Some sailors have reportedly tried throwing themselves into the sea, basic supplies can run short and sanitation is going awry: life on America's giant Abraham Lincoln aircraft carrier is increasingly difficult as the Iran war drags on.

The ship - now in its ninth month of deployment - is expected to be replaced in the Middle East by another carrier, the George Washington, in a move sure to be welcomed by the Lincoln's crew and their loved ones.

But concerns about conditions on the Lincoln have prompted lawmakers to demand answers from Pentagon chief Pete Hegseth, who insists the situation has been "misrepresented."

Jonathan Schroden, chief research officer at the Center for Naval Analyses, said the warship's sailors face significant challenges from their long time at sea.

"Even in peacetime conditions, the quarters are cramped, the workdays are long, the food is not great, and it's difficult to get fresh air, exercise and even a decent night's sleep," Schroden said.

"Add to that the stress that comes with being involved in combat operations - in which your ship is constantly threatened - and you can see how difficult life becomes for these sailors," he said.

Schroden noted that carrier strike groups are generally designed for six-month deployments for reasons "including sailor welfare."

Going beyond that "creates all kinds of compounding problems that the Navy then has to deal with down the line."

This includes increased maintenance costs and decreased readiness windows while ships are prepared to deploy again, he said.

Of special concern are accounts of suicide attempts aboard the Lincoln, with the Navy Times reporting this week that two sailors tried to jump off the ship.

Schroden said he had seen "reports of similar events occasionally over the past couple of decades" and that "it's rare but not unheard of, though tragic in every case."

The US Navy did not immediately provide answers to questions from AFP, but US Central Command posted on X that the crew "remain resilient and resolved after more than 260 days at sea."

It added that no service members aboard the carrier have died and one sailor who fell overboard on August 3 "was quickly and safely recovered."