AT 3AM, when most people are fast asleep, Ms Mabel Hu's work-day may just be starting.
A senior harbour pilot, she works nine-hour shifts that begin at varying times. Her job is to help ships, some as long as 400m, to sail safely into Singapore's port waters.
The 39-year-old said: "No two jobs are the same. You don't get to go on the same ships every day... We have only a short time to assess the situation and the people we'll be working with."
She started out at the age of 18 as a deck cadet and 21 years on, she has no regrets. "I grew up at sea," she said.
In 2004, she became the first female harbour pilot in Singapore.
She faced stereotyping and jokes from others at first. Even so, she said: "It doesn't matter if you are male or female - if you want to do something and keep focused on it, you can achieve it. I followed my heart and would encourage others to do so too."
She is among the dozen people featured in the National Geographic's documentary, Inside Maritime Singapore, that is set to air today at 7pm across Singapore, Hong Kong and the rest of South-east Asia.
It will be shown on the National Geographic Channel, with repeat telecasts at 9pm today and at 1.25pm this Friday.
The documentary follows how Singapore's port has grown from a colonial trading outpost. It will also focus on the lives of people in the maritime industry, and how they ensure that its various sectors function smoothly.
"I hope it will encourage more people to join the maritime industry," said Ms Hu.