I now know why one of my posts would look a bit off the subject.
My apologies to George! Looking back at the string it does not explain my deviation form the original question. Every now and then, the system does not post one of my additions to a string and as a result my response may have seamed of track. I also get two of every email posted on P-subs with one subscription address. It must be a server thing.
I suggested the buoy system may be able to have a duel purpose both to navigate and assist rescue.
Also I asked George if the buoys purpose was for general Navigation or something more precise. I believe military subs have a buoy on a winch that can be raised to get a GPS position.
Joe - from my days as a Recreational SCUBA Instructor (and I miss those days) I know exactly what you mean even with GPS. Remember the old days when it was even harder because you lined up a dive site with shore marks and someone would do a bounce with the anchor to make sure you where in the right spot.
I’m interested in this subject not only from a navigational point of view but also being able to locate the sub its self. Is it possible to develop a cost effective and reliable way of finding a P-sub if it goes down? Maybe a mixture of a buoy that would give an approximate location then an Acoustic device to give a precise location once you get close enough. I was also suggesting a Buoy that was released without any rope attached.
From what I can gather P-subers are not using a buddy system like most divers and often dive without escort vessels. Spurdog, Euronaut or vessels of its type are going Bluewater with up to six passengers. It’s worth pursuing if it provided a way of quickly locating and evacuating 6 people? This is even more important if the sub has no diver lockout or scuba equipment on board.
It seems to me the original question was for "precise" underwater navigation. So I suspect Jay is talking about pulse beacons on the seafloor of some type. I will defer to his expertise to elaborate but, I remember reading about an expedition to pacific thermal vents using this method.
I can tell you that as a diver, even with GPS to guide the boat, I have returned to many a same dive site only to have some trouble finding my target again, especially small ones.
My Octopus, as a self reliant vessel, would only leave periscope depth in sound phone contact with a surface escort to keep tabs on traffic, and will navigate in known waters, on compass and depth finder (an acoustic device). Someone with a research or salvage capable craft needs more capability.
It would be interesting to hear from Dan H, as to how he navigates his K350?