WASHINGTON, D.C. (WVEC) -- The Navy's top admiral said Tuesday there are any number of possible explanations for the deadly collisions of the destroyers USS Fitzgerald and USS McCain, which killed 17 sailors.

Frequent extended deployments. Delayed maintenance. Gaps in training. Continual budget constraints. Not enough ships in the fleet.

Chief of Naval Operations Admiral John Richardson told the Senate Armed Services Committee that his forces have ben stretched thin.

"Our ships have been run hard," he said. "They are spending more time in maintenance and that pressurizes the operational time."

Richardson added, a failure of command throughout the service was the main contributing factor, telling lawmakers, "I own this."

Arizona Senator John McCain said one immediate answer could be, stop forcing sailors to work 100-hour work-weeks.

"When someone is working 100 hours a week, over a period of time, they're going to make mistakes," he said. "Any manager can tell you that."

Virginia Senator Tim Kaine likened this investigation to the on he initiate as governor into the Virginia Teach massacre.

"The only thing we can do, sadly, is try to learn everything we can from what caused them to die so we can reduce the chance it happens to anybody else," he said.

The CNO downplayed questions about possible cyber sabotage. He said he'd gotten a report on that just this morning, and he said there is "no evidence of tampering."

Monday, Two senior Navy officers were fired due to a "loss of confidence in their ability to command," following the crashes.