i only know that the Germans did build their BBs and Cruisers with Diesel Engines which gave them a much biger range and also a biger speed. The Spee had a range of about 20'000 sm, and the Sharnhorst a speed of about 32 kts. I dont know exactly how many British ships did run on Diesel but i would expect that after the WW I experiense they would have converted them to Disel as well.

Yes a well maintainde Diselengine won't produce smoke when running. It can happen when starting or Accelerating the Engine that it will produce Blacksmoke doe to the higher Oil burning.

Wrong!!!! Only the panzerschiffe "pocket battleships" (Graf Spee, Scheer, and Deutschland/Lutzow) used diesels and had a very long range. Not sure about the light cruisers, but the Hipper class cruisers, Scharnhorst class and Bismarck class BBs all used oil fired turbines. Furthermore the Hipper class had machinery problems and never were well suited for commerce raiding.

As far as DDs and the Torpedoboots (like small DDs) they also used oil fired steam turbines, the schnellboots used diesels though and were fine vessels. :know:

Exactly. Subs usually accelerate and hold a constant RPM. But to add to the explanation:

Fuel-oil isn't diesel. Diesel isn't fuel-oil.

Surface ships tend to burn fuel-oil, even in this day and age. Diesel actually takes quite a bit of refining in comparison to fuel-oil (which is basicically 50% diesel, and 50% sweet-light crude). Subs burned diesel because it has greater energy density and space on a sub is very premium.

To add some interesting information about coal ships:
between 1939 and 1945 many of merchants and passenger liner used coal fired boilers, and some of these ship literally blowed up when hit by torpedo, a good hit in the coal stock compartment easily ignite greater explosion because of coal dust filled the air acting as gas.