Underwater and in pitch darkness, Ms Siti Naqiah Tusliman spends up to four hours scrubbing the underside of a ship. When it is time for her to finally surface, her head, kept dry from the surrounding sea water by the 16kg diving helmet, is beaded with sweat.
Six years ago, Ms Naqiah, then 23 years old and having just earned a recreational diving licence, might have called this a magical experience. But she said: "Now it is completely different. It is very physically and mentally demanding, it's a job that needs a man's strength."
Ms Naqiah, who received her commercial diving certificate on May 26, is the first female diver here certified to use specialised diving gear known as Surface-Supplied Diving Equipment (SSDE) for work purposes in Singapore waters.
She joined an elite club of 63 divers who have attained the highest standard under the local code of practice for diving work, or SS 511.
There are an estimated 200 inshore commercial divers in Singapore, said the Commercial Diving Association of Singapore.
Global shipping companies rely on them to keep their vessels shipshape by scrubbing and polishing the underside of hulls.
Without frequent cleaning, a build-up of waste material can increase underwater drag when ships travel long distances and across oceans.
To a shipping company, this can mean a longer travelling time and more fuel being used, so many are willing to pay top dollar for the divers' services.
Ms Naqiah quit her job as a travel coordinator for shipping crews to chase her dream of an underwater career. While most of her family and friends were supportive of her decision, several voiced their doubts.
"Many people actually told me that this career is definitely not for females. 'It is too rugged, too tough, you cannot do it,' they said."
Even friends who were already experienced commercial divers advised her against it, citing reasons such as the lack of privacy on board ships and the physically-intensive nature of the job. The SSDE gear can weigh up to 50kg on land.
"They said I could not, that is why I tried. I wanted to challenge myself... And here I am," she said.
To prepare for the two-month course, conducted by accredited training provider KBA Training Centre (KBAT), Ms Naqiah hit the gym regularly to build up her stamina and strength.
Said Ms Naqiah: "My first time diving here, when I came up I broke down, because it was very, very different from what I was used to, especially the lack of visibility.
She added: "The most dangerous part of this work is being suddenly hit by something you cannot see. Or suddenly, you hit something. But the thing is not to panic and to remember how we have been trained to react."
So far, Ms Naqiah is the only female to have achieved the highest national standard, said her trainers.
Her path is also unconventional because she had chosen to pay for her own training, unlike other divers, whose companies paid for their training. It was a risky move for her to leave her job, then enrol in training, especially since the industry was a male-dominated one. She was unemployed during the training and was uncertain about whether she could find a diving job.
But the parent company of KBAT, KB Associates, hired her after her graduation.
Ms Naqiah said she was proud to become the first female licensed to use the SSDE here and prove her doubters wrong. During the tough times, she had fought the idea of giving up. "I told myself, if I give up, I will not achieve anything. If I give up, I will later regret, that all this is for nothing."