4 ms·

Can someone explain the comment in the article about the ship going at full speed because they were fighting the fire by throwing the burning coal in the furnac

Can someone explain the comment in the article about the ship going at full speed because they were fighting the fire by throwing the burning coal in the furnace? I would have thought there would be some valve somewhere that can be opened to vent excess power (steam?) into the atmosphere rather than being forced to drive the propellers faster, is that an incorrect assumption?

dboreham 8y ago
I don't know, but I do know (based on reading old Engineering text books from my Dad) that steam power is way more complicated than you might imagine. So I suspect it is possible there is no easy way to vent it while still maintaining acceptable forward motion. It is also possible they just liked the idea of going fast.
- AnIdiotOnTheNet 8y ago
  Most things people don't have experience with are much more complicated than they imagine. It is a valuable concept to keep in mind.
userbinator 8y ago
That part didn't really make sense to me either. I believe there's a throttle valve leading to the engines, and there are relief valves to vent excess steam. It might be that those valves aren't meant to operate continuously, however. I suppose a visit to archive.org's collection of old steamship books could yield a definitive answer.
jacobush 8y ago
Maybe they didn't want to let good fuel go to waste.
- pjc50 8y ago
  Given that they need a certain amount of fuel to cross the Atlantic, this makes sense - I suppose that disposing of it otherwise would run the risk of running out of fuel.
rypskar 8y ago
If I remember correct from reading about this some years ago. They where low on coal and with the rate the fire did burn coal they needed to burn it in the furnace to get as much speed as possible, to get to the harbor before running out of coal.
- expertentipp 8y ago
  Sounds like an analogy to an economy and how the money in it is borrowed, created, and spent.
nohat 8y ago
According to one theory presented they were simply trying to use up the coal in the smoldering bunker, thereby putting out the fire.
dexen 8y ago
Running out of fuel aside (as mentioned by rypskar), they may have also needed to conserve the boiler feedwater[0]. The boilers need well distilled water to turn into steam without leaving scaly residue all over the place. During normal operations the steam is routed through engines where it expands and cools and eventually through condensers where it condenses back into water to be fed to the boilers back again. If they throttled the engines down, the excess steam would have kept gathering, increasing pressure. They'd need to either lower the coal feed rate - which they did not want - or blow off steam [1]. Ability to blow off steam is a safety measure not meant for regular, extended operations. Think "analogue of nuclear reactor SCRAM". It causes loud release of huge unseemly clouds of steam, but more importantly it causes loss of the valuable distilled water for the boilers. Btw, operations of marine steam powerplants is surprisingly complex and fascinating subject; consider having a look at this WW2-era navy manual [2] if you ever wonder what it takes to run one such at top power or efficiency. [0] https://en.wikipedia.org/wiki/Boiler_feedwater https://en.wikipedia.org/wiki/Boiler_feedwater [1] perhaps they could route some of the steam directly from boilers to condensers, but I don't think typical condenser installations are capable of directly taking in HP steam [2] https://archive.hnsa.org/doc/destroyer/steam/index.htm https://archive.hnsa.org/doc/destroyer/steam/index.htm
- magduf 8y ago
  Given that all you need to create more distilled water is heat, I'm surprised they didn't have a way of generating distilled water with excess heat from the boiler.
  - dexen 8y ago
    Honestly I am speculating here wrt distilled feedwater, essentially just geeking on a subject I happen to enjoy :^) Any ship installation is limited in size, weight, and power, so you carry machines only big enough to produce sufficient supply for normal operations plus a bit of spare capacity. Even if they had a distilling machine(s) on board, they would certainly not be able to supply as much water as they'd be able to boil off in the main boilers. Also, the apparent ease of distillate production is a bit misleading. In fact, it is a bit of an involved subject, with multi-stage processing, and delicate balances of pressures and the occasional thorough cleaning. At least in the submarine world[1], that is... Basically you want to heat up the water only as much as you need to, but later on recover as much as possible of the heat from both the distillate and the condensed discharge. This is helped greatly by maintaining proper pressures at different stages. Otherwise you'd be running exceptionally inefficient process, and at scale & over span of weeks things add up to real numbers. [1] https://archive.hnsa.org/doc/fleetsub/still/index.htm https://archive.hnsa.org/doc/fleetsub/still/index.htm

dboreham 8y ago

I don't know, but I do know (based on reading old Engineering text books from my Dad) that steam power is way more complicated than you might imagine. So I suspect it is possible there is no easy way to vent it while still maintaining acceptable forward motion. It is also possible they just liked the idea of going fast.

AnIdiotOnTheNet 8y ago
Most things people don't have experience with are much more complicated than they imagine. It is a valuable concept to keep in mind.

userbinator 8y ago

That part didn't really make sense to me either. I believe there's a throttle valve leading to the engines, and there are relief valves to vent excess steam. It might be that those valves aren't meant to operate continuously, however. I suppose a visit to archive.org's collection of old steamship books could yield a definitive answer.

jacobush 8y ago

Maybe they didn't want to let good fuel go to waste.

pjc50 8y ago
Given that they need a certain amount of fuel to cross the Atlantic, this makes sense - I suppose that disposing of it otherwise would run the risk of running out of fuel.

rypskar 8y ago

If I remember correct from reading about this some years ago. They where low on coal and with the rate the fire did burn coal they needed to burn it in the furnace to get as much speed as possible, to get to the harbor before running out of coal.

expertentipp 8y ago
Sounds like an analogy to an economy and how the money in it is borrowed, created, and spent.

nohat 8y ago

According to one theory presented they were simply trying to use up the coal in the smoldering bunker, thereby putting out the fire.

dexen 8y ago

Running out of fuel aside (as mentioned by rypskar), they may have also needed to conserve the boiler feedwater[0]. The boilers need well distilled water to turn into steam without leaving scaly residue all over the place. During normal operations the steam is routed through engines where it expands and cools and eventually through condensers where it condenses back into water to be fed to the boilers back again. If they throttled the engines down, the excess steam would have kept gathering, increasing pressure. They'd need to either lower the coal feed rate - which they did not want - or blow off steam [1]. Ability to blow off steam is a safety measure not meant for regular, extended operations. Think "analogue of nuclear reactor SCRAM". It causes loud release of huge unseemly clouds of steam, but more importantly it causes loss of the valuable distilled water for the boilers. Btw, operations of marine steam powerplants is surprisingly complex and fascinating subject; consider having a look at this WW2-era navy manual [2] if you ever wonder what it takes to run one such at top power or efficiency. [0] https://en.wikipedia.org/wiki/Boiler_feedwater https://en.wikipedia.org/wiki/Boiler_feedwater [1] perhaps they could route some of the steam directly from boilers to condensers, but I don't think typical condenser installations are capable of directly taking in HP steam [2] https://archive.hnsa.org/doc/destroyer/steam/index.htm https://archive.hnsa.org/doc/destroyer/steam/index.htm

magduf 8y ago
Given that all you need to create more distilled water is heat, I'm surprised they didn't have a way of generating distilled water with excess heat from the boiler.
- dexen 8y ago
  Honestly I am speculating here wrt distilled feedwater, essentially just geeking on a subject I happen to enjoy :^) Any ship installation is limited in size, weight, and power, so you carry machines only big enough to produce sufficient supply for normal operations plus a bit of spare capacity. Even if they had a distilling machine(s) on board, they would certainly not be able to supply as much water as they'd be able to boil off in the main boilers. Also, the apparent ease of distillate production is a bit misleading. In fact, it is a bit of an involved subject, with multi-stage processing, and delicate balances of pressures and the occasional thorough cleaning. At least in the submarine world[1], that is... Basically you want to heat up the water only as much as you need to, but later on recover as much as possible of the heat from both the distillate and the condensed discharge. This is helped greatly by maintaining proper pressures at different stages. Otherwise you'd be running exceptionally inefficient process, and at scale & over span of weeks things add up to real numbers. [1] https://archive.hnsa.org/doc/fleetsub/still/index.htm https://archive.hnsa.org/doc/fleetsub/still/index.htm