It’s still not clear what initially caused the 2010 sinking of the Majestic Blue, a distant-water tuna boat that went down in waters 3 miles deep and 101 miles off the coast of Fiji, killing the ship’s American captain and its South Korean chief engineer.

However, Honolulu-based Coast Guard officials found that the ship’s practice of leaving watertight doors open allowed flooding throughout the boat.

Furthermore, the U.S.-flagged Majestic Blue’s engineering officers could not speak English and weren’t familiar with emergency procedures — two key factors that hampered the emergency response, according to Coast Guard officials.

Those findings, released Tuesday, come a week after the agency announced fines against boats in the same distant-water tuna fleet as the Majestic Blue for repeatedly using unlicensed foreign nationals to illegally serve as engineers and chief mates on those vessels, instead of the licensed foreign workers pre-vetted by the Coast Guard.

Those fines were levied against a company that did not own the Majestic Blue. However, the Coast Guard in recent days has raised safety concerns about the U.S. fleet of 40 distant-water purse seiners, which harvests tuna in remote Pacific waters under international treaty.

Special exemptions for the fleet allow all but the ship’s captain to be foreign nationals. Meanwhile, Coast Guard officials are calling for stricter inspections of these industrial-sized boats, including mandatory annual drydock inspections to ensure that the boats’ hulls are secure.

Months before the Majestic Blue sank, one of its previous American captains alleged mutiny and abuse by the boat’s officers and crews, who were all foreign nationals, in a suit against the ship’s owner.

Various accidents have left 19 crew members dead aboard these distant-water purse seiners in the past eight years, and in 2012 the Coast Guard flagged the rate of deaths aboard these vessels as four times worse than the national rate.

The Majestic Blue was built in 1972 in Spain. The Coast Guard report on its sinking states that on June 14, 2010, when an alarm on the bridge sounded, the boat’s second engineer found water shooting to the ceiling in a rudder room — but he did not shut a watertight door there when he left.

When he and two other engineers returned about five minutes later, they were unable to seal that door because the pressure from the water had grown too strong, the report stated.

The boat’s crew abandoned ship minutes later, but the captain, who was heard saying, "This is my responsibility. I want to know what happened," returned to the bridge with the chief engineer, according to the report. The boat capsized and sank with the two aboard minutes later. The surviving 22 crew members were rescued about eight hours later by another purse seiner in the fleet, the report said.

The vessel’s captain was Florida resident David Hill, a licensed ship master, according to court documents in a wrongful death lawsuit brought by Hill’s widow, Amy, against the boat’s owner, Guam-based Majestic Blue Fisheries LLC and South Korean tuna company Dongwon.

The boat’s previous captain, Thomas Ridenour, contends the maintenance done on the Majestic Blue just months earlier in a Longsheng, China, shipyard was poorly done and likely would not pass a Coast Guard inspection, according to those court documents.

The suit further claims that Dongwon, which owns the U.S. tuna brand StarKist, paid all Majestic employees, and that they "routinely and deliberately ignored the orders of Captain Hill" while reporting directly to Dongwon officials.

In a separate 2010 suit, another previous Majestic Blue captain, Douglas Pine, alleged that the ship’s officers repeatedly assaulted him and defied his orders — to the point that Pine radioed the Coast Guard for help, left the boat when it docked and claimed mutiny against the crew. That court action, in which Majestic Blue and Pine sued each other, was dismissed voluntarily in 2011.

Dongwon officials could not be reached for comment last week. The company has stated that it did nothing wrong in the Hill case, and that he was responsible for his own death by staying on board, according to a February story by seafood publication Undercurrent.