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Dean,
I really have no use for 600 feet of line other then to test the sub so I
didn't want to invest a bundle in expensive line for only one use. The
stretch wasn't a problem other then it was difficult to say exactly what was
happening on the other end. I know we didn't stretch it 1/3 by hand but it
did stretch. My release line was also nylon but braded string rather
then actual rope. I sure stretched it before giving up and heaving the sub
up hand over hand.
Dan H.
----- Original Message -----
Sent: Sunday, February 08, 2009 12:36
PM
Subject: Re: [PSUBS-MAILIST] safety
chain
Dan look at it this way you will prevent all reading this the
pain of your adventure.
Yes a nylon rope will stretch a 1/3 it's length. Nice if you are
bunggy jumpin but not
haulin up from the deep.
I am surprised of the pull pin not releasing. I am guessing that
was nylon
also.
For sure I will remember that when it is time
for my dunk test. I will have a 3 to 5 ton winch on board my
surface craft with plenty of cable.
This was to be added anyway, so might as well be done with it and
make things easier for
testing. Now that I am thinking on it a 5 ton at
least.
And Alec if you are monitoring as before I will be glad to take
you and your 250 out and
get it wet when you are ready.
Dean
In a message dated 2/8/2009 9:38:20 A.M. Central Standard Time,
Jumachine@comcast.net writes:
Dean,
It was a windy day when we did the unmanned deep water test on my
sub. First off, the wind kept us drifting down the lake. Second,
the water was choppy from the wind and the sub was on a nylon line. At
540 ft it had some stretch to it. These factors made us need to keep
an even pull upward, no matter if the sub was moving or not. One
person could pull on the line but it took two to make progress because of
the elastic nature of the pull. We would both pull, then one hold and
the other get a grip farther down then repeat. With the elastic line
we couldn't even tell if we were actually hauling sub or just stretching
line. When we got fifty feet or so pulled up we figured we must be
moving the sub. It's difficult to estimate resistance. We were
fighting so many forces that also includes inertia of the moving sub with
out tugs on the line, the weight we had to over come and the water flowing
around the hull.
The original plan was, the sub was to be weighted 30 pounds heavy with
expendable drop weights that were to be released by puling on a second
smaller line. That was attached to a release pin on top of the
sub. I figured, even if the lines wrapped around a bit, one would
still slide by the other. That didn't happen!
We had to hand haul up to about half way, then unwrap three twists in
the line. After that we pulled the pin and waited till the sub
surfaced. Let me tell you.... It was a great sight to see that
yellow hatch break the surface!
If I was to do it again, I'd use a electric weight release and send
down two wires with the nylon hauling line. That way wrapped wires and
line wouldn't be a problem. Or have a winch on the surface boat
capable of 600 feet of line.
Dan H
----- Original Message -----
Sent: Saturday, February 07, 2009
9:28 AM
Subject: Re: [PSUBS-MAILIST] safety
chain
Dan good thought on a com wire. It sure would be
better.
Do you have an estimate of how much water resistance you
encountered.
I guess not a lot if you were able to hand haul it
up.
Was that the plan to begin with or a SNAFU?
This spring I will be installing a winch on my surface
boat.
Dean
In a message dated 2/6/2009 8:57:27 P.M. Central Standard Time,
Jumachine@comcast.net writes:
Dean, Frank
I don't have a float system on my sub but have given one some
thought. It would be pretty difficult to have a cable on the sub
capable of lifting the subs weight flooded. Mine was just about 30
pounds negative when we tested it on a line and had to hand pull it
up from 540 feet. Al Secore probably still is walking bent
over. Thirty pounds heavy, in rough water, with the resistance of
the water flowing around the sub as it rises is a lot more then thirty
pounds hanging on a hook in the shop. Any cable would have to
have a reasonable safety factor for rough conditions.
Also, having a way to communicate with the trapped sub would be
nice for the folks on both ends. I was thinking of making
my float pull up a wire pair from a spool on the sub. It
could be used with equipment you surface crew can carry for emergency
communications and also serve as a guide to send help down to you.
Your surface support crew can carry a latch mechanism that is
designed to mate with a mushroom shaped pin on top of your sub. If
the emergency alert line emanates from the top of the mushroom, your
latch mechanism can be threaded on the wire at the surface and slide
down till it hits the top of the sub and latches. Of course you
first need to attach a strong cable to the latch before you let it
down. The big question is, will there be a winch heavy enough and
a cable long enough available but you need the winch no matter how you
do it.
We used to use a similar system to retrieve rock core samples from
a drill tube instead of pulling up the entire drill string. The
latch was sent down the drill pipe till it hit a mushroom pin on top of
the core barrel. It would catch and you started hauling it up.
I like the idea of wires to communicate through.
Dan H.
----- Original Message -----
Sent: Thursday, February 05, 2009
2:36 PM
Subject: Re: [PSUBS-MAILIST]
safety chain
Hi Dean. I think an 1/8 inch is way too small. We discussed this
last year and it's a good idea to have the ability to pull the sub up,
but carrying a spool/cable assembly on board will require a pretty
heavy set-up.
One idea tossed around back then was a
float and cable like you had planned, but the cable is used as
a guide for lowering a "clamp" that would be capable of
attaching to the sub to pull it up. That way the heavy "clamp" is
carried on board the surface craft where it's not exposed to sea
water, doesn't add any weight to the top of the sub, and can have a
thick cable strong enough to pull the sub free from mud or minor
entanglement. Just lifting the sub alone may not be enough if it's in
the mud or hung up on something.
It should be pretty easy to fabricate some
type of "hook and latch " device that the clamp can drop onto ( guided
by the float/cable ) and then be able to pull really hard if the sub
got stuck. An 1/8th inch cable would then be enough if used as a
guide. Frank D.
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