US Navy veteran Jonny Burnell spent 111 days aboard the warship USS Vinson during the US war with Afghanistan in 2001.
His role as a Navy photographer allowed him to visit crew throughout the ship, unlike most sailors who are confined to parts of the vessel where they work. In an age before digital photography, troops were often eager to get their picture snapped whenever they saw him.
Over more than three months aboard the USS Carl Vinson, he witnessed a change among the crew as their excitement and energy faded to what he called a "sadness".
"There was one point where there was a visible kind of deadness in the shipmates' eyes", he recalls. "I still think the hardest part of my job was watching the sadness in people's faces every frickin' day."
Burnell told the BBC he's been watching on the brink of tears as concern mounts about conditions aboard the USS Abraham Lincoln - which has been deployed as part of the US-Iran war since 11 December, more than double his deployment aboard the Vinson.
Military on the Lincoln are reportedly contending with food shortages, broken plumbing and exhaustion, according to two US publications that cover the military - the Military Times and Stars & Stripes.
Family members of sailors onboard have expressed concern about their mental health deteriorating due to the conditions, with some sailors having reportedly attempted to jump overboard.
Military officials have disputed that there are severe issues afflicting the ship, and some veterans have also suggested that the accounts in the media are overblown.
The reports in the media are largely inaccurate, and "99% hype," says retired Navy Lt Commander Steve Rogers, Director of the Association of the United States Navy (AUSN).
As part of his job for the AUSN - a non-profit that works to help US Navy servicemembers - he has been speaking to relatives of troops on the Lincoln. He says its normal for families to worry about their loved ones at war, and that the troops are well prepared for the situation they find themselves in.
In an interview with the BBC, a relative of one sailor on the Lincoln said that their family member had lost 65lbs (29kg), and has been suffering from exhaustion because of the constant noise and vibrations.
Asked about the situation aboard the Lincoln on Friday, Trump dismissed the reports, saying the deployment is "not nearly long enough". On Sunday, the head of US Central Command, which oversees operations in the Middle East, released a statement saying that of the 11 active aircraft carriers in the US military "the Lincoln currently has among the lowest number of cases related to mental health".
"This doesn't mean all is perfect," said Admiral Brad Cooper, adding that "service at sea for long periods isn't for everyone".
"It is uniquely challenging and tough," he continued, adding that "mental health is another aspect of individual health and requires our attention just like physical health and spiritual health".
It remains unclear what the conditions on the Lincoln are like now. A crew from CNN visited last month, and did not discover any widespread issues during the three days on board. Several troops mentioned being forced to ration food, and losing weight over "many months", but when CNN boarded on 7 July, "food was plentiful," the outlet reported. Showers were also hot, although there were some signs of mould.
The US has deployed another battleship to relieve the Lincoln, which should arrive in the Middle East in another week.
The replacement ship, the USS George Washington, has had its own history of mental health challenges.
In 2022, a spate of suicides aboard the ship - while it was still docked at a port in Virginia - led to a military inspector's investigation. The conclusion of the investigation found the deaths were not caused by any one issue, but were the result of several problems related to poor living conditions.
The report, released in May 2023, found that the Navy's top brass had "let our standards slip - and in doing so we let our people down."
Dr Harold Kudler, the former head of mental health policy for the US Veterans Administration (VA) says the issue has been studied by the US government for years.
Kudler says the isolation of being aboard a ship, with moments of prolonged boredom followed by "extreme alertness", can amplify mental-health struggles.
"You don't know where the front is," he says, describing the situation aboard the Lincoln.
"Especially in this kind of asynchronistic war that we're seeing."
These factors can be overwhelming, for both enlisted troops and officers as well.
"You're isolated. You don't know exactly what's going to happen. You're not even sure what the mission is anymore. And you don't know when you're going to come home."
During World War 2, the military created a training film to help soldiers who may be dealing with "combat irritability".
The film depicted a sailor who was below deck, tasked with watching machines in an enclosed, lonely room while the war against the enemy raged outside.
"He can't see the enemy. He doesn't know what's going on topside. His job is to watch the two gauges in the engine room," Kudler says.
The point of the film was to illustrate that troops who don't directly fire weapons are still "under tremendous stress, high alertness and subject to exhaustion".
Part of Kudler's time with the Veteran Administration included studying suicide. Years of research by the VA has determined troops and veterans are at a 50% higher risk of suicide compared to the general American population.
The challenge for the military is to make each soldier and sailor feel like an important part of the overall mission, while also acknowledging some of the monotony of being a cog in a larger machine, he says. To combat the isolation and boredom, troops sometimes do fun activities aboard the ship, like hold singing competitions and picnics on the top deck.
Kudler supports the call by Democrats in Congress to lead an investigation into the situation onboard the Lincoln, and how it got to this point.
"The ship can only perform as well as its crew," he says.
"Those 5,000 people comprise a community. Not just men and women under stress. It's a community under stress."
"The capabilities of the ship fall off as the crew falls off. So if the reports that are being shared are true, one really has to worry."
Rogers, of the AUSN, has spent weeks at a time on small Navy ships, and says that issues with depression and boredom are normal among military ranks.
"We're all human beings. We all go through difficult times."
He blames the media for spreading false information, which he calls "absolutely outrageous", and is enraged by the harm he says it is causing to the morale of troops and their families.
Troops can be bored or anxious, but the ships they are on have chaplains and mental health counsellors, he says, and the troops are well-equipped to deal with the stress.
Reported talk of sailors debating whether to jump off the ship is overblown, he contends, recalling jokes that were made during his time on an aircraft carrier.
"I remember one guy said, 'I wish I could parachute outta here,'" he chuckles, dismissing it as "locker room talk".
