uConventional Propellers
•Cavitation is Usually A Limit Above 30 Knots
•External Shaft & Appendages Add High Speed Drag
uWaterjets
•Good For Higher Speeds - No Appendage Drag
•Costly, Heavy, Requires Lots Of Space Aft
uSurface Piercing Propellers
•Potentially Most Efficient At High Speeds
•Lower Cost, Also No Appendage Drag
•Engine Matching At Hump (Getting On To Plane) Requires
Deep Gear Reduction
uAir Propellers For Amphibious Service