Singapore is joining international anti-piracy patrols in the Gulf of Aden for the ninth time since 2009.

On Monday, 151 servicemen from the Singapore Armed Forces left for a three-month stint to protect merchant ships against pirate attacks in the waters off Somalia.

Led by Colonel Cheong Kwok Chien, the servicemen sailed on the Republic of Singapore Navy's stealth frigate RSS Tenacious which was also carrying a Sikorsky S-70B Seahawk naval helicopter.

They will join the multi-national Combined Task Force 151 to patrol the area.

Officiating at the send-off ceremony at Changi Naval Base, navy chief Ng Chee Peng said that by supporting international counter-piracy efforts, Singapore is being "a responsible member of the international community and a maritime nation".

"These piracy attacks disrupt key sea lines of communication and maritime trade, as well as affect the safety of seafarers," added Rear-Admiral (two star) Ng. "This has a direct impact on countries such as Singapore that are dependent on maritime trade."

The latest mission comes on the back of figures from the International Maritime Bureau showing that piracy incidents in the Gulf of Aden dropped to a seven-year low last year. The waterway, which connects the Red Sea with the Arabian Sea and Indian Ocean, saw 15 attacks, down sharply from 75 in 2012 and 237 in 2011.

Members of the public can convey their support to the deployed servicemen on the Sea of Support website: www.seaofsupport.sg