This is White Star Line’s RMS Majestic, formerly Hapag’s Bismarck before WWI. She was one of the most successful transatlantic ocean liners in the history of the trade. This is picture shows her hauled out in Southampton’s floating dry dock. I have seen countless other photos of countless similar vessels all showing the same irregularity: there is clearly smoke coming from her forward funnel indicating that at least some part of her steam plant is online. Of course you want to maintain electrical power, even while in dry dock, but doesn’t all that machinery require cooling water? Unless I’m mistaken the norm for ships of this type and of this era was to have closed-loop systems with steam being condensed (by sea water) and reintroduced to the boilers. How does this occur while out of the water? Even if it’s not a closed loop, with used steam being exhausted up the stacks, wouldn’t boiler water need to be replenished from somewhere? Again, how does this happen if the ship is in dry dock?
They probably attached a small priming pump on the dock to the sea chest of the condenser pump. The spent steam coming from the generator turbine is cooled there by the sea water passing through tubes in the chamber. It’s then pumped back into the feed water system. Up to the DC heater mounted somewhere in the fidley which provides positive head to the feed pump.
That all makes sense, I don’t know why I couldn’t wrap my little head around that. It wouldn’t take much to hook up a couple of big pipes/hoses to the sea chests for various things and supply water. Is this still the practice in dry docks today? I know smaller stuff can take a shore power cable but what about something like a cruise ship with a huge electrical draw?
Ships of that era were typically fitted an auxiliary condenser that used distillate from the main condenser hotwell for cooling as it performed the secondary purpose of feed water heating. Using seawater for cooling is very wasteful of energy, the only reason it is used in the main condenser is because of the tremendous amount of heat needed to condense main engine exhaust.
The reason a boiler is online is so that the ship can make its own electrical power … shore power was not very common in those days. The condensate pumps were either electric or reciprocating steam pumps so the ship could be kept alive on the reduced output of one boiler and not require shore power or shore supplied cooling water. In some cases steam might be supplied to the ship from a shore boiler to keep things warm but in my experience on steamboats in dry docks, we just used shore power until floating again and could start a fire in a boiler to get a generator online and go from there.
Find a heat balance diagram for a steam plant and you will see where condensate is used as a medium to both condense auxiliary steam and for feedwater heating … the idea is to never throw a BTU over the side or up the stack if you don’t have to.
[QUOTE=PaddyWest2012;180938]That all makes sense, I don’t know why I couldn’t wrap my little head around that. It wouldn’t take much to hook up a couple of big pipes/hoses to the sea chests for various things and supply water. Is this still the practice in dry docks today? I know smaller stuff can take a shore power cable but what about something like a cruise ship with a huge electrical draw?[/QUOTE]
Water connections in the dock are generally for firemain and maybe potable…nothing more. The seawater systems go dry for the duration until the dock is flooded again. That’s a good thing; at the five year interval, a lot of valves are being replaced and/or checked. Of course I’m talking about motor ships, but I have drydocked a steam ship and we did not have the ability to operate boilers on the blocks, for the same reason.
A cruise ship in the dry dock will likely not have the same power requirements as it does at sea with an operating plant and a full roster of passengers. The shipyards usually provide their own power for most repair work, and you’ll see those temporary cables and breaker boxes set up and routed where needed.
The navy had a variety of barge mounted equipment including barge mounted boilers to provide aux. steam for ships in the yards or dry-docked. I know a guy that did pretty well buying a steam barge that was surplussed from PSNS in Bremerton. He sold the steam plant to a cereal factory somewhere in the midwest and basically wound up with a free deck barge that had extra tank-age for fuel and water.
[QUOTE=catherder;181014]Water connections in the dock are generally for firemain and maybe potable…nothing more. The seawater systems go dry for the duration until the dock is flooded again. That’s a good thing; at the five year interval, a lot of valves are being replaced and/or checked. Of course I’m talking about motor ships, but I have drydocked a steam ship and we did not have the ability to operate boilers on the blocks, for the same reason.
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In cases where systems that use seawater cooling at sea need to be operated then the S/Y supplies cooling water. The fixed low-pressure CO2 system comes to mind.
In general the yard will provide whatever the owners are willing to pay for, within reason.
Cooling water is typically provided for the Reefer Systems (Provision & Low Pressure CO2 if so equipped) and House A/C (depending on the time of year). This can be taps off the charged firemain or separate lines.
If the they are getting ready to flood the drydock it is not unusual to begin lighting off the boilers beforehand in preparation to bringing the plant online before cooling water is needed.
On motor ships I’ve seen the yard run a line to one of the LT Coolers in order to run a generator. This was done if the yard didn’t have enough shorepower to run ship’s equipment, i.e., cranes or ramps.
