Navy showers and the steam cycle

By lex, on January 8th, 2005

Which is a sea story, combining a few of the exquisite luxuries of shipboard life, with some elemental discussion of the steam cycle.

Because I don’t think it’s been done, before.

The first thing you have to understand is that Guilt is the flip side of Duty.

And in the Navy we understand both concepts all too well. Duty of course, is what drives our daily existence – I have duty today, you might say. Or, I must do my duty. And, Duty calls. Do your duty in all things, R.E. Lee advised – you cannot do more, you should never wish to do less.

And off you go, or else you get walloped over the head with the wooden spoon of guilt.

My mother had been raised Catholic, so she understood intuitively where to find the cracks and fissures in that union of soul and self wherein to place the psychic levers of guilt. Although her marriage to my Baptist father had resulted in my own compromise initiation into the mysteries of the Episcopal church (“Catholic lite – all the ceremony, none of the guilt”), my attendance at a Catholic high school ensured that the grounds of my consciousness were a fertile place for the seeds of the Navy’s own brand of guilt culture to make their purchase.

My first fleet deployments were aboard the USS Constellation and USS Independence. They were steam ships, driven by eight massive, diesel fuel (marine) driven boilers – the Nimitz class super-carriers which now make up over 80% of our inventory, with their nuclear power-driven steam turbines, were still regarded as something of an innovation when I joined the fleet.

And the thing you learned about almost right away when joining a steam ship at sea was that fresh water was far more precious a commodity than your opinion. Between providing hotel services for 5000 people (fresh water for cleaning clothes and dishes), hygienic uses and of course, drinking water, the ship produced via her evaporators right around 1 million gallons of fresh water every day. And used just about every drop of it, every day. If water usage for whatever reason exceeded water production, the ship would be placed on “water hours” – its use would be restricted to certain times. There was a prioritization scheme as well – paper plates and plastic forks replaced the normal cutlery. On extended water hours the smell on board could get fairly ripe, since it could be difficult to work your personal schedule around shower availability. And it was clearly the Chief Engineer’s point of view (and his point of view mattered, he was the guy who, among other things, made the water) all that loose talk about hygienic uses and death by thirst (can’t they drink coffee?) paled in significance to this: Fresh water was also required to run the boilers.

And when the nearly 2000 man air wing contingent joined the ship’s company to fully round out the manning complement, it was made quite clear to us that every drop of excess usage was our fault – every time the water levels started to drop, we were to blame. The ship’s company could not conceive that any of their personnel would take “Hollywood” showers – as dedicated members of the crew, wedded to the ship as it were, they all knew that each of them took “Navy showers” – the kind in which you sprinkle just enough water to wet yourself, then turn the water off to soap up vigorously, and then rinse – briefly. The showers in fact were designed for such use in mind – a hose led to a fist-sized nozzle with a spring-loaded release valve. Next time you’re in the shower, imagine directing the water upon your skin with one hand and trying clean yourself with only the other, and you will understand the system.

So. High usage? The air wing’s fault. Probably those spoiled and pampered pilots.

And we, the member’s of the air wing? We understood – it was our duty to keep the water usage low, and when it peaked, we accepted the guilt.

In no small measure because we honestly felt as though we’d earned it, collectively. Water production and level maintenance was the Chief Engineer’s problem, not ours – our job was fleet defense, and bombs on target / on time, and getting aboard the first time. Plus, being innovative souls at heart, there were no shortages of c-clamp devices cradled in coat hanger harnesses designed to hold the shower nozzle in just the right position (with the water valve continuously depressed) to ensure that nice, long, relaxing, two-handed Hollywood. So when water usage spiked (inevitably in some steamy foreign clime), and water hours were imposed, we blamed ourselves.

Our bad.

For whatever reason, the water usage issue is much more of a problem on the steam ships than it is on the nukes. I made one deployment on a nuke in my career, the other six, plus their associated work-ups, were on conventional steam ships. So I got used to feeling guilty about water, over the course of my career.

The last two deployments were as Operations Officer of a conventional steam ship – as ship’s company. And not merely any job in the ship’s company, but as a ranking department head, a part of the inner sanctum, a member of the shipboard illuminati, if you will. I got to observe the inner workings of the several departments at close hand.

I also was refreshed on the steam cycle, something I had studied at the Boat School, but hadn’t, as an FA-18 pilot, paid a great deal of attention to in the intervening years. Not to worry, it hadn’t changed much, if at all. From the Engineer’s Edge :

1-2: Saturated steam from the steam generator is expanded in the high pressure (HP) turbine to provide shaft work out put at a constant entropy.

2-3: The moist steam from the exit of the HP turbine is dried and superheated in the moisture separator reheater(MSR).

3-4: Super heated steam from the MSR is expanded in the low pressure (LP) turbine to provide shaft work output at a constant entropy.

4-5: Steam exhaust from the turbine is condensed in the condenser in which heat is transferred to the cooling water under a constant vacuum condition.

5-6: The feed water is compressed as a liquid by the condensate and feed water pump and the feed water is preheated by the feed water heaters.

6-1: Heat is added to the working fluid in the steam generator under a constant pressure condition.

LexNavyShowers

The boilers are used to provide the heat to generate steam from feed water – feed water has to be fresh water, to keep all kinds of nasty chemical reactions and residue scaling from gumming up the works. As the steam is generated in a constant volume space, pressure increases (Boyle’s Law ). Work output is gained by siphoning off the pressurized steam through the high and low pressure turbines. These turbines crank mechanical gear, like the main engine shafts and auxiliary equipment boxes (heat, light, etc.). On an aircraft carrier, some of the steam is siphoned off to run the catapults, which means that new feed water must be generated to make up for the overboard losses each time we shoot a jet off the front end. The condenser is used to return the exhausted steam to liquid state to start the process all over again.

The condenser is essentially a massive heat exchanger – the dead steam is run through a box which is itself transpierced with hundreds or thousands of metal pipes, themselves carrying cold water. The steam condenses around these pipes, drips to a collection box and is returned back to the system for further use by the condensate and feed pumps.

Where does the cold water in pipes that transpierce the condenser come from, Lex? I’m glad you asked, constant reader — it comes from the sea, mother to us all.

Salt water, in other words.

Would it surprise you, gentle reader, to learn that over the course of the years a chemical process occurs aboard ship – a process involving the interaction of certain compounds found in salt with the oxygen molecules found in water, known to scientists as “oxidization,” to engineers as “corrosion,” and to the lumpen proletariat as “rusting?” That during this frequently observed process, known to children, that one or more, if not several, of these transpiercing condenser tubes, containing sea water (from the ocean, mother to us all) might leak into the gathering feed water at the bottom of the condenser tank?

That such a process is known as “salting the boiler,” and has nasty implications on such arcana as boiler chemistry, which in turn affects the long-term health of the engineering plant?

Probably not. I bet you’re not one damned bit surprised. You are all clever, clever readers.

But what you probably don’t know, because I didn’t, is that once this phenomenon occurs that boiler must be shut down and the condenser tubes repaired or replaced. But wait, there’s more: The real kicker is that the condenser tank, and potentially much of the rest of the boiler, has got to be flushed down but good with fresh feed water. Lots of it. Or else.

And what I found even more curious, after a lifetime at sea in the throes of aviator guilt, is that there was a much higher correlation between water hours and salting the boiler than there was between water hours and Hollywood showers. But I can’t ever recall having heard the Chief Engineer come up on the announcing system to apologize for salting the boiler, and the necessity of setting water hours.

No.

It was always those darned aviators.

Amazing what you can learn, in the inner sanctum.

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1 Comment

Filed under Best of Neptunus Lex, Lex, Uncategorized

One response to “Navy showers and the steam cycle

  1. Pingback: Index – The Best of Neptunus Lex | The Lexicans

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