A drone flies low over a snow-covered shipyard in Russia's Far East, where workers toil in subzero temperatures to maintain the hulking vessels during the bitter Siberian winter.

The process of 'vymorozka,' which roughly translates as 'freezing out,' is backbreaking and tedious work that takes weeks in some of the world's harshest conditions, with temperatures dropping to minus 50 degrees Celsius (-58 F).

Workers chip away at the ice encasing the ships, looking for areas in need of repair. The vessels are docked in the harbour of Yakutsk on the banks of the Lena River, Siberia's economic lifeblood in summer, during the winter months.

Locals in Yakutia, Russia's largest republic by landmass, name 'vymorozka' as one of the hardest jobs in the world, but the workers themselves say it's all a matter of perspective.

"You dress the right way and that's it. When you come (to a heated building) and get undressed, it's like a sauna, steam rises from you," worker Mikhail Klus, 48, told Reuters as he took a break from cutting through the ice with a chainsaw.

"I don't think it's the hardest job - there are jobs even harder than that, but it's probably one of the hardest jobs...One needs to try to understand, needs to love the cold and working in it."

The work requires not only stamina and strength, but also extreme precision.

The labourers must be sure not to cut the ice too quickly and break through to the water below. If they do, the carved dugout can be submerged and the work is lost.

The colder the weather, the better the ice freezes and the smoother the job, although the temperatures are hard on some workers.

"Sometimes, when you freeze, you feel negative emotions from it," 22-year-old Artyom Kovalec said from under a thick layer of coats, a pickaxe in his mittened hands.

"You feel it's too cold to work, you want to go home, to eat and relax, so you have to get a grip on yourself."

(Reporting by Reuters; Writing by Lucy Papachristou; Editing by Ros Russell)