Building a more-efficient water propeller? I enjoy making Power Functions-controlled boats to race (in water) in various LEGO convention competitions (which require 100% genuine LEGO pieces).

Usually, these boats end up being paddle boats, because of how inefficient all the LEGO propellers are. Supposedly Propeller 2 Blade Twisted (4745) is actually the most-efficiently shaped LEGO water propeller.



There are a number of problems with this propeller.


The blade are thick.
There is no good way to attack an axle to it.
The shape of the blades is sub-optimal.
It's on the small side.


Is there a way to build a more-efficient one, out of several pieces?
The LEGO RC boat by Slewentogzz claims to have a top speed of 3 km/h, it uses a custom propellor built out of Technic parts.

The actual rudder parts appear to be Technic Panels #87080 and #87086. These panels are very common and are available in over 60 sets.

There are two more parts in a similar design (#64683 and #64391, they are one stud longer each so you can make a slightly larger propellor.







Images: Slewentogzz Lego Creations

Video: "Lego RC Boat with custom built propeller (3,0 km/h!)"