The drive is not actually the most interesting part of the whole design. It is merely a stripped down cable drive like we've seen with H2O Pro-ped
There are two interesting features of the SBK that really tweak my brain - one is the tilt a bike feature, and they tell you about it. It's pretty unique and most aquabikes don't do it.
The other is that they adapt pontoon geometry to bike geometry. Have a look at the pontoon page.
Notice that the pontoon hull for the 26" MTB has a completely different bow volume and taper to the city bike pontoons? Now THAT's clever.
First to design a wave-certified dropper post - 3, 2, 1...go!