Hi Alan
In experience as a commercial diver using '
unmaned 'standard lift bags, when they hit the surface they do so
like a rocket loose there form and sometimes the item you where lifting comes
hurtling back in your direction.This is the reason for a controlled ascend and
not letting the bag exit the water until its been established that self rescue
is not possible .With no weight it could
allso be blown over by the wind and loose form iniatialy when it reaches
the surface,but with the right construction and say a 5kg lead ball (like the
ones they use on down riggers)attached to the bottom, bright orange with a
couple of reflective flashes and instructions attached to it .Once let to the
surface it would be seen for miles.
Glen
----- Original Message -----From: Alan JamesSent: Monday, August 30, 2010 10:40 PMSubject: Re: [PSUBS-MAILIST] Safety HookHi Glen,You could just let the lift bag spool until it stopped & then wind itback down. Put in just enough air to have it fully inflated by the timeit reached the surface. A colorful 1 ton lift bag would certainly standout more than a small buoy & possibly take up a similar space whendeflated.It was noted that your lift bag idea was ratified by Phil.Regards Alan----- Original Message -----From: glen brownSent: Tuesday, August 31, 2010 2:09 AMSubject: Re: [PSUBS-MAILIST] Safety HookIf a hand operated winch spool filled with Spectra, marked for different depths and controllable feed by pilot ,attached to the end is lift bag ,not much air would be needed to fill bag as the pilot could place the lift bag closer to surface, once free from bottom pilot could winch himself to surface by hand.If he is unable to free himself from bottom he can release the bag all the way to surface to act as marker stress Buoy ectGlen----- Original Message -----From: vbra676539@aol.comSent: Monday, August 30, 2010 11:47 AMSubject: Re: [PSUBS-MAILIST] Safety HookTo offset the catenary, HBOI did a series of tests running upstream slightly. This did not straighten the curve, but rather moved it to a more vertical position at the sub and tensioned the whole length so that the rescue device had a better chance to get down. It worked.Phil's suggestion of carrying enough Spectra to provide both a marker and a lift line is certainly worth our attention. That stuff (Spectra) is fearsome strong, and would do away with almost all of this extra hardware. The big buoy or lift bag would provide a further lift ability and if necessary could be released to the surface. Wrap the Spectra around a cat head and haul away.Vance
-----Original Message-----
From: glen brown <gbrown091@gmail.com>
To: personal_submersibles@psubs.org
Sent: Mon, Aug 30, 2010 3:58 am
Subject: Re: [PSUBS-MAILIST] Safety Hook
FrankDont forget to take in consideration the bow effect(in deeper water) that any current will have on the rescue cable . The hook will have to be very heavy otherwise it will be useless in stronger current.Glen----- Original Message -----From: Alan JamesSent: Monday, August 30, 2010 12:05 AMSubject: Re: [PSUBS-MAILIST] Safety HookHi Frank, Looks good.You could spring load your device by putting a rubber O ring in a grove roundthe outside of the prongs, if it were necessary.The lifting eye would be vertical when the emergency line was tightenedproviding the line from the drum was above the lifting eye.I googled round a bit trying to find something "off the shelf" that would work but nosuccess so far. It's a big world, there's bound to be something out there.Alan----- Original Message -----From: ShellyDalg@aol.comSent: Monday, August 30, 2010 2:33 AMSubject: Re: [PSUBS-MAILIST] Safety HookHere's a little sketch on an idea I had for a simple hook to follow the buoy line down. It's much like Phil's idea, but I'm using the lifting eyes I have welded to my sub. With a "three prong" approach, ONE of those damn things ought to grab.It would operate like a fish hook where the support crew would keep "jigging" the hook up and down until it grabbed.Any comments ?Frank D.
