[Hermes37]

A human in flat stable freefall reaches around 144 feet per second.
This is about 120MPH
200+ MPH is possible if U go into a head down dive.
A penny in freefall will go thru a car if it hits it.
A bullet in freefall will approach the same speed going down that it had on the way up. (just as deadly)

A heavy metal object with a small cross section relative to the direction of travel could easily fall through water fast enough to stick upright.

Due to it's shape, it would be nearly impossible for it NOT to be straight upright (or exactly upside-down).

[GhostSoldier]

Thanks for the responses.

My original point was that 400 mph through 'water' seemed too high...

Think so?