Very Dangerous Still - USS Houston (SSN-713)

Inadequate (by today's standards) senors to detect surface shipping and limited communications capabilities placed low-profile, early submarines at risk of collision even when on the water's surface. For submerged subs, collision risk was very dicey. Much has changed, but one hazard persists.
Submarines are exceedingly cryptic, murky, and enigmatic. In fact, discussion of their ordinary maneuvering entails terminology that limits the general public's comprehension to about 22%, even before requisite secrecy considerations.

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EXAMPLES

True submariners know what a submarine has done if it broaches (see the 14th of 18 definitions for broach).

Broach (submarine) Submarines operating submerged are said to have broached the surface when a portion of the ship (such as the sail, bow, or screw) other than a mast or antenna comes out of the water.

See? Only 22% of the public would have guessed that, although the definition is public information.

If the sea suction forces are greater than the ballast and planes authority, the submarine will broach the free surface increasing detection risk by several orders of magnitude. source

It had always been that way. The following historical incidents are examplary only, and hardly intended to be exhaustive:

For all its innovations, the USS Holland [SS-1] had at least one major flaw; lack of vision when submerged. The submarine had to broach the surface so the crew could look out through windows in the conning tower. Broaching deprived the Holland of oneof the submarine's greatest advantages, stealth. source

The U.S. submarine Stickleback (SS 415) received severe damage on May 28, 1958, when she collided with her escort ship, Silverstein (DE 534) during exercises off Pearl Harbor, Hawaii. During the course of the maneuvers, the Stickleback had broached and the Silverstein struck her amidships between the forward battery room and the control room. Rescue operations recovered all of the crew and the sub sank late on may 29, despite tremendous efforts to keep her afloat. source

Before the problem could be corrected, Houston [(SSN-713)] had attained a down-angle in excess of 30 degrees and her screw broached the surface while still turning at a high rpm. The extreme angle triggered an emergency shutdown of the reactor plant to prevent damage. source

..once broached a boat tends to wallow their like a beached whale...source

Submarines are always silent and strange.