… is the U.S. Navy.

Jan 10, 2013 – Navy Sub Goes Bump in the Night and Loses Its Periscope

The U. S. Navy's nuclear submarine USS Jacksonville was damaged early Thursday in the Persian Gulf when one of its two periscopes was struck by an unidentified vessel.

No one was hurt in the early morning incident and the submarine's nuclear reactor did not suffer any damage.

According to a statement from U.S. Naval Forces Central Command, the Los Angeles-class submarine "struck a vessel while operating in the Persian Gulf Jan. 10 at approximately 5 a.m. local time."

The submarine "then surfaced from periscope depth to ascertain if there was any damage to the unidentified vessel. …"

Aug 12 2012 – US Navy ship collides with oil tanker in Gulf

An oil tanker collided with a U.S. Navy destroyer near the Strait of Hormuz on Sunday but no one was hurt and shipping traffic in the waterway, through which 40 percent of the world's seaborne oil exports pass, was not affected, officials said.

…
The collision nevertheless left a gaping hole in the starboard side of USS Porter, a guided-missile destroyer suffered, but no one was injured on either vessel, the U.S. Navy said in a statement. The collision with the Panamanian-flagged bulk oil tanker M/V Otowasan occurred at approximately 1 a.m. local time.

March 20, 2009 – 2 Navy Vessels Collide in Strait of Hormuz

A nuclear-powered United States submarine collided with a Navy warship early Friday in the Strait of Hormuz, the narrow passage through which much of the world’s oil must pass on its way to market, the Navy announced.

Both ships were damaged in the crash, and 15 sailors on board the submarine, the Hartford, were slightly injured, according to the Fifth Fleet, which is based in Bahrain. A spokesman for the fleet, Lt. Nate Christensen, said none of the sailors needed medical evacuation and all were back on duty.

The other vessel, the New Orleans, an amphibious transport dock with 1,000 on board, ruptured its fuel tanks and spilled 25,000 gallons of fuel, he said.

The submarine was submerged, Lieutenant Christensen said, and the vessels were headed to port around 1 a.m. when the collision occurred. The fleet reported that there was no damage to the submarine’s nuclear reactor, and that both ships were able to return to port under their own power.

Jan 9, 2007 – U.S. Navy Submarine, Merchant Vessel Collide in Strait of Hormuz

No U.S. Sailors or merchant crew were injured when a U.S. Navy submarine and a commercial cargo vessel collided in the Strait of Hormuz on Jan. 8.

The collision between USS Newport News (SSN 750) and the Japanese-flagged motor vessel Mogamigawa occurred at approximately 10:15 p.m. (local time) in the Strait of Hormuz while the submarine was transiting submerged.

Sep 5 2005 – No Injuries as U.S. Submarine and Merchant Vessel Collide

No Sailors or merchant seamen were injured when a U.S. Navy submarine and a commercial cargo vessel collided in the Persian Gulf Sept. 5.

The collision between USS Philadelphia (SSN 690) and the Turkish-flagged M/V Yaso Aysen occurred at approximately 2:00 a.m. local time while the submarine was conducting surfaced operations as it transited to Bahrain for a scheduled port visit.

Note that the Strait of Hormuz is largely territorial water of Iran and Oman. While free "innocent passage" is allowed through such waters there are certain conditions for such. In the relevant part II of the UN Convention of the Law of The Sea Article 20 demands for Submarines and other underwater vehicles:

In the territorial sea, submarines and other underwater vehicles are required to navigate on the surface and to show their flag.

The submerged passing of the Strait by U.S. Navy submarines is not only against the UNCLOS demands but, as the cases above expose, a serious danger to regular ship traffic and the environment.