in most cases (with a few exceptions), you want to choose the engine that has the most horsepower.   Also, your ship type should match your engine type (with exceptions as well).

So for your destroyer, you probably want to use the Destroyer I Heavy engine (if i remembered correctly)

no one is stupid good thing you asked we noobs all make mistakes. btw the high lvl do also, lol.

The engine with the most  BHP. Or if two engines have the same BHP, the one of the two with the highest Overheat ratio %.

Pretty much the highest engine # for the ship tier. Except Alaska/Guam/Sodak use the 165k BHP CV engine and the Iowa/Nebraska uses the 233k BHP USN BB Engine VII not the 189k BHP USN BB Engine VIII <--- Monty Engine

Just to make you feel better, i will explain my fail.

Largest ship: BB5 Montana

I set up an escort but I put a sub engine on my escort so it wouldnt cross me. Little did I remember. I unset it as escort and started driving it. I went very slowly....

Rofl. But it will be no where near your monty to do any good! It is going to go 1 knot!

Hello there. I Dnt have any fance technical answer for you, but i got an pcl texas, and there is two engines with the same hps for it. cl 3 (if im not mistaken) and dd3 (sorry again, lol). The dd engine, with no armor on the ship, same crew and engine weight 330 t, gives me 24 to 30 knots of speed, while the cl engine, same crew, no armor and 660 t (double weight), gives me 24 to 33 knots. Is the tipe of engine also afects the speed? Or im getting crazy over here?

The DD Engine III (I assume this is the one you are talking about) has an OH % of 48 meaning that in full OH your ship moves 48% faster than it's normal speed while the CL Engine II (again assuming) has an OH of 66% so 66% faster in full OH than at normal speed.