Sunday, March 23, 2008

Ping Time

Before I get to the story itself, first, you need some background information, so please bear with me.

Between the 1960s and the retirement of the steam tin cans in the 1990s, a number of them were equipped with the AN/SQS-26 sonar. The SQS-26 was a big sonar. If you compared a soft whisper to the sound of a very large jet airliner taking off and then used that scale to measure the sound of a SQS-26, the whisper would be the sound of the jet and the jet would be the sonar.

The sonar was so powerful that it could not be powered directly from the ship’s electrical system. A large motor spun a flywheel, which, in turn, spun a generator. That generator charged a bank of capacitors. These were not the kind of capacitors you could buy at Radio Shack, each capacitor was roughly the size of a quart juice can. If you shorted one out with your hand, your hand likely would be blown off. And there were a lot of capacitors in that bank. The whole lashup of motor, flywheel, generator and capacitors was the Louis-Allis Power Supply, known as Louie-Allis or LAPS.

This is the transducer array of a SQS-26:
A very large rubber radial belt goes around the front and sides to make up the dome's exterior. Each one of those black squares is the rubber face of a transducer element. You can roughly get an idea of the size of each element by comparing them to the worker in the background. There are hundreds of elements. When mounted on a ship, it looks like this:

This is the sound of one. That is what it sounded like if you were in a submarine and an SQS-26 was pinging on you from some distance away.

Every so often, the sonar techs had to measure the output and noise levels of the sonar, in order to do something or other. This was done in port; the sonar techs would hang a transducer from a pole so that it dangled in front of the sonar dome. And then they would ping away. This could only be done after normal working hours and with the permission of the naval station commander, for if a diver were in the water anywhere else in the the naval station when a SQS-26 pinged, the diver would be lucky if he only was rendered totally deaf for life. That level of sound could disorient a diver, who might then drown. Also, only one ship at a time could do the check to avoid mutual interference. You either got used to the sound of a sonar pinging at night or you didn’t get any sleep. And this check was done on just a few elements of the sonar for any one ping, by no means was the full power of the sonar used.

Now this is no shit:

A particular naval station had a bit where the ship at any given pier who had the senior-most commander was in charge of the security and good order of the pier. Those unlucky ships were known as the “Pier SOPA” (senior officer present afloat). It was a real pain in the ass to be the Pier SOPA.

One afternoon, the young lieutenant junior grade who was the Command Duty Officer of the ship that was the Pier SOPA looked out on the pier and saw that there was a really disorderly mess by one of the ships. That ship was across the pier from the Pier SOPA. It was a “United States Naval Ship,” which is an auxiliary ship (cargo, oil tanker) that is technically in the naval service, but which was commanded and crewed by civilian merchant mariners. USNS ships don’t do a lot of the mickey-mouse stuff that USN ships do.

The CDO had the Messenger of the Watch go over to the USNS ship and ask them to clean up their stuff on the pier and to tell them that if they didn’t, a working party would be sent to get rid of it. The CDO knew that the naval base duty officer would, sooner or later, make a tour of the piers and then the CDO would get chewed out for the slovenly condition of the pier.

Within five minutes, the Messenger was back with this message: “Lieutenant, the XO of that ship says that if we touch any of their shit on the pier, he will personally break your fuckin’ neck.”

As it turned out, the sonar techs of the Pier SOPA's ship had permission to ping that night. And it was after working hours. The CDO had the word passed for the duty sonar tech. When he showed up, the CDO ordered the sonar tech to light off Louis-Allis and get ready to start pinging on command.

The CDO went to Sonar Control and opened the door to the topside weather deck. By now, Sonar Control had a number of sailors in it, who had figured out that something good was about to happen. The CDO looked out the door and told the tech sitting at the console to switch to “track mode” and swing the track bearing to a relative bearing of 250 degrees.

Track mode concentrated all of the enormous power of the sonar into a beam of less than ten degrees in width. As you probably have guessed a relative bearing of 250 degrees aimed that beam at the USNS ship. The CDO ordered the sonar set for a short range scale (frequent pinging) and gave the order to start pinging.





The effect on the USNS ship had to be akin to sticking one’s head inside of a large church bell while someone beat the living shit out of it with a heavy sledgehammer. The USNS ship looked as though someone had kicked over an anthill, as people came boiling up topside from below decks. In a few minutes, the Messenger of the Watch reported to the CDO that the XO of the USNS ship sent his respects and asked if the pinging could cease. The CDO told the Messenger that while the Pier SOPA had permission to ping, it could stop for a little while and oh, by the way, it’d be appreciated if they could clean up their shit on the pier.

The USNS ship had about 20 seamen on the pier in five minutes, squaring their stuff away. The Pier SOPA ship stopped pinging until the sonar techs were ready to do their checks. The naval station duty officer made his or her drive-by inspection and had no comments. And when the Pier SOPA had any future requests of that USNS ship, the USNS ship’s crew could not have been more accommodating.


Bustednuckles said...

Ya gotta love a good one like that.
Fuck with me will ya?

physioprof said...

That's fucking hilarious! I wish I had one of them big-ass motherfucking sonar doohickeys in my blog!

David said...

We had a new bright and shiney ASW Officer, straight outta the Academy. He wanted us to try these new pre-underway check lists. It calls for the sonar to be pinged in omni after the ship (steam powered FF) was on stable ships power. Light-off of the boiler was after lunch, so stable ships power was around 0200 hrs. We were in Alameda, tied up outboard of a carrier and there was another carrier on the next pier over. Effectively, we were moored between two deep draft ships. When we lit off the CX in omni mode, it seemed to reverberate through out the entire bay! Needless to say the ASWO came running up to Sonar Control only after we had been pinging for a few short minutes. We never had to do pre-underyway checks ever again.

Comrade Misfit said...

Not a CXR? said...

Nice to see a JO win one, once in a while.

Randy Jordan said...

We tried something similar, we got cut off by a cruse ship pulling into San Juan for a weekend liberty after GitMo training. We 'tested' our Bottom Bounce mode with 0 Depression against their hull, to calibrate against the Radar guys readings. A very early wakeup call (05:00). Yes, we were properly calibrated after several pings. :-)