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Occasionally, we stumble across a problem of great
significance of which no one is aware.
That happened to me once and there is a little drama and a touch of
humor in it.
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* * * * * * * * * * * *
We were off the coast of Viet Nam on a summer day
in 1967. My ship, the Waddell, was providing gunfire support
to troops ashore. I was in the plotting
room, in charge of the ship’s 5”/54 guns, its main battery. We were in the midst of a mission.
Up in the Combat Information Center (CIC), the
Gunnery Liaison Officer (GLO) informed me that the spotter, in a light plane a
couple of miles inland, has just made an odd request and the GLO wanted to know
if we could respond. The spotter’s
request was for us to “throw a couple of rounds as far down the gun target line
as we could throw ‘em.” It seems the
spotter had a target he suspected was out of range but he wanted to make
certain. So, he asked for two rounds at
maximum range along the same line we had just been shooting.
Maximum range, in a vacuum, is achieved at a gun
elevation angle of 45 degrees. I
couldn’t do anything about not being in a vacuum; the atmospheric conditions
were what they were and they had been entered into the computer and compensated
for in its calculations of gun orders.
The more vexing problem was that, owing to the pitch and roll of the
deck on which the guns were mounted, there was no way of manually setting the
guns at that angle and keeping them there.
But the gulf waters were especially calm that day. As I observed the dials indicating pitch and
roll I could see that pitch (up and down) was not a factor and roll (side to
side) was less than one degree. At 45
degrees of elevation, it would take more than a degree of roll to shift the
mean point of impact of any rounds fired by 100 yards. Satisfied that accuracy would be acceptable,
I removed the amplifier that controlled the gun elevation order module and hand
set it to 45 degrees. In short, I
“jury-rigged” the computer controlling the gun mounts. I then reported ready to
the GLO.
We fired one round then waited. The spotter came back with a request for six
rounds of rapid continuous fire; then six more behind that. Suddenly, over the radio circuits, we heard
him exclaim, “Hot damn! Secondaries!” He
was referring to secondary explosions caused by our gunfire. It turns out we hit an ammo dump. All with the gun elevation order manually set
to 45 degrees.
Later, done for the day, we steamed off to a
different assignment (with the amplifier reinserted in the gun fire control
system computer, of course). As we
steamed off, I wondered just how far those rounds had gone, so I asked the GLO
if he could back-track, checking the charts used up in CIC to see where we were
at the time, where the coordinates for the target were, and what the distance
was between them. In a few minutes, he
told me that the distance to the target we fired at and hit was just over
26,000 yards. I was flabbergasted
because that was 3,000 yards farther than those particular guns were supposed
to be able to shoot and 6,000 yards farther than range the gun fire control
system was designed to use. The supposed
maximum usable gun range of that system was just under 20,000 yards.
I spent the better part of the night poring over
the manuals for that system, trying to figure out why we could shoot so much
farther than the guns’ supposed maximum range.
Finally, as I sat looking at the range tables for the gun, I gave up. I closed the range table book and, as I looked
at the cover, the nature of the problem dawned on me.
The cover of the range table book indicated that
the initial velocity (i.e., the speed of a projectile upon leaving the barrel
of the gun) was 2,500 feet per second.
Well, that particular gun had an initial velocity of 2,650 feet per
second. The range tables were
wrong! And that meant the design of the
gunfire control system was flawed. So, I
spent the better part of the following day calculating some crude adjustments
to the range table values and converting those to a system of elevation spots
that could be inserted into the computer to take advantage of the unused
capability of our gun system. We then
spent several days blowing up things the enemy thought were safely out of
reach.
Later, one night after I had worked out the
extended range procedure and while we were still on the gun line, I was called
to the bridge. The skipper informed me
that a sister ship (a ship of the same class) was having a problem and he
wanted me to listen to the radio traffic.
It was a nighttime mission and it involved starshells (projectiles that
served to illuminate targets). The
spotter would get the illumination right, then shift to high explosive rounds
and they would be way off in relation to where they should have been. I went below, checked the starshell range
tables and found the same problem. I
quickly worked up a set of correcting spots, returned to the bridge and
explained to the skipper what I had found.
We contacted our sister ship by voice radio, arranged for them to bring
their Chief FT to their bridge and I explained to him in plain language over
the airwaves what was going on. The
adjustments were being transmitted via different means. Shortly thereafter, it was clear that the
adjustments were working; the illumination projectiles and the high-explosive
projectiles were both where they should have been.
I wrote up the “extended range procedure” as I
called it and submitted it to the admiral in charge of the task group of which
my ship was a part.
Later, when we left the gun line and returned to
Subic Bay in the Philippines, the GLO and I were told to report to the admiral
in charge of the task group. He wanted
to know what that radio traffic had been about.
We reported to the admiral’s ship and, just in case, I took along my
copy of the extended range procedure.
After some brief pleasantries, the admiral asked the GLO what that radio
traffic between us and our sister ship was about. The GLO deferred to me and I explained the
“glitch” in the weapons system. I also
mentioned that I had written it all up and submitted it to the admiral a couple
of weeks earlier. He looked puzzled,
then reached for his intercom and called in a lieutenant on his staff.
“Jim,” said the admiral, “have you seen anything
about an extended range procedure, something to do with a flaw in our 5”/54 gun
system?”
“Yes, sir,” replied the lieutenant, “but I tossed
it. There’s no way there could be that
kind of hole in one of our weapons systems.”
The admiral thanked the lieutenant who returned
to his office.
Turning to me, the admiral said, “You’ll have to
excuse him, Chief; he’s young.”
I allowed as how it was not a problem and gave
the admiral my copy of the extended range procedure. On an interim basis, that procedure was
published in guidelines distributed to the task group. Eventually, the gunfire control system in
question was modified so as to take advantage of that extra 6,000 yards.
