[PSUBS-MAILIST] auto pilot

Mon Mar 6 00:35:33 EST 2017

Hank,

Sure sounds like you have a lot of redundancy. I think the thought of not
being able to successfully retrieve your sub on the initial deep unmanned
dive has got to go threw everyone's mind while doing it as it is a major
loss of time and money hanging on the end of a rope that could be gone in a
flash.
I have thought a lot about it myself and plan on using one of my 5 ton lift
bags attached just above the sub with the end of a dive umbilical lashed
inside of it and tethered to the load line every 30' or so and attached to
an air source in the boat as a last ditch effort. The only major concern is
that it would be an uncontrolled accent and once it starts up, she will
build up some speed and the bag may come out of the water and burp the air
sending her back down.
Another thing I thought of was putting two video cameras inside, one facing
forward and one facing aft so if something started to leak, you would see
it and be able to abort right away but then you would need a penitrator to
pass the power outside the sub and in my case, over 600' of cable for it.

Rick

On Sun, Mar 5, 2017 at 3:32 PM, hank pronk via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Al,
> Yikes, never thought of that, and I know Gamma rotates when descending.
> Hank
>
>
> On Sunday, March 5, 2017 6:21 PM, Al Secor via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>
> Hank,
>
> When we did the drop test on Persistence, we had a tether rope and another
> rope to release a drop weight so the sub return to the
> surface.  When the sub descended, it rotated on the way down causing the
> two ropes to become intertwined.  It was impossible to
> pull the release rope for the drop weight.  Keep this in mind with the
> clothesline effect idea...
>
> Al Secor
>
>
> ------------------------------
> *From:* hank pronk via Personal_Submersibles <personal_submersibles at psubs.
> org>
> *To:* Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> *Sent:* Sunday, March 5, 2017 6:14 PM
> *Subject:* Re: [PSUBS-MAILIST] auto pilot
>
> Hi Steve,
> Gamma has battery boxes in the bottom of the hull that conveniently create
> a water trap at the front and back of the hull.  Less than a gallon of
> water will trip the float switch.  The air supply actually comes from my
> external 122 cubic foot tank.   The other tanks I was researching are for
> Elementary 3000.  Unfortunately  Slocan lake is very steep on the sides, so
> I have to test in much deeper water with the sub suspended.  There are also
> sunken logs all over the lake, so I want to stay off the bottom.
> Funny I was thinking today, I need to buy another roll of rope so I can
> have a clothesline effect.  The rope will loop through the lifting eye and
> back to the surface.  In a failure, I can pull a small cable down to the
> sub to hook it up, or get another sub out to connect it.  Actually you have
> an idea here, it could have a cable held up with trawl floats that can be
> snagged easily with a grapple hook.
> Hank
>
>
> On Sunday, March 5, 2017 3:42 PM, Stephen Fordyce via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Hi Hank,
> A pretty basic thing, but do you have enough air supply?  Ie. perhaps you
> will need quite a bit of water leaking in to actuate the flow switches.
> Which needs quite a bit of buoyancy, and since you are at test depth you
> have a whole lot of extra ambient pressure to compensate for. Ie.
> your 10.7cu ft cylinder at 1500PSI will hold air to displace about 1000cu
> ft on the surface, but only 35cu ft at 300m depth.  If that's what you're
> using, I think you will be ok ;).
>
> Another consideration is that for the sake of a few minutes extra before
> the test, it may be worth a couple of minor considerations in case the
> auto-surfacing method fails.  (ie. find a spot in the lake where there is a
> flat bottom at desired depth, leave a lifting ring attached/sticking up so
> that a cable could later be attached to it for lifting a fully flooded sub,
> etc.).
>
> Cheers,
> Steve
>
> On Sun, Mar 5, 2017 at 10:27 PM, hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Alan,
> Yes I have opted to exhaust my air supply into the MBT's, if I put a
> timer on the solenoid valves to close them, it may not lift if the sub is
> in a snag of some sort.  I want full lifting power.  The solenoid valves
> will be piped into the existing air feed for the MBT needle valves.  I will
> have the needle valves set to feed the air slowly.  I expect Gamma to be on
> the surface before the air is spent.  I am attaching a 5\16 nylon rope to
> the sub and lowering it 5 lbs heavy, so I could haul it up if I had to.  If
> my timer fails and the sub does not surface, I can also simply lower the
> sub another 50 feet or so and the outside  pressure valve will send power
> to the  solenoid valves.
> Hank
>
>
> On Saturday, March 4, 2017 10:49 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.
> org <personal_submersibles at psubs.org>> wrote:
>
>
> Hank,
> when the valve opens, is it going to stay open & continually send air
> in to the ballast tanks? Also you mention an external pressure sensor
> to avoid going too deep; are you sending it down on a rope or autonomously.
> Alan
>
> Sent from my iPad
>
> On 5/03/2017, at 2:49 PM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.
> org <personal_submersibles at psubs.org>> wrote:
>
> Hi All,
> I am in the middle of building a remote surfacing system for my subs since
> I seem to be to cheap to go to a pressure chamber.  My system operates from
> a dual industrial timer that powers two solenoid valves, one is redundant.
> The solenoid valves take regulated air to operate an air cylinder that
> actuates a 2,500psi ball valve.  The system also incorporates two float
> switches, one fore and one aft in case water gets in before the one hr test
> is complete.  There is also a internal pressure sensor in case there is an
> air leak, the sub will surface.  There is also an external pressure sensor
> that will prevent the sub diving past the desired pressure test depth.
> Have I missed anything?
> Hank
>
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