Extended Rudder for Airboat

I made an extended rudder for the Airboat. The rudder now is also in the water like a normal boat rudder. So the Airboat is more stable on the straight and also turns better.
I know, that this kind of rudder and also stabilization fins are not in the Intention of an Airboat but - hey - if it works - on the water at least.

https://youtu.be/UT9wtrCCW7Y