[Rudder]

It seems unlikely that an object could drop through three miles of ocean, and anchor itself on the bottom.

As opposed to what other outcome?

Heavy, steel, iron, etc., etc. objects can reach speeds over 400 mph if they descend in sufficiently deep water. (Read about the SSNThresher.)

A massive, steel and iron (foundation or step for the anntena on the ship) assembly breaks loose from its ship and impales itelf solidly in the bottom.

Not an unlikely event--right?

[GhostSoldier]

Heavy, steel, iron, etc., etc. objects can reach speeds over 400 mph if they descend in sufficiently deep water

400 MPH. You sure? That sounds quite a bit faster than the free fall rate through the air (terminal velocity...I think is in the neighborhood of 286 ft per second).