Is a supersonic boat possible?

Assuming supersonic in air: 344 m/s or 669 kts is the target speed.
Assuming standard speed-length ratio of 1.34 in Old English units, and full displacement mode.

Solving for hull length gives 249,254 ft- meaning the hull is 75.97 kilometres long at the waterline.

The vessel's wake will travel about 1.2-1.5 times faster than a large open-ocean tsunami.

 

Holy crap! That's just not possible to use the disp hull then, right?

 

Well, going with a fastferry-like speed/length ratio of 2.0, we can shorten said boat to only 110,890 feet - a mere 33.79 km.

 

It CAN be done

 

Supersonic

WHO CARES? The subject of this thread is Supersonic BOAT. It isn't SUBMARINE. It isn't TORPEDO. "The fastest current water-borne craft of any sort are supercavitating rocket-powered torpedoes" is why the subject is BOAT.

 

How do you get the passengers to the other end of the "boat" in time to get off?
MagLev trains?

 

i'm not so sure bout that, those russian torps do bout 400 km hr is said but hush hush, recently one sunk the koersk if i recall well. boat waterspeed record is and aims a little higher isnt it?

 

The Kursk, you mean? It sunk due to an explosion related to the fuel for the torpedoes.

 

What would the compression of the shock wave do? My impression is that it would be another wave forming source.

 

I don't know what the air to water sound wave refraction ratio is but it seems that while a large part of the energy in the lower 180 degree will be reflected back up a shockwave will form in the water. If the rings in the water are high enough they should be traveling faster that the boat which means that the two will meet somewhere. That could get bumpy.

(even hydrofoild would experience this in some form)

 

What I want to know is a supersonic rowboat feasible...imagine the weight savings in food and drinking water alone on a trans ocean attempt

 

Not really possible, nope

 

I think someone asked how much power it might take....
Spirit of Australia used about 1.88MW to reach 140 m/s, or so Warby's site claims. It weighed 1.6 tonnes. That translates to about 1575 hp/ton at that speed. Warby also claims his J34 can put out 9000hp on full afterburner, or about 5600hp/ton. These boats travel at roughly 0.5 Mach, so quadruple those power figures to get a rough estimate of what a supersonic craft might require. My bets would be on the 8000-12000 hp/ton range.

 

The British, Blue Bird almost made the return high speed run. Until he hit a tiny wave that was from his first pass. It bounched off a rock wall and the boat exploded so completly they never found any body parts. That was around 300 to 400 mph range. A bird farting 1/4 mile away is sure death!

 

Almost. There's an awful lot of "almost" in speed record attempts.
Hitting the water at 140 m/s is much like hitting concrete at 100 m/s. Ask any commercial airline pilot- their training is that if they have to ditch in water, come in as slow and as level as possible; full flap and slat if they can. Skimming the water at +5 degrees is something an airliner (or boat) can handle; impact at -20 degrees simply crushes the front of the vehicle flat in much the same manner as running a Ferrari into a wall at top speed. Kind of hard to manage this safely.