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Wendel, In the UK, due to tides, it is very rare to find dive boats anchoring to wrecks. The normal way to dive here is for the wreck to be 'shot' ~ this is a 56lb weight on the correct length of rope with a large buoy at the top. There is usually a smaller one attached about 2m down from the top. This allows the tide to be gauged as we can only dive when the tide is slack. All our dive planning and departure times etc are totally governed by this tide window. Some skippers use a grapnel type shot, which is basically a 1/2m box section filled with lead and tines welded on the sides so it grips the wreck better. To shot a wreck, we would locate it using GPS and a good sounder. We would then drive up tide and past the wreck & drop the shot. This would ( hopefully ) land on the uptide end of the wreck, with the shot line going over the wreck, so the divers always find the wreck. Note: our visibility is normally about 5m with >10m only at exceptional times. At no time would we ever send down a diver to tie in to a wreck ~ our Health and Safety Executive would have our guts for garters. The skill of the skipper is key to being able to do this & generally most UK skippers hit the wreck first time & this is confirmed by 'seeing' the shot line on the echo sounder. Submarines are sometimes slippery customers, particularly if they are aligned bow to stern with the tide, but never the less any decent skipper can normally hit even the smallest of targets. One skipper down here is capable of 'shotting' wrecks that are in 150m of water in a 5kn tide. When the divers ( and the tide ) are ready, the boat would approach and go past the buoy very slightly ( into tide ) & the divers would jump off the boat ( usually a horn is blown ). As there is fractions of tide left, the divers drift gently down onto to the buoy & after exchanging signals, decend. This is repeated for all divers, with a gap of about 3mins to allow each team of divers to decend. The divers locate the wreck by following the shotline down. It would be impossible and dangerous to attempt to find the wreck without a fixed datum. Our visibility & tide preclude a diver finding the wreck by either just dropping down or even scootering down. The boat then protects the area from shipping ( flying the international 'divers down' 'A' flag ) The boat then protects the SMBs as they are launched by each diver for deco. At the end of the dive, the shot is recovered using a pot winch. Occasionally the weight is lost, due to it becoming embedded into the wreck, but the winch is strong enough to break the line, so the rope is re-used. hope this helps you get an appreciation of how we do things on the other side of the pond. The deco is done drifting as described previously and is as relaxed and comfortable as we can possibly make it. best, Dave At 07:43 AM 7/29/02 -0700, wendell grogan wrote: >Just before this latest tiff started, I had been >getting a lot of very interesting information (off >list) on how things are done in the British Isles. >They do this (drift deco after dive bombing the wreck) >as a matter of routine, but there is quite a bit to >consider and a number of new skills to be practiced >for this to come out right. >I was also thinking about the advantages last weekend >while doing my 20 foot stop along with what seemed >like a cast of thousands, the boat bucking in rollers >perpendicular to the slight current and helping out my >buddy with a leaking back up reg hose... >Basic Anglo-Saxon words regarding various bodily >functions kept going through my mind, but the >conclusion seems to be that we should start doing this >here in the North Atlantic US. >The problems are inertia and a lack of >experience/training that would make it a matter of >routine for most if not all dives. Also, since the >thing that drives the industry is people who are >either taking or just finishing AOW going on shallow >wreck dives, finding a boat operator who wants to run >the training dives on what would normally be their >milk run wrecks, is going to be tough. >Wendell > >--- Jim Cobb <cobber@ci*.co*> wrote: > > This leads back to the basic question: What do you > > require to be on your > > diveboat before you go out on it? George knows this > > situation with > > chaseboats and his solution, which costs the dive > > operations nothing but > > some fuel and inconvinence, is to not anchor to a > > wreck during a dive. > > Problem solved. No chaseboat needed, no deployment > > issues. > > > > Jim > > > > > >__________________________________________________ >Do You Yahoo!? >Yahoo! Health - Feel better, live better >http://health.yahoo.com >-- >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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