[PSUBS-MAILIST] Depth tests at Seneca

Tue Aug 31 18:13:17 EDT 2021

Well done guys!  You are the envy of us couch potatoes.
All the best 
Hugh

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Today's Topics:

   1. Re: Depth tests at Seneca (via Personal_Submersibles)
   2. Re: Depth tests at Seneca (Cliff Redus via Personal_Submersibles)

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Message: 1
Date: Tue, 31 Aug 2021 18:56:06 +0000 (UTC)
From: via Personal_Submersibles <personal_submersibles at psubs.org>
To: "personal_submersibles at psubs.org"
	<personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] Depth tests at Seneca
Message-ID: <323004978.703150.1630436166186 at mail.yahoo.com>
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Very cool. Way to go, Trevor!Vance

-----Original Message-----
From: Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org>
Sent: Tue, Aug 31, 2021 10:45 am
Subject: Re: [PSUBS-MAILIST] Depth tests at Seneca

A really nice thing was the diving the next day. In particular, that my
teenage son got to dive in a sub for the first time. The focus was not on
video, but here's a short 3 minute one that was an accidental byproduct.

https://vimeo.com/594808783

On Tue, Aug 31, 2021 at 10:24 AM James Frankland via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:

Hi Alec
Saw some pics on facebook.? Looks like a great test day, even with the
flooded pod.? Glad it all worked out.??
On Tue, 31 Aug 2021 at 00:17, Alec Smyth via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:

Another fun thing was that Cliff got to take a dive in Shackleton. Maybe he
can give us a review, a la Road and Track or such!
:)
On Mon, Aug 30, 2021 at 5:38 PM Alan James via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:

 Great report thanks Alec.?Glad you survived the battery pod flooding, that
could have been expensive.?I know GL had a similar rule to what you are
saying ABS has, but it was that any compartment (apart from the pressure
Hull) that can flood has to be able to be mitigated by drop weights etc.
Can't remember the exact wording.?Good to hear & learn from the fails.Thats
a pretty good check list for testing;it should be up on the Psubs site
somewhere.?Alan?
    On Tuesday, August 31, 2021, 09:18:56 AM GMT+12, Alec Smyth via
Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 Hi Friends,
Steve McQueen and I just depth tested our subs in Seneca Lake, and I thought
I'd send a little writeup. But first, many thanks to Cliff Redus and Dan
Lance for crewing!?
We prepared our subs by installing temporary MBT plumbing outside, with
valves that could be operated by swimmers. The subs were to be sent down on
an anchor line, and would blow tanks an hour later automatically. The
"auto-pilot" that blows ballast uses a timer, but will also blow ballast
ahead of time if a water detector senses a leak.?
Both tests were successful, but both were also a little too exciting.?
In my case, Shackleton developed a 45 degree list during the tow out to the
test site. I was pretty certain it was a flooded battery pod, and could see
the cabin was dry by looking into the bow dome, so decided to go ahead and
send her down because, even though a flooded pod is a lot of extra weight,
the pods are sized not to result in negative buoyancy when flooded. That is
an ABS rule. The sub did indeed come back up after an hour, with the cabin
still dry.?
Once back on land, we found the source of the battery pod leak had been
owner stupidity (surprise!!!) I normally open the pods for charging, but in
this instance had thought it unnecessary because the charging was just a
really small top-up. Wrong... battery off-gassing had dislodged a pod cap
O-ring. On top of that, my pods have over-pressure valves that would have
avoided the issue, except that I'd bolted them as an extra security measure
to prevent a leak path on the test. After all, I don't think anyone else has
put OP valves on their pods so reached the conclusion they weren't
necessary. Well, lessons learned. Moving forward, caps will be coming off
during any charging, and the OP valves will go back into operation too (e.g.
to prevent against heat expansion.) The good news is that the flood does not
appear to have affected the batteries, which are AGMs. We dove the sub the
next day. All worked perfectly and the battery voltage had not decreased in
the slightest.
Steve's sub, The Great Escape, had a minor issue involving the temporary MBT
plumbing. Steve had plumbed both MBTs together, to a T, and put a ball valve
on that. What happened was a siphon effect between the two tanks. Whichever
MBT was slightly lower in the water would transfer air to the higher one,
from which it would escape. Steve redid the temporary plumbing, putting a
separate ball valve on each tank, and the issue was fixed. His test went
well, except he was conservative turning the knob on the timer, so the
autopilot went off about 20 minutes later than planned - and he probably
aged 20 years in those 20 minutes.?
Seneca Lake is 600 feet deep, and the bottom is very fine silt that's
another 600 feet deep and has been deposited since the last ice age. We were
concerned about the subs diving into that silt and getting stuck by suction,
so we held them off the bottom. One interesting thing is we could see the
subs on the boat's fish-finder. Really big fish, at 500 in the first test
and 300 feet in the second.?
Here was our M.O.:
1) Trim out buoyancy at the ramp so the sub will be neutrally buoyant with
MBTs flooded. Set the auto-pilot timer, seal the hatch.2) Tow to test
site.3) Swimmers flood MBTs and make sure to close the valves before the sub
disappears.4) Add some ballast for modest negative buoyancy. Enough to
prevent the sub from floating on a thermocline, but not so much you could
not pull her up.5) Let sub down a little, check for leaks by looking through
the view ports. We marked the rope with labeled heat shrink, at 50 foot
increments. We used a rope that was longer than the depth of the lake. It
had a trawl float 20 feet from the sub, to keep it clear from the valve
handles, and another float on the end in case we had to let it go. The rope
was not tied off on the boat, we just put a turn on a cleat and kept a hand
on it. An imploding sub could sink the surface boat.?6) Wait, tracking time
on a timer that was set at the same time as the one in the sub.7) The angle
of the line indicates w!
 here the sub is. Ensure the surface boat is not directly above when the sub
surfaces.
If anyone wants to borrow the auto-pilot for a depth test, just let me know.
I think we've used it for testing about 4 subs by now.?
I'll post some photos and video on FB...

Best,
Alec_______________________________________________
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Message: 2
Date: Tue, 31 Aug 2021 19:11:38 +0000 (UTC)
From: Cliff Redus via Personal_Submersibles
	<personal_submersibles at psubs.org>
To: Alec Smyth via Personal_Submersibles
	<personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] Depth tests at Seneca
Message-ID: <340360553.1511707.1630437098206 at mail.yahoo.com>
Content-Type: text/plain; charset="utf-8"

I thought I would put my two cents in on the Lake Seneca divesthis weekend
of Shackletonand The Great Escape (TGE).? Bottom lineis both boats were
successful in massively extending their operating depth to500 ft and 300 ft,
respectively. This is a big milestone for each of thesepsubs and they did a
great job coordinating these tests.? 

?I don?t have much toadd on the dives other than the working hypothesis of
the extruded O-ring onShackleton.? Another possible hypothesis
isoverpressure from heating of the air in the battery pod could have caused
theextrusion.? The initial pressure in the podwas ambient at the temperature
of Alec?s garage in Virginia when he closed upthe pod after the initial
charging. It is possible the top off charge causedsome pressure build but,
in my experience, the smart charger should have beenin the third phase of
charge which is high voltage, low current switching onand off.? It is hard
for me see thisgenerating the kind of pressure needed to unseat the o-ring.?
?On thetest dive day at Lake Seneca we did not get the Shackleton into the
water tillaround noon.? The temperature could easilyhave been over 100 F
from the sun.? Hotair has a lower density than cold so this could have
caused the overpressure inthe port pod in that the OP valve on the pod was
locked out.? We had multiple pe!
 ople looking at the boat fromthe time we got to the lake which I think was
around 9 am or so until the launcharound noon.? No one noticed the
extrudedo-ring which was in a very observable location being at the top of
the portbattery pod very near the bow view port.?The extrusion was about 1
inch in length.? If it had been extruded at that point, then Ithink someone
would have noticed this black 1 inch extruded O- ring against thewhite color
of the pod.? This leads me tothink the extrusion happed sometime after the
launch.? We noticed the listing on the tow out.? My guess is that the water
temperature at thesurface was on the order of ?65 F.? As such, when the
battery pods were submergedthe air in the pods stated to cool down quickly
so 1 atm air in the pod promptlydropped into a partial vacuum pulled in
water. Of course, as the boat descendedto 500 ft, this extruded O-ring
presented a flow path for the water and thehigh differential pressure
between ambient water and pod pr!
 essure flooded thepod.?? I concur with Alec in that the ABSrule that
requires the boat to be able to be surfaced with MBT blow with thelargest
non-hull floodable volume (in this case, one of the battery pods)
beingcompletely flooded saved the day.? Alecis braver than me.? I was
arguing foraborting the dive until we sorted this out.

?So the lesson learnedto me was to add a visual and tactile inspection of
both battery pod joints tothe predive checklist and as Alec notes, open the
wing nut on the battery podOP valve so that any overpressure event in the
pod would be safely vented.

Concerning the hiccup with The Great Escape on the Friday ballastcheckout
dive, in retrospect, the problem of air from deepest MBT, either forwardor
aft, forcing air into the more shallow tank could have been prevented
withtwo low-cracking pressure check or non return valves positioned on both
branchingsides of the test rig tee.? This wouldhave prevented this
longitudinal movement of air between the MBTS.? Standing on the boat
watching and excessive amountof air venting from the forward and aft MBS
while no air was being added was causingus all to scratch our heads.? It was
Dan Lancethat picked up on the problem.? 

After recovering the boat, Steve?s solution of with a quickrun to the
hardware shop for another valve ?solved the problem and the next days dive
wentoff fine except for the extra 20 minutes we waited for the boat
tosurface.? I sure thought we were going toneed our weaties to manually hall
in the boat.?Steve just kept saying, just give it another 5 minutes.

Dive operations with Shackleton on Monday were in jeopardy due to Alec?sback
which he managed to strain holding onto the line attached to Shackleton for
an hour as she sat at500ft during the unmanned depth test.? Hisonly
requirement for our Sunday night celebration dinner was a simple
straightback chair.? I thought we were going to haveto carry him out to the
car after dinner. ?Getting into Shackleton is a bit tricky even with a
goodback. In the morning he had recovered to the point that he agreed to
have a goat diving.

Alec agreedto take me for a dive as a passenger (big thanks) so below are my
observationsfrom the dive.? First Alec did a greatjob in the predive
orientation which was done in the boat.? He has a very specific instruction
on how tomove this way and turn that way to get the passenger down the sail
and into aprone on your stomach position facing the bow viewport.? I found
the layout of switches and controlsto be intuitive and well labeled. We went
through all the common systems firstincluding location of thruster breakers,
BIBS system, exterior and interiorlights, surface and underwater comms,
thruster operations and O2 makeup regulators.? After I was comfortable with
basicoperations, he covered emergency items such as drop weight and
jettisoning thrustersthat were entangled.? I think anyonegenerally familiar
with basic components of a 1-atm boat would come up to speedpretty quickly
with his layout of equipment and his orientation.

Over the years,Alec has done quite a bit of work on the MBT design mostly
due to the design objectivesof the boat changing mid stream.? As suchit is
very stable to walk on during passenger change outs.? Other than the
absolutely beautiful view fromthe bow viewport, what I was very impressed
with was the operation of the MBTpneumatic vent valves.? They are fast!
Inreviewing the video of the dive with his son Treavor as passenger, it took
12seconds from when the MBT valves opened until the boat was fully flooded.?
This transition period from fully blown MBTto fully flooded MBT can be
problematic for some boats.? Thanks to Hugh Fulton for sharing the
originaldesign of these MBT vent valves.? I lovethese valves and plan to use
them on my next boat. 

?

Of courseSteve McQueen get bragging rights for the best Eye Candy.? TGE is
just a beautiful K-250 build.? If you are wanting to fast track getting
inthe water with your very own boat, Steve has put TGE on the market.? I
don?t think you can find a better builtK-250.

One last point.? Steve DeMartino and James Eddlestone were twolocal
experienced divers that answered our call for diving assistance duringthe
trip.? They both did and outstandingjob.? Steve even opened up his lake
housefor us to use as a base of operation during the trip.? He also used his
boat as tender during the dives.? Steve did and excellent job in just about
whateverwe asked him to do in the water including acting a counter balance
on the towback with Shackleton.

It is niceto see these two boat reach a fully qualified status.

?

Cliff

    On Monday, August 30, 2021, 04:17:57 PM CDT, Alec Smyth via
Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 Hi Friends,
Steve McQueen and I just depth tested our subs in Seneca Lake, and I thought
I'd send a little writeup. But first, many thanks to Cliff Redus and Dan
Lance for crewing!?
We prepared our subs by installing temporary MBT plumbing outside, with
valves that could be operated by swimmers. The subs were to be sent down on
an anchor line, and would blow tanks an hour later automatically. The
"auto-pilot" that blows ballast uses a timer, but will also blow ballast
ahead of time if a water detector senses a leak.?
Both tests were successful, but both were also a little too exciting.?
In my case, Shackleton developed a 45 degree list during the tow out to the
test site. I was pretty certain it was a flooded battery pod, and could see
the cabin was dry by looking into the bow dome, so decided to go ahead and
send her down because, even though a flooded pod is a lot of extra weight,
the pods are sized not to result in negative buoyancy when flooded. That is
an ABS rule. The sub did indeed come back up after an hour, with the cabin
still dry.?
Once back on land, we found the source of the battery pod leak had been
owner stupidity (surprise!!!) I normally open the pods for charging, but in
this instance had thought it unnecessary because the charging was just a
really small top-up. Wrong... battery off-gassing had dislodged a pod cap
O-ring. On top of that, my pods have over-pressure valves that would have
avoided the issue, except that I'd bolted them as an extra security measure
to prevent a leak path on the test. After all, I don't think anyone else has
put OP valves on their pods so reached the conclusion they weren't
necessary. Well, lessons learned. Moving forward, caps will be coming off
during any charging, and the OP valves will go back into operation too (e.g.
to prevent against heat expansion.) The good news is that the flood does not
appear to have affected the batteries, which are AGMs. We dove the sub the
next day. All worked perfectly and the battery voltage had not decreased in
the slightest.
Steve's sub, The Great Escape, had a minor issue involving the temporary MBT
plumbing. Steve had plumbed both MBTs together, to a T, and put a ball valve
on that. What happened was a siphon effect between the two tanks. Whichever
MBT was slightly lower in the water would transfer air to the higher one,
from which it would escape. Steve redid the temporary plumbing, putting a
separate ball valve on each tank, and the issue was fixed. His test went
well, except he was conservative turning the knob on the timer, so the
autopilot went off about 20 minutes later than planned - and he probably
aged 20 years in those 20 minutes.?
Seneca Lake is 600 feet deep, and the bottom is very fine silt that's
another 600 feet deep and has been deposited since the last ice age. We were
concerned about the subs diving into that silt and getting stuck by suction,
so we held them off the bottom. One interesting thing is we could see the
subs on the boat's fish-finder. Really big fish, at 500 in the first test
and 300 feet in the second.?
Here was our M.O.:
1) Trim out buoyancy at the ramp so the sub will be neutrally buoyant with
MBTs flooded. Set the auto-pilot timer, seal the hatch.2) Tow to test
site.3) Swimmers flood MBTs and make sure to close the valves before the sub
disappears.4) Add some ballast for modest negative buoyancy. Enough to
prevent the sub from floating on a thermocline, but not so much you could
not pull her up.5) Let sub down a little, check for leaks by looking through
the view ports. We marked the rope with labeled heat shrink, at 50 foot
increments. We used a rope that was longer than the depth of the lake. It
had a trawl float 20 feet from the sub, to keep it clear from the valve
handles, and another float on the end in case we had to let it go. The rope
was not tied off on the boat, we just put a turn on a cleat and kept a hand
on it. An imploding sub could sink the surface boat.?6) Wait, tracking time
on a timer that was set at the same time as the one in the sub.7) The angle
of the line indicates w!
 here the sub is. Ensure the surface boat is not directly above when the sub
surfaces.
If anyone wants to borrow the auto-pilot for a depth test, just let me know.
I think we've used it for testing about 4 subs by now.?
I'll post some photos and video on FB...

Best,
Alec_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

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