Freelance photographer Chen Chuanren, 29, grew up hearing stories of the sea from his father, who sailed for about 27 years. He was also a regular attendee at the navy's open house, and has lived in Marine Parade since he was two, where he could see the sea from his HDB flat.

Mr Chen's association with the navy and the sea developed his fascination for all things nautical and fuelled his interest to do a photo book to mark the Republic navy's 50th anniversary this year. Also, when he learnt that the RSS Sovereignty would be decommissioned soon, he requested to mark the occasion by photographing its last crew.

"Most Singaporeans are unaware of how much goes into protecting Singapore and I wanted to give them a behind-the-scenes look at what goes on," he said yesterday at the launch of his book, By Day & By Night: Missions Of RSS Sovereignty.

The 100-page book contains some 200 photos he took of the patrol vessel and the crew over six to eight months, including seven days spent on board.

RSS Sovereignty crew members and Mr Daniel Chui, chief executive officer of Oceanic Group - the main sponsor of the book project - were at the book launch yesterday.

A photo exhibition, showcasing 20 frame prints from the book, is being held at the DECK, an independent art space, in Prinsep Street till May 20. Visitors can place bids, with all proceeds going to the President's Challenge charity.

The book can also be purchased at the exhibition, but limited copies are available. The book is expected to go on sale in bookshops soon, and will sell for $29.90. For every purchase, $1 will go to the President's Challenge charity.