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Re: [PSUBS-MAILIST] Safety Hook

Hi Alan
Making a standard lift bag is simple and quite cheap but,to manufacture a strong pillow bag with a pressure relief valve....... couldn't be that hard ,just think how flat it could be sucked and you could catch a tan on it while you waited for rescue.Tractor tires? NZ is just one big farm.
Glen
----- Original Message -----
From: Alan James
Sent: Tuesday, August 31, 2010 11:08 AM
Subject: Re: [PSUBS-MAILIST] Safety Hook

Hi Glen,
what about an enclosed bag with pressure relief valves on the bottom?
As you'll know the last 33 ft the bag will double in size & lifting ability,
so if you put it on the surface you'll get the maximum out of the air you
put in it. You could modify a tractor tire; that would have the potential to
expand if necessary & with a base on it, it would be an inflatable boat
waiting for you if you needed to escape.
Just brain storming here.
The Aussies might dump their coach, he's a Kiwi.
Alan
----- Original Message -----
From: glen brown
Sent: Tuesday, August 31, 2010 8:35 PM
Subject: Re: [PSUBS-MAILIST] Safety Hook

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 James
Sent: Monday, August 30, 2010 10:40 PM
Subject: Re: [PSUBS-MAILIST] Safety Hook

Hi Glen,
You could just let the lift bag spool until it stopped & then wind it
back down. Put in just enough air to have it fully inflated by the time
it reached the surface. A colorful 1 ton lift bag would certainly stand
out more than a small buoy & possibly take up a similar space when
deflated.It was noted that your lift bag idea was ratified by Phil.
Regards Alan
----- Original Message -----
From: glen brown
Sent: Tuesday, August 31, 2010 2:09 AM
Subject: Re: [PSUBS-MAILIST] Safety Hook

If 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 ect 
Glen
----- Original Message -----
Sent: Monday, August 30, 2010 11:47 AM
Subject: Re: [PSUBS-MAILIST] Safety Hook

To 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

Frank
Dont 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 James
Sent: Monday, August 30, 2010 12:05 AM
Subject: Re: [PSUBS-MAILIST] Safety Hook

Hi Frank, Looks good.
You could spring load your device by putting a rubber O ring in a grove round
the outside of the prongs, if it were necessary.
The lifting eye would be vertical when the emergency line was tightened
providing 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 no
success so far. It's a big world, there's bound to be something out there.
Alan
----- Original Message -----
Sent: Monday, August 30, 2010 2:33 AM
Subject: Re: [PSUBS-MAILIST] Safety Hook

Here'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.