Ships boilers

Propulsion systems, machinery, turbines, boilers, propellers, fuel consumption, etc.
paul.mercer
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Ships boilers

Post by paul.mercer » Thu Jul 16, 2020 9:34 pm

Gentlemen,
Not sure where to place this, but here it is anyway.
A question I have often wondered about, when a ship sinks could the sudden rush of cold water cause the boilers to explode?

OpanaPointer
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Re: Ships boilers

Post by OpanaPointer » Sat Jul 18, 2020 12:15 pm

paul.mercer wrote:
Thu Jul 16, 2020 9:34 pm
Gentlemen,
Not sure where to place this, but here it is anyway.
A question I have often wondered about, when a ship sinks could the sudden rush of cold water cause the boilers to explode?
With an internal pressure of (up to) 1200 psi and temperatures of (up to) 900 F and a sudden failure of the structure due to cold water shock, yeah, the shit could hit the fan. I was a "pit snipe", working in the engine/boiler rooms and we were always aware of the possibility of catastrophic failure. The "safety valves" were supposed to dump the pressure, IF there was time enough to activate them.

paul.mercer
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Re: Ships boilers

Post by paul.mercer » Wed Jul 22, 2020 9:04 am

Many thanks for your reply,
what is a 'pit snipe' and how did it get its name

OpanaPointer
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Re: Ships boilers

Post by OpanaPointer » Wed Jul 22, 2020 11:39 am

paul.mercer wrote:
Wed Jul 22, 2020 9:04 am
Many thanks for your reply,
what is a 'pit snipe' and how did it get its name
The "pit" probably arose from Dante's Inferno. You go down, down, down, down to get there. And it's hot as hell most of the time. In the coal fired boiler days that doors had to be opened to add coal, so the heat gradient wasn't all that much. The term "gutter snipe" was common usage for orphans living in the big cities in the late 1800s. They were a ragged, dirty lot and the coal dust covered engineering crews reminded many of those lost souls.

I did a semester reading on class distinctions in various navies when steam power came about. Most countries would bar an Engineering officer from getting a ship's command position, and Germany (among others) only allowed Jews to be Engineers. This resulted in an Engineering Commander being secondary to a "Line" Ensign in some cases.

Bill Jurens
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Re: Ships boilers

Post by Bill Jurens » Wed Jul 22, 2020 8:17 pm

The situation depends upon the type of boiler in use. Fire-tube boilers, which were not used much in warships after about 1905 or so, contain a good deal of superheated water that can flash into steam if the pressure vessel complex is breached. But, in practical terms, this rarely happens because in rapid flooding situations the water surrounding the boiler can absorb most of this energy with relative ease. On land, with the boiler surrounded only by air, this can cause a very catastrophic explosion indeed. But when water is invoved, the situation is different. There are good examples of the differences involved with regard to the record of steam locomotives which, for some reason or another, fell into adjacent rivers and lakes etc. in the process of derailing. Explosions in these cases were rare, whereas catastrophic explosions where the boiler was not semi or fully submerged -- were much more common and very much more spectacular.

In general water-tube boilers do not contain enough working fluid, i.e. steam/water, at any given time to create a serious explosion, especially if the boiler is partially or fully submerged. There are, so far as I know, virtually no cases where water-tube boilers exploded during flooding situations. That does not mean that the surrounding crew is safe, but there is generally just not enough instantaneous energy contained in a water-tube boiler to cause anything like a catastrophic structural explosion or failure of surrounding bulkheads, etc., especially when the steam is rapidly condensing when coming in contact with incoming seawater, etc.

Bill Jurens.

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marcelo_malara
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Re: Ships boilers

Post by marcelo_malara » Sun Jul 26, 2020 5:43 pm

Thanks Bill. I strongly recomend the book Titanic Ships Titanic Disaster (coauthored by W Garzke):

https://www.amazon.com/Titantic-Ships-T ... 093977335X

Apart that it is an excellent book, almost unknown, they do an analysis about the question of exploding boilers, coming to the conclusion that it was in fact a rare occurrence.

Regards

Bill Jurens
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Re: Ships boilers

Post by Bill Jurens » Wed Jul 29, 2020 12:10 am

Yes. Bill Garzke is a close friend of mine, so I have had a copy of this book for years now. It is a nice treatment, and it's likely that I actually helped in completing parts of it. Memory fails...

Bill Jurens

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