Re:lateral plane area and twin rudder

[otaku]

Interestingly, last night i found that on my twin-rudder model, reducing the gap of some 3 feet between the hull and the rudder decreased the resistance. I am not using a single rudder with doubled surface, since i’m designing a twin-rudder ship and want to have the rudders exported as .dxf and other formats.

So, is there something beneficial going on that we aren’t appreciating?