Propellers

The amount of propellers depends on the ship.

3 propellers
The RMS Olympic, RMS Titanic, and the HMHS Britannic have 3 propellers. The propellers on Britannic destroyed 2 boats during the sinking, and like 30 people with it.

2 propellers
The RMS Empress of Ireland has 2 propellers.

4 propellers
The RMS Lusitania has 4 propellers.