Ladies and Gentlemen, may I bring it to your kind attention that the rotation of propellers and the way they are viewed indeed varies.
To date, propellers are the most efficient way of moving a vessel through the water, by converting the shaft horse power into thrust.
Please see the pictures I have included below.
One of these photographs (see picture A) is from the early 1900’s, this shows an early Cruiser. The propellers here are rotating inboard. The blades of the propeller are long and narrow.
You will see from the photograph (see picture B) from around 1937 shows a Cruiser with ‘quad’ propellers and the forward propeller is turning outboard. This propeller shape has changed as you will see. It is what is classed as a wide tipped blade. (Elliptical)
The next photograph, (see picture C) shows a modern ship, propellers are in ‘pods’. If you note that the propellers on this vessel turn inboard, and, also the propellers’ face forward to the bow of the ship, this in turn gives more efficiency from the electric drive motors in the pods.
The last photograph I have included is that of The Turbinia. (See picture D). Close examination of this, will show you that there is not one propeller on the shaft, but, there are several – of all varying designs which are again, turning outboard.
All the above are viewed from the stern, looking towards the bow.
From this we can deduct that the direction to which a propeller rotates depends upon which vessel it is fitted to and what the vessel is designed to do.
During the period of the war years a lot of our British multi-propellered small inshore vessels such as MTBs (motor torpedo boats) the propellers rotated the same way on a lot of them. This was because there was quite a shortage of reverse gear boxes.