Hi Chris
I near missed that little dig !!!!
But in scale up speed I think my mates Spearfish on or over the 55 Knots.
It's only on 4S and the motor (3648-1450kv) is rated to 6S !!!!
On 4S 5800mah Lipo
Prop 2 blade 38mm 1.4 pitch draws 60Amps speed 36kph.
Prop 2 blade 40mm 1.4 pitch 55Amps 37kph.
Prop 3 blade 37mm 1.4 pitch 60Amps 37kph.
Have you decided to sell me the Spearfish kit or you going to build it ???
Harry