Propellers are made of copper, bronze, cupronickel or steel. There are various reasons why propellers have anything from to 2-6 propeller blades. A 2 blade shaft propeller is ideal for a racing sail boat, giving high speed and minimal drag. The most common propellers, are 3 blades for speed and 4 blades for thrust, mostly used in yachts. Container ships will often have 5-6 bladed propellers however, offering fuel economy and holding power in rough seas.