800 times denser than air @ 300 mph = No Prop.

[Lake X Kid]

“By eliminating a propeller, the boat [Ken Warby’s turbojet powered Spirit of Australia] avoided cavitation (bubbles forming around fast‑spinning propellers) and drag, which are major limiting factors in high‑speed watercraft.”

Ken Warby’s SOA boat achieved 317.59 mph world speed record.

It seems, the physics of a propeller (in the water) driven boat will not exceed 300 mph. Because of inducing cavitation and plowing in the drag density of water.

[Lake X Kid]

I know from experience that slalom waterskiing over wakes at over 55 mph and crashing, is skimming and rolling over and over the water's surface until you have dissipated the speed and then sink into the water.

The above data shows us the relative speeds and its density impact of objects (humans and boats) hitting the water's surface at higher speeds.

[Lake X Kid]

Problem Child record run.
Seems to me, even though P.C. has a superb power to weight ratio, the Prop Power & Torque rotation is nearing its limits of plowing in dense water drag and achieving higher speeds and... Not pushing a boat to exceed 300 mph.

[David - WI]

I know from experience that slalom waterskiing over wakes at over 55 mph and crashing, is skimming and rolling over and over the water's surface until you have dissipated the speed and then sink into the water.

The above data shows us the relative speeds and its density impact of objects (humans and boats) hitting the water's surface at higher speeds.

Yes, when you only have to be going about 40 mph to ski on your bare feet... you realize that hitting the water faster than than is going to hurt.

[powerabout]

Try jumping, you got altitude and speed and its perfect usually to stop you in a body length, ouch