A comedy of errors caused by a lack of even “basic skills such as seamanship and navigation” caused two deadly Navy destroyer crashes in the Pacific this summer, a damning new report has found.

The USS Fitzgerald slammed into the merchant ship ACX Crystal off the coast of Japan on June 17, killing seven US sailors in the process. The USS John McCain smacked into the oil tanker Alnic MC near Singapore on Aug. 20, leaving 10 sailors dead.

The incidents were so mind-boggling that the Navy considered whether the boat’s steering controls had been hacked — but a report issued Thursday by the Navy’s US Fleet Forces Command found it was mostly just old-fashioned incompetence.

“In each incident, there were fundamental failures to responsibly plan, prepare and execute ship activities to avoid undue operational risk,” according to the report, which also looked at two other incidents in the Navy’s 7th Fleet.

The Fitzgerald’s crash was due to a “compilation of failures by leadership and watchstanders,” the report states.

Lookout crews “were inattentive, disengaged in developments on the Bridge, and unaware of several nearby vessels,” and they “failed to visually differentiate between two vessels in close proximity” while “attempting to cross a highly congested sea lane at night.”

Once crews realized they were on a collision course, one officer began barking steering orders at another, who “‘froze’ in the moment,” the report states. Then both officers began shouting instructions to the helm.

Thirty seconds before impact, a crew member at the helm accelerated and made a hard turn away from the ACX Crystal — but it was too late, and the Fitzgerald was “increasing speed by the time of impact” as a result, the report states.

The USS McCain’s wreck was caused by an equally disturbing series of failures.

The person at the helm was not competent to handle steering and acceleration at the same time, so crews split the steering and throttle among two different drivers.

But they accidentally gave steering control to the wrong person, leading the sailor expecting control to believe steering systems had failed.

Crews then scrambled to fix the mistake, transferring steering “among various controlling stations four times within the two minutes leading up to the collision,” according to the report.

So sailors tried to slow the ship down by letting up on the gas. But crew members accidentally “decoupled” the ship’s two engines — essentially creating a separate gas pedal for each one.

When the seaman at the helm backed off the throttle, it only slowed one engine while the other continued to rev — effectively accelerating the boat’s turn into the Alnic MC.

A culture of hubris fueled the incidents, the report found.

“In each of the four mishaps there were decisions at headquarters that stemmed from a culturally engrained ‘can do’ attitude, and an unrecognized accumulation of risk that resulted in ships not ready to safely operate at sea,” according to the report, titled “Comprehensive Review of Recent Surface Force Incidents.”

The report is the latest in a series of blows suffered by the Navy’s 7th Fleet, which is responsible for monitoring the Pacific including North Korea. Sailors aboard the fleet’s USS Shiloh described that ship as a “floating prison,” according to a recent report.

Crew complained that they were afraid to ask questions, lest they be demeaned for their lack of knowledge, and complained it created a culture of unpreparedness.

“I just pray we never have to shoot down a missile from North Korea, because then our ineffectiveness will really show,” one dejected sailor wrote.

The Navy has said it would discipline crew members responsible for the crashes and also dismissed 7th Fleet commander Vice Adm. Joseph Aucoin following the incidents “due to a loss of confidence in his ability to command.”