Battery  Water
by  Norm  Hammond
One of the duties of enginemen on the Thornback was to run the stills that made fresh
water from seawater.  We made drinking water for everyday use, and also battery water for
the tons of tons of batteries that powered us underwater.  Over time, those batteries would
lose considerable water through evaporation and it had to be replaced with water of much
greater purity than the water used for drinking and bathing.
One of the members of the deck gang decided to "strike" for engineman, and  was sent to
be my "oiler" in the F.E.R.  I showed him how to balance the electrodes and compressors
on the stills, and how to test the water before we sent it on into the fresh water storage
tanks.  The test cock was down in the engineroom flats, under the stills, and the sample
had to be drawn from there.
A battery powered test kit was used to measure the resistance caused by impurities in the
water, measured in parts per million.  The water sample was drawn into a small cube-
shaped cup on the tester, then tested and the results recorded.  After that the sample was
just poured into the bilge.
Part of an oiler's duties was to go down the ladder into the lower flats every fifteen minutes
and take engine readings, then enter them into the log.  When I saw the tank from the still
was nearly full, I would have the oiler take the test kit with him when he went down to get
the readings so he could test the water while he was down there.
We were short of drinking water, so we had to fill those tanks before making water for the
batteries.  We finally topped off the drinking water tanks and then fine-tuned the stills to get
the water purity to an acceptable level for the batteries.  When the next tank was full, I sent
the oiler down to test the water.  It tested slightly better than the drinking water we made,
but it was not good enough for the batteries.  We had already filled the drinking water
tanks, so we had no option but to blow the water over the side and try again.
I used every trick I knew to fine-tune the stills, and on the next tank we got the same
results.  The next tank was the same, so I knew we had to be doing something really
wrong.  I thought of everything, and finally decided there had to be something wrong with
the testing procedure itself.
When the tank was full again, I had the oiler take the test kit back down the ladder into the
flats.  I crept over to the hatch and watched as he drew the sample.  Then I saw him pull
the little glass container with the sample out of the test kit (which he wasn't supposed to do
until he was ready to dump it) and hold it up to the light and carefully examine it.   I was
appalled as I saw him cover the open end of the glass container with his grimy engine room
thumb and shake it!
He held the sample up to the light again and looked at it carefully, and put it back in the
tester.  He took the reading and recorded it, then poured the sample into the bilge.  He put
the container back in the tester again, and started back up the ladder.
When he got to the top of the ladder he saw me standing there laughing!  I explained to
him that the water was not acceptable for battery water because he had introduced all
those parts-per-millions of impurities with his thumb.  I certainly didn't tell him to do that as
part of the testing procedure, but I guess the laugh was on me because I hadn't told him
not to either!
I sent him back down the ladder to take another sample of that tank and test it again; this
time without using his thumb.  This time the water was about as pure as it could get.  That
tank and the others that followed went into the battery water tanks just fine, and a few
watches later my new oiler decided he wanted to go back into the deck gang…
19  Jan  2006
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