A fast moving boat cuts steadily across the Singapore Strait, one of the world's busiest shipping lanes. Unknown to the four men onboard, a sleek grey hull vessel along the strait had turned around towards them. 

In an instant, the grey vessel lit up its strobe light and siren and sped steadily towards the fast moving boat, deemed to be suspicious.

The grey vessel skillfully manoeuvred through other maritime traffic in the vicinity, and the pursuit ended in seconds when the boat stopped in the water.

Such a pursuit in open waters would usually have required manned vessels to intercept and investigate the contact of interest.

But this time, sailors were not at risk as the grey vessel is the Singapore navy's new maritime security (MARSEC) unmanned surface vessel (USV). 

The intercept-and-investigate scenario on Tuesday afternoon (Feb 4) was the first time the navy was demonstrating the use of its USVs for maritime security operations - an option which allows the navy to reduce the risks faced by its sailors and maintain persistent effect over its area of operations. 

This vessel began patrolling Singapore waters in 2025, with three of them already in service conducting maritime security missions alongside the Republic of Singapore Navy's other ships.

A fourth will join the fleet later in the year. 

The MARSEC USV measures 16.9m long and weighs 30 tonnes. Powered by two diesel engines, it can attain speeds in excess of 25 knots (46kmh), and can stay out at sea for as long as 36 hours.

Designed and developed locally

The Singapore navy first ventured into unmanned operations in 2004, starting with commercially available solutions.

Its first USV was not equipped with autonomy that enables safe navigation through Singapore's crowded maritime environment. 

AsiaOne understands that first-generation operators, who also had a restricted view of the real-world maritime traffic situation, faced challenges when remotely piloting the USV.

This sparked the indigenous effort between the navy, Defence Science and Technology Agency (DSTA), and the DSO National Laboratories to build an autonomous collision detection and collision avoidance (CDCA) algorithm, tailored for Singapore's unique and cluttered maritime environment. 

The CDCA algorithm utilises the USV's navigation and collision avoidance equipment such as 360-degree cameras, GPS and radar to automate collision avoidance decision making - based on international regulations - similar to the "driving rules" on the road.

The result? A locally designed and developed USV which can assess and respond to maritime traffic situations in a predictable manner, similar to that of a manned vessel. 

With Singapore's aging population and declining birth rates, the USV also provides resource efficiency. 

It can be operated by just a two-man crew from a shore-based control station, and will eventually be mainly made up of full-time (NSF) and operationally ready national servicemen (NSmen).

The MARSEC USV, having now entered operational service, will provide the Singapore maritime security system with another layer of surveillance and operational response.

For starters, its endurance time of more than 36 hours will provide more persistent coverage in the Singapore Strait.

It also allows manned warships such as the littoral mission vessel to be deployed for more complex missions. 

That's not all.

The navy said that it will continue progressive experimentation to enhance these USVs for a wider range of maritime security operations. 

editor@asiaone.com

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