I have two airboats that I have powered by MDS .18's. One is a Swamp Buggy by Dumas, the other is my own design.
The Swamp Buggy Hull is 28 x 10 x ~3.
The KM2 hull is 25 x 10 x 1.5".
Check out the thread "My latest Project" to see the KM2. There is also an older thread that I have pics of the SB posted. You can also go to my picture albums to see them, but not as detailed as the pics posted on RCU.
http://groups.msn.com/K-MotionRCAero-Marine/homepage
click on the Pictures link