the snag has occurred by monitoring the surface floats. He expects to see the liftbags. The deco proceeds as planned. This is not rocket science. > > When I understand correctly, your method is similar to ascending from a > shotweight line, which is also released at the end of the dive from the > wreck, but heavier, and will provide less drifting Not necessarily because the idea of a slightly weighted end is to allow the upline to drift along with the current and not offer much resistance. The concepts are different. > > Only a well placed shotweight will sit in the wreck while divers drift > into it from upstream, whereas in your example it depends on the driver > who leads the line. So if they miss, all miss. > > Matthias > If they all miss then they are functioning as a team. The diver who leads the drop also has the team with him (remember buoyancy control). The reality is in high current you may be able to snag a small wreck (e.g 75' upside down fiberglass trawler) at 400ft from the surface and then you would have a fixed line to it, but I doubt it. 'But you aren't going to pull the team down the line to the wreck anyways - it would be foolish. Second, even with a fixed line in place, the divers will still have to drop ahead of the wreck and drift into it (no different than carrying the upline end). If you are going to miss it carrying the line end, then you will miss it with a fixed line as well. Another point with carrying the line end, is the dive team is connected to the surface via the line and the floats. The boat operator knows where you are. Not the case when trying to drift into a wreck without carrying the line end. If you miss the wreck and are carrying the line end, you now have an ascent line and the boat knows where you are. You can waste your time thinking you are improving the situation by dragging to hook a wreck; or you can drop on the wreck, do the dive, and be back on shore in time for the afternoon matinee. There's no need to make this difficult (think simplicity and who should be in control of the event). - Doug ----------------------------------- > Of course if it is another > > wreck then consider yourself fortunate and deal with it. That's why you have > > liftbags and a captain with a clue. The captain will know the upline has > > snagged and will see the liftbag(s). A no-brainer. > > > > > If I understand correctly, this "one diver with the chain end", will he > > > have a buddy ? > > > > Definitely. > > > > > Does he hold to the end, or just follow ? In case b) > > > everyone can follow. In case a ) he is obviously more negtive than than > > > the rest. > > > > Holds the end. The idea is to tie the line end into the wreck. Hey the chain > > ain't a ton as it only provides something that can be attached to a wreck > > and not be frayed, and will give a little deadweight on an upline! Sure he > > will be more negative but a properly weighted diver will have sufficient > > reserve buoyancy. If the diver is properly weighted he and everyone in the > > team will have no problems staying together. Anyways the trick in a high > > current is to drop relatively fast so you can drift into the wreck and not > > miss it. If you fart around you will miss it every time. 'And you may > > anyways on deep drops as the bottom currents can be significantly different > > than the top at least in near-coastal Florida (e.g Ekman motion from the > > Coriolis force, fetch, duration, upwelling, longshore drift, etc.). > > > > >What, if he has trouble equalizing ? > > > > Then he's a wuss and deserves to be picked up by the boat and miss the dive! > > Think, a properly weighted diver will be in control. > > > > > Maybe I did not understand the full context, so please feel deliberate > > > to explain a bit more. > > > regards > > > Matthias > > > > Take care, > > Doug > > > > > > > > > > > > > > Just for thought: > > > > > Upline with sufficient but not exceessive scope, redundant surface > > > > > floats, and bottom chain with snap/hook. Down rig with divers is > > > > > dropped ahead of wreck to drift into wreck (one diver in team drops > > > > > with the chain end). On end of dive last divers detach chain from > > > > > wreck and toss into sand. Proceed up line. Now the line is drifting > > > > > with the current with a slight bottom drag from the chain. No flag > > > > > flying. No issues. Relaxing. The boat is always free to maneuver. If > > > > > too crowded on line, you can hover alongside or pop a lift bag > > > > > nearby. Will still drift the same as main upline with a slight > > > > > backpeddle to compensate for chain drag on main upline. The captain > > > > > on the boat knows where everyone is; can drop a safety diver on you > > > > > if appropriate and recover used stages. Its a piece of cake and > > > > > works well in raging currents like we can have in the gulf stream > > > > > (and with close to shore shipping as well). A slight mod on deep > > > > > stuff (350+) though, and you need a captain with a clue. > > > > > -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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