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[PSUBS-MAILIST] Re: [PSUBS-MAILIST] A voyage on Nautilus, and the story of the boyancy crisis...and how we almost lo
Hi
Peter,
some of our expirence here - winter is coming, be
carefull with frotzen vales, pipes or openings !
We can tell some
storys about frozen vales on Nemo and Peppers.
One thing I
have learned : in case of something went wrong - close the dammed
hatch(es) !
Special if you launch a boat on a slipway, test
the tank system, or boat gets unstable, situation is unusable,
gets
wrong trim, has a leak, fire in the engine room, crazy people on the
masterstation, realy bad weather or a fast big tug boat pass alongside..
Submarines with close hatches can survife many kind of
accidents - submarine with open hatches not..
The great
pictures of UC3 under own power are a really good motivation to get my
boat ready..
Do you manage to make the picture: Freya, Kraka and
Nautilus in on picture?
vbr Carsten - and still 1243 hours to
do..
-----Original Message-----
Date: Mon, 25 Aug 2008 21:32:39 +0200
Subject: [PSUBS-MAILIST] A voyage on Nautilus, and the story of the
boyancy crisis...and how we almost lost control...
From: UC3 NAUTILUS <uc3nautilus@hotmail.com>
To: <personal_submersibles@psubs.org>
Dear Psubbers,
One of the things that are quite
seldom here is operational stories - what you experience when going out
with your subs. Half an hour ago Nautilus arrived at her base with me a
serious lesson richer - and here is the story...of the boyancy crisis
and how we almost lost control...
Todays voyage was to start
at 1400 hours, with the crew arriving at 1300. We intended to take a joy
ride through the Copenhagen Harbor, and into the sound - ending at our
northern base. Its about 8 nautical miles and we expected to sail for
about two hours.
We had a very special crew, and a very
special guest - Richard. R. is a "very high ranking" retired
US navy submariner - who at age 70 visited the Nautilus. He has had the
command of several US diesel and nuclear submarines. Also we had Daniel,
a former Danish navy submarine TKO - technical officer and one navy
surface ship navigator. Ad two navy seals - off duty - and you have a
crew with quite some experience.
Nautilus performed very
well, and as we passed the shipyard area where she was build, we came
ashore and visited the drydock where Kraka lies. She is operational, but
disused and awaits going to the Danish Technical Museum. All the crew
were most happy, in no small part Richard. The new coffee machine in the
gally was tested and worked well.
Into the sound we
increased speed to flank. We had three person in the sail, no fuel in
the tanks ( we run her from a jerrycan ) and all tanks blown. As a
result the stability margin is marginal - al as expected. We had som
osciliations giving some 30 deg. swings as we whent flank speed, som we
discussed ways to increase stabilty. One of the questions to be asked is
if the free uncontroled water surface in the main tanks will make the
boat more unstable than the potential stabilicing effect of the boat
deaper in the water. To test this we came to stop, and manually wented
air from the fwd and rear main ballast tanks.
The boat is
not finished. There are no blowing tubes or valves inside, but form
outside - via a hose you can blow the tanks. Also the diving valves at
this stage can only be operated from outside.
The fwd. valve
was opened, and this tank floded about 50 %. The rear tank was opened,
and it floded about 50 %. Nautilus was lying at a deep trim - her fwd
hatch closed, and with a free board of about 2 meters to the sail hatch.
Aparently stable...
Then one of the deck crew reports -
"Sir, - we are still sinking in the stern" And yes - the rear
diveplane was now slowly submerging...ok - I go check the valve, its
closed and tight...but we are still sinking slowly...water begins
covering the rear deck...
I gues I build submarines in part
to feal that thrill...Ups...did we mis a step here ?...like mission
control in Houston you start to figure out - what in the hell is going
on - while staying calm. You try to be in advance of the situation - How
deep will we except this to go - what actions need to be taken - how
much boyancy do we have in the sail - what is the mechanisem behind
this...
Then mr. Madsen, Master and Comander of his home made
submarine flotilla - realises that the rear trim tank - enourmours at
some 1.5 m3, is floding uncontroled due to a flange remowed ( to mount
the new tube. )
Frankly - at this point I did not know when
this was going to be stable. We could have ended up much like the U-505
( se pic from her US navy capture ) with only the top of the sail and
the bow above water. If so, I would have ordered the sail hatch closed -
engine shut down and the crew out of the engineroom and on deck. Likely
our fwd hatch would never have gone under since most of the bouyancy in
the bow was still there. At the end - with both hatches closed the boat
would stay surfaced a some angle, but holy shit, how stupid can a man be
?
As it was Nautilus stabiliced with the water just below
the deck level, and with the bow at about normal trim. No problem at
all, Kraka has lived her life like that - but this was not because of my
talent or smartness, no - just simple luck.
Carsten and his
Germans will now tell me how stupid I am - and I agree. I for my part
told Richard the story of the Seydlitz, a German WWI battlecruiser
returning to port after the Battle of Jutland with all of the fore deck
under water...only to be repaired and returned to service...and scuttled
at Scarpa.
The good thing about it was that everybody was
calm and working together to finde the cause - and we quickly did - and
then we continued at slow first. Indeed with her tanks part floded
Nautilus was far more stable, and we increased to flank speed while
seeing the bow raising under the hydrodynamic force of the rear planes.
( so are we going to sink when we slow down ?! )
We did not -
we got fine to port, blew the tanks, and there she is safe and sound.
Richard, our navy comander - gave me a US Navy officers
badge, and said a lot of nice things - that I really fell I don´t
deserve after this ordeal that was all my fault - but I have decided to
learn from it. Not so much in the detail - since its a specialty - that
we will never see again, but as a lesson in the safe operation of big
dangerous machines. I may sound stupid, but whenever you get to the edge
of what you have done before, slow down, analyse carefully before taking
the next sted. I failed to do so - because of the exelent way the boat
and crew was performing in other irralevant ways.
The missing
part for that flange cost about 2 US doller.
Have a nice day
- and don´t play with water with out adult attention...
Best
regards,
Peter
Hold dig opdateret på dagens Gossip. Få messenger på mobilen.
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