The survivors of the sinking say that the lights stayed on-even as the ship began its final plunge. Is this true? Once the boilers were submerged, how did the engineers keep the generators running? Not to mention the massive numbers of short circuits as the water filled the lower decks. Did each deck have its own circuit breakers? And, did they have emergency generators on the upper decks?
Here is a quote from a message board that contains much of what I was seeking.
The site is Encyclopedia-Titanica. Read the whole post which is 4 down in the thread. I see some other promising sources. I wanted this one posted now.
I found later in the thread what I was looking for. The current was DC, which is important in that it wouldn’t conduct in water as well as AC. DC would be more likely to go through the wire than the water. AC can travel vast distances which DC doesn’t.
This example shows how little DC current flows in water when a wire can be the pathway instead. Think of your car battery and if it gets wet between the terminals it slowly discharges the battery. The battery quickly discharges if the terminals get shorted with metal. The metal might even weld to the terminal. The battery can discharge in this situation fast enough to melt or explode the battery.
I suspect they also may have had a battery bank in the Titanic that could provide light if the dynamos died.
One thing else I need to add. The Titanic sunk bow first, The emergency dynamos were in a watertight room between the two propeller shafts.
Water may put out the fires in the boilers, but it doesn’t cool the water already in the boiler very quickly. Nearly all of the heating area of the boiler was in internal flues, or “fire tubes” and the outside of the boilers were normally insulated (“lagged”) for efficiency as well as the comfort (such as it was) of the crew that had to work around them. The main boilers (*) were sized to run the propulsion engines so if the only load was the dynamo engines there would be enough superheated water to run them for a very long time.
- There was also usually a smaller “donkey” boiler for use in port, or for putting out a wireless distress call if the main boilers failed. A concept echoed in the APUs on modern airliners.
ETA: spelling fixes
Is ralph124c around? It’s been a day and a half. Is the question answered to your satisfaction?
The OP seems to presume that generators were always needed. My guess is that the emergency lights lasted at least a few hours on batteries.