Hey Raiki! nice to finally find someone from my own city! I reckon your ducted fan found work well of you got the right hull. Think about it: what is an airboat? many airboats do upwards of 35mph.
what i really would love to see is an AMT 20lb-thrust turbine on a boat!

now that, would definately heat up the water (but if it rolled, you could say goodbye to A$5000!)