We want to show you the arrangement of a boat propeller which can change its angle of attack.

That’s the boat which propeller we are going to assemble.

The propeller consists of a body with cylindrical slots to hold the blades.

Inside the body there is the so called heart of the propeller. It has three grooves for the blades to turn. It is fastened to a push rod which in its turn goes through the propeller. The transmission features a special device which pushes the rod thus turning the blades.

The body’s cover, the view on the inside. It also has cylindrical slots which hold the blades.

This is one of the blades of the propeller. It is rather heavy with a weight of close to 100 kg. By the way, it is relatively small. Costa Concordia for example has blades which are six times as big.

The blades are installed into the grooves of the propeller’s body. As you see, the blade has grooves too. Also, it has a pin with a block on which slips in the slot of the propeller’s heart when the blades are turning.

All that is made of brass, by the way.

One of the blocks. Each block is numbered according to its blade.

This is how it looks when assembled (we put a thick layer of lubricant on it).

It is difficult to install the first two blades and the construction looks like a puzzle. Besides, the bigger the propeller, the more difficult it is to work with it.

The third blade has been installed.

After the propeller has been assembled, you have to pump some thick lubricant into it. It is made with a special high pressure pump with a pneumatic actuator.

Into this propeller, we have pumped about 18 kg of the lubricant. As soon as you see it coming from every crack, turn the pump off!

Thank you for your attention.