Rudder Spacing From the Hull ??
 

I know this isn't the typical question on here, but I'm sure someone will know the answer and why.

Are there any advantage or disadvantage to keeping the rudder as close to the bottom of the hull as possible. Or is it better for there to be a gap on top of the rudder?

Looking for the least drag resistance at higher speeds.

Example in the picture.

Thanks

http://www.38northernbay.com/uploads...94226_orig.jpg