Most Impressive Interwar Ship (Civil or Military)

[Guest]

The Lexington/Saratoga* for showing with the CV truely could be. As for unimpressive ships. Any of the treaty cruisers for howing what a warship should not be.

*Its not on the list but IMO the prettiest warship built in the period between the wars was Graf Spee. So sue me.

You are duly sued. I think any German warship built after them were prettier.

[RNfanDan]

The Normandie suffered from what constructors call "torsional vibration".

The North Carolina class also had this problem, again one that was never really solved.

Not to take this off-topic, but wasn't North Carolina's "skeg tunnel" stern construction at least partly to blame for the vibration problem? IIRC, the next class shared this, until their inner propellors were changed to a different style.

[JH]

Personally I would say SS Normandie because of her sleek lines and her speed, her interiors are to match her elagance and a true feat of engenering.


JH

[chuck]

The Normandie suffered from what constructors call "torsional vibration".

The North Carolina class also had this problem, again one that was never really solved.

Not to take this off-topic, but wasn't North Carolina's "skeg tunnel" stern construction at least partly to blame for the vibration problem? IIRC, the next class shared this, until their inner propellors were changed to a different style.

All sorts of things combined to make them vibration prone: Stiffness of the stern, rotational speed of the props, the sheet of turbulent water shed by the trailing edge of the skegs, etc. Many different propeller modifications were tried on the North Carlina, including shaving down the tips of existing propellers. Some fixes shifted vibration problem from one speed range to another. None solved it completely. In the end it was decided that a major structural strengthening of stern structure was the only complete solution. But there was no time to reconstruct her stern during the war.

[Foeth]

It's a bad hull and that you cannot fix, only try to reduce the symptoms.

[Walt]

I have to vote Normandie,,

[shiplover]

I vote for Normandie ! Could Trumpeter or else make 1/350 kits SS Normandie;Queen Mary;Rex;Bremen;United States;... ??? !!!

[Jack Ray]

Shiplover wrote:

I vote for Normandie ! Could Trumpeter or else make 1/350 kits SS Normandie;Queen Mary;Rex;Bremen;United States;... ??? !!!

And 1/700 of course!

Jack

[Guest]

I vote for Normandie ! Could Trumpeter or else make 1/350 kits SS Normandie;Queen Mary;Rex;Bremen;United States;... ??? !!!

To my knowledge trumpeter hasn't made anything civilian yet.

[Lesforan]

Now, that's a tough one to answer.

By "most impressive", I assume you mean a subjective "wow" factor.
I had to vote for the Lexington-class CVs. These were clearly impressive ships in an era of impressive innovations, but so were the others listed.
As was pointed out, this was the age of Modernism...it even included operational flying aircraft carriers, for Pete's sake!

Like the British and Japanese big carriers, these were recycled battlecruisers, so maybe some points will have to be shaved for that fact.

The Hood is widely regarded to this day to be the most impressive ship of the period, and perhaps rightly so. How to compare superliners with Japanese destroyers? A comparision with the French Fantastique-class
destroyers would be more fair.

I would have to take issue with what has been said here about turbo-electric drive. This was first tried on the USS Jupiter before she was converted to the USS Langley. It was a good solution for a problem of the era: finding a way to reconcile the high-rpm nature of the early steam turbines with the desirable lower-rpm screw rotation, in a time before gear-cutting technology made geared turbine plants practical. A significant advantage of electric drive was that layout of boiler rooms/ engine rooms could be better compartmentalized against damage. Also, by locating the generators remotely from the drive motors, shorter shaft runs were made possible.

Also, I would question the statement that turbo-electric drive was abandoned for major ships after the Normandie. The liner Canberra, for one, used it. It is also commonly used in a diesel-electric variant for smaller craft such as towboats and conventional subs.

Vibration should not be an inherent problem with electric drive. In fact, vibration should be less with this drive system than any other. This is because vibration can often be traced to flexing in long propellor shafts, or any deviation from being perfectly true. Either problem will be magnified by shaft length. The relative small size of electric drive motors allows them to be mounted farther aft in the hull, allowing for shorter shafts.

Finally, if the drive system is mounted in an unconventional manner, as in podded drive units or lateral thrusters, electric drive is the most practical method. Just as a steam turbine doesn't care if it is being supplied from a conventional boiler or a nuclear reactor, an electric motor works equally well regardless of what type of engine powers its generator.

[Werner]

The interwar propaganda I have seen (1920s-30s Popular Science down at the library is a good source) show the US as you might a typical small power, with flotillas of subs, plane-carrying subs, torpedo boats, and aircraft (both high and low altitude) replacing the ship in the next war.

For a few years airships were treated like the next dreadnoughts.

It's clear those thinking at the time saw a purely defensive war, keeping the next Emperor Napoleon, von Moltke or William Howe off American soil.

The greatest ads are (in my mind) the cowboy with a tommy-gun herding cattle (implied as a latter day Minuteman).

[Guest]

N
Also, I would question the statement that turbo-electric drive was abandoned for major ships after the Normandie. The liner Canberra, for one, used it. It is also commonly used in a diesel-electric variant for smaller craft such as towboats and conventional subs.

Vibration should not be an inherent problem with electric drive. In fact, vibration should be less with this drive system than any other. This is because vibration can often be traced to flexing in long propellor shafts, or any deviation from being perfectly true. Either problem will be magnified by shaft length. The relative small size of electric drive motors allows them to be mounted farther aft in the hull, allowing for shorter shafts.

The improved compartmentalization supposedly offered by turbo electric power is deceptive. You still need boiler compartments and turbine compartments each pierced with steam ducts. They still need to be at least the same sized. The gear box of the normal steam turbine is now replaced with a dynamo. You still need an engine room connect via shaft alley to the outside. Except instead of the turbine room, a turbo-electric ship could conceivably have a separate motor room. The only way to improve compartmentalization is to divide the turbine and the motor, but in that case your are not improving compartmentalization. You are merely spreading each set of machinery into more compartments. But each of the original boiler and turbine compartments would still need to be about the same sized. So compartmentalization is still the same as before, except hits on more compartments can potential bring about the immobilization of the machinery.

On the minus side, turbo electric drive involve dangerously high voltage, tremendous potential for deadly arcing and other extremely volatile hazards. The shortening of the shaft is not in practice realized. In most cases serious vibration was not caused by long shafts, but by in appropriate degree of natural hull stiffness. The only real major advantage of turbo electric drive is it removes the need for an astern turbine and it allows the ship to go astern at maximum engine output.

[Werner]

I thought the idea was steam and turbogenerators were unitary, so they could be shut down when not needed for efficiency's sake. The electric motors were an integral part of the shafting, too, and were not multi staged with low, intermediate, high pressure, reversing stages and cruising turbine, all to be clutched into the drive shaft, sometimes with colossal gear boxes and complicated power/efficiency formulas.

Modern railroads run on the same principle. If you need more power, add more locomotives, which are after all diesel generators with motors down in the trucks where as few moving parts as possible are needed for energy transfer.

Of course, the control and safety features of the US ships appear to not have been properly shock proofed before late 1942.

Clearly they were quite satisfactory in railroad use, where steam was all but extinct by 1960. Cruise ships, too, went from steam to diesel electric rather quickly in the same period. Except for warships and airplanes, the turbine seems to be down on it's luck as a transportation power source.

Near my house is the Illinois Railway Museum, which features a Union Pacific turbine locomotive from about 1950. It had a normal electric-looking engine, then it had the steam/turbine car and a caboose for the fuel oil. Although state of the art, it could not match diesels of the period. It's too bad, too, because the fuel could have been oil, compressed gas, powdered coal, just about anything. Food for thought in these times.

[chuck]

Railroads are poor comparisons. 1. Steam locomotive used reciprocating engines, not turbines. 2. Locomotives require frequent speed changes and often minute speed adjustments. 3. Locomotives benefits from increased weight. Steam locomotives are too light and runs out of traction before they run out of power.

[chuck]

I thought the idea was steam and turbogenerators were unitary, so they could be shut down when not needed for efficiency's sake. The electric motors were an integral part of the shafting, too, and were not multi staged with low, intermediate, high pressure, reversing stages and cruising turbine, all to be clutched into the drive shaft, sometimes with colossal gear boxes and complicated power/efficiency formulas.

I don't think it is possible to make electric motors integral to the shafting. It must be possible to disconnect the motor from the propeller shaft by the use of a clutch in order to allow the propeller to windmill freely in water flow should malfunctions causes the motor to seize. Otherwise the windmilling of the propeller will demolish the motor.

If you have turbo-electric mechanism, the entire train would consist of boiler, turbine, dynamo and motor. There would be almost no reason for the turbine set to be unitized with the motor since they are only connected by bus bars. Unitizing them would remove the possibility of, for example, turning off one set of turbine for maintenance while continueing to turn its shaft using power from another turbine.

Yes, turbines for turbo-electric drive would be simpler than normal marine turbines because they can turn at a constant optimal velocity unconstrained by required prop RPM and available gearing ratio, and they can turn in only one direction. However, this advantage is offset by the need for separate electric dynamo and motor, dangerously high voltage, and the problem with high voltage and salt water in case of flooding.

[Werner]

In the book about rebuilding the Pearl Harbor Fleet, there is an interesting picture of LCDR Rickover standing over the embedded DC motors on one of the battleships. They were surprisingly small.

[chuck]

You'd be quite surprised how small normal marine steam turbine have gotten by WWII. A 20,000 shp turbine with reverse stage and cruising stage will easily fit a kid's bedroom or a large walk-in closet.

A matching single reduction gear box will also fit into walk-in closet.

[Werner]

Those 35,000 horsepower turbo pressure fired disasters aboard the Knox took up considerably more room. Perhaps they should have consulted some children.

[Guest]

Those 35,000 horsepower turbo pressure fired disasters aboard the Knox took up considerably more room. Perhaps they should have consulted some children.

Pressure firing has nothing to do with the turbine. It's a boiler thing.

[Guest]

You should see the 20,000 hp turbine in the HMS Belfast, with its casing open.