Sean,
"two positions in the log, defining the fore and aft extents of the wreck."
Amazing how the simplest of solutions elude a person,...that never occurred to me. I suppose you pick up little tricks like that the more serious your diving becomes. I became certified in 1977 but, never ventured into anything more serious than shallow wrecks and reefs, in S. Florida, you have a lot to see in the no decomp range. Neat trick!
Joe
From: "Sean T. Stevenson" <cast55@telus.net>
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Acoustic Triangulation
Date: Sat, 08 Apr 2006 12:32:19 -0400
>Joe - I used to work for the Canadian Coast Guard, before SA was
>shut off. (SA was turned off in 2001, correct?). Anyway, we would
>do some minor navaids placements from small boats which were not
>equipped with differential receivers, but since GPS was deemed "not
>sufficiently accurate", we had to take horizontal sextant angles off
>of landmarks to fix station, and then stationkeep while the buoy was
>placed. A royal PITA, but good training in seamanship. Even now,
>this method is theoretically more accurate than GPS, but usually not
>worth the hassle except to check position after placement.
>
>For wreck diving, I always thought it would be a good idea to enter
>two positions in the log, defining the fore and aft extents of the
>wreck. This way, if you anchor instead of live boating, regardless
>of the hook position you have a reference for the divers which
>hopefully will minimize any required search.
>
>-Sean
>
>
>Joseph Perkel wrote:
>
>>Stephen,
>>
>>" Remember the old days when it was even harder because you lined
>>up a dive site with shore marks"
>>
>>I still would still rely on this even after the end of SA
>>(selective availability) of the GPS system to get to a spot quick,
>>fine tune with the GPS, and then spot the wreck on the sounder. My
>>problem was always anchor placement, and then how far off the rode
>>placed the boat and in what direction. It never occurred to me to
>>learn how to use a grapple...silly really.
>>
>>Joe
>>
>
>
>
>
>
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