Powering a Ship

Yup, little power plants. Most likely small generators, fueled by diesel or gas. Even sailing ships usually have small motors, for emergencies, wind dying down, etc. No doubt proper boat people will be along shortly with detailed responses. As for 'whole cruise ships', yes, it takes a whole lot of power, so they have bigger engines. And huge quantities of fuel to run them.

Horserider said:

If they're carrying that much fuel, you'd think it would be more likely that cruise ships would explode or catch fire...

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Well they're not moved by oar power.

My husband's family used to own a shrimp boat in the Gulf of Mexico, and he says most boats have a Coleman type stove or propane. He's pretty sure boats like on the Deadliest Catch also cook with propane (but cruise ships obviously don't.)

On smaller boats the lights, etc. run off a battery, attached to an alternator on the diesel engine, just like a car.

Shipboard cooking has changed over the years. On the wooden ships, the ship's stove would be a brazier or an oven fed by wood or charcoal. It needed constant attention to avoid catching the ship aflame, and needed to be extinguished in heavy seas.

In the days of iron ships, fuel was typically coal, and so ships ovens would normally be coal-fired too -- which was also what domestic stoves used at the time. I've also heard of steam ovens, but as far as I could discover they're a modern invention -- I've never heard of a coal-fired ship using one (but someone please post a link if so).

In modern cruise ships fuel is typically diesel, and a natural choice for oven is therefore electric, run from the ship's power-plant. But LPG or propane stoves are also used -- especially if you're not running the generators all the time (e.g. on sailing craft). LPG and propane are useful if you don't lot of other fuel. If you are, it's usually more sensible to use the fuel you carry.

On a nuclear vessel I don't know but I'd expect to see electric ovens. Why carry flammables if you don't need to?

> I doubt they have any little power plants on ships.

They do. The power plant generates electricity and what drives the screws are electric motors. Everything else on the ship is electric.

Here's a blub on a Carnival Cruise ship:

CRUISE SHIP ENGINES
Carnival Pride has diesel-electric machinery, consisting of six Wärtsilä 9L46D diesel engines with a total power of 62,370kW, each connected to an ABB alternator producing electricity to the ship's main electric network at 11KV 60Hz 3 phase.

Power from the main switchboard is supplied to 440V switchboards via three transformers to serve auxiliary machinery and ships services. A separate MG stabilised power system supplies lighting and small consumer needs.

PROPULSION

The propulsion consists of two azimuthing electric Azipod propulsion units, with a power of 17.6MW each. The ship has three 1.91MW tunnel thrusters in the bow. The service speed is 22 knots.

The classification society of Carnival Pride is the Italian RINA, and she sails under the Panama flag.

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-cb

Most people don't understand that Diesel Trains - are propelled by electric motors. The Diesel Engines generate the POWER for the electric motors. Electric motors are incredibly efficient in terms of torque and horsepower. Google up the "Tesla Roadster" for some impressive statistics.

WriteKnight said:

Electric motors are incredibly efficient in terms of torque and horsepower.

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Not to mention the double convenience of transmitting the energy to wherever you want to use it, and being able to store it in non-flammable forms (like batteries and capacitors).

The main problem with electric is the efficiency of energy generation. You normally need to convert chemical energy to mechanical energy, then mechanical energy to electrical energy, then transmit the energy and convert it to whatever other us (lighting, heat, mechanical movement). But we've lived in an energy-rich economy for a long time and we're used to end-to-end conversion rates of 30% or worse.

Some sailing ships have a little wind- or water-driven propellor that provides a trickle charge to electric batteries. Not enough to run an electric oven perhaps, but enough to drive winches and run lights and navigation systems.

Most ships carry a diesel powered generator for auxilliary power needs. Lights, electrical outlets, cooking, electronic equipment,, and everything else that runs on electricity. The size of the generator depends on the power requirements. A cruise ship may have several of these generators, some of them operating as emergency backups.

Horserider said:

If they're carrying that much fuel, you'd think it would be more likely that cruise ships would explode or catch fire...

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Has happened. Although fires on passenger ships often start in cabins or laundry rooms or kitchens rather than in association with the main engines or fuel supplies.

caw

I've also heard of steam ovens, but as far as I could discover they're a modern invention -- I've never heard of a coal-fired ship using one (but someone please post a link if so).

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I read a book by Massie: Castles of Steel which talked about World War 1 naval vessels. At the beginning of WW1, most naval vessels were steam powered, with oil powered vessels being introduced late, and becoming standard by WW2. There was a brief discussion of how such boats were heated: Apparently, the british ships had steam radiators throughout, which just used excess steam from the boiler. The German ones had electric heaters. So it wouldn't surprise me if the cooking (which was not described) was done with similar means on the vessels in question.

Sarpedon said:

I read a book by Massie: Castles of Steel which talked about World War 1 naval vessels. At the beginning of WW1, most naval vessels were steam powered, with oil powered vessels being introduced late, and becoming standard by WW2. There was a brief discussion of how such boats were heated: Apparently, the british ships had steam radiators throughout, which just used excess steam from the boiler. The German ones had electric heaters. So it wouldn't surprise me if the cooking (which was not described) was done with similar means on the vessels in question.

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"Steam powered" would be a misnomer, as some fuel must be used to heat the water into steam. Most likely coal. "Steam-DRIVEN" would be more accurate, no?

Well yes, I thought that went without saying. One could also use wood, but ships prefer the less bulky coal.

Depends on the kind of ship, but most of the boats I deal with have Northern Lights or Onan generators aboard which produce electrical power. Diesel generators are safer, since diesel fuel is substantially less reactive than gasoline, and if you have gasoline units on board (either generator or engine) you'll need to crank the bilge blower for about four or five minutes before starting it up.