As a child growing up on Queensland’s Sunshine Coast, Sub Lieutenant Toia Mangakahia had a passion for travel and learning.

Joining Navy through the New Entry Officers' Course as a maritime warfare officer (MWO) submariner, Sub Lieutenant Mangakahia said she wasn’t completely sure what she was going for, but knew it was a job that would help her grow and develop her own capabilities. 

“The MWO course is two years of incredible dedication. You have to memorise every word of the [Sea] Rules of the Road – all 41 of them – and their annexes,” Sub Lieutenant Mangakahia said. 

“There is so much to learn: navigation, damage-control protocols, and safety measures, to name but a few.

“For me, the most challenging part has been remembering to keep things in perspective and remain positive in times of adversity.”

Sub Lieutenant Mangakahia was one of 31 graduating officers awarded their Bridge Warfare Certificate at HMAS Watson on December 10, gaining her professional qualification as a MWO. 

The role of MWO offers opportunities in science, technology engineering and mathematics (STEM) and requires a particular aptitude for maths.

In school, Sub Lieutenant Mangakahia enjoyed the creative arts and music – she plays piano, guitar, bass and sings – but also enjoyed advanced mathematics.

“Basic math equations are used every day as an officer of the watch,” Sub Lieutenant Mangakahia said.
‘You have to calculate speed, time and distance to determine your speed of advance to a rendezvous position, or how long it will take to travel a certain distance.

“We use mathematics during evolutions to ensure accuracy – for example, during a replenishment at sea when two ships are underway, you have to know your mathematical calculations are accurate.

“As you are approaching the other vessel, you need to be close enough to execute the objective while keeping your crew and the ship safe in addition to all the environmental factors, so there is a lot to work through.”

Along with her MWO course classmates, Sub Lieutenant Mangakahia had a moment to celebrate with friends, family and instructors at the graduation ceremony at HMAS Watson and reflect on her achievements. 

“Over this course, I have served in six platforms, spent 324 hours in the bridge simulator – 84 of those as officer of the watch – and I know I still have so much to learn,” Sub Lieutenant Mangakahia said. 

“I would say to anyone looking for a career in Navy who really wants to be challenged and pushed to their limits, then MWO is for you.

“I am very excited to start my next adventure and head into the fleet.”

To find out more about a career in Defence, visit