The navy's combat divers, like the commandos, are among the Singapore Armed Forces' toughest servicemen. Only the fittest are picked for a chance at this elite military vocation, and not everyone survives the rigorous training regime that pushes their physical and mental endurance to the limit. Photojournalists ALPHONSUS CHERN and CAROLINE CHIA tracked a batch of trainees through their five-month journey to become combat divers, watched as many dropped out along the way and had a ringside view of the toughest five days of every trainee's life, Hell Week.
TENSION hangs over a four-storey block in Sembawang Camp in the wee hours of a Monday morning, as 74 trainees of the 40th Combat Diver Course toss fitfully in their cabin beds.
At precisely 2.30am, Second Warrant Officer (2WO) S. Rajendren strikes a handheld grenade simulator known as a thunderflash and waves it into a shallow drain.
The blinding explosion galvanises other trainers, already in position. They pound on the wooden bunk doors, screaming unabatedly while tossing unguarded rucksacks and loose footwear down the corridors, sending befuddled trainees scrambling after them.
Drugged with sleep and sagging under the weight of their olive-green packs, the young men crawl down the stairs on all fours, spilling onto the concrete parade square like a colony of evicted egg-carrying ants, to a drenching welcome with fire hoses.
On cue, several trip flares burst into life, illuminating the chaos in a bright orange glow, casting grotesque caricatures of the disoriented men onto the walls of the building - a shadow play gone awry.
From a corner, a machine gun punctuates the cacophony with a shattering staccato that reverberates in the cool night air.
Standing on a platform above the maelstrom of swirling smoke and glistening rain in his dark blue instructor's T-shirt and camouflage slacks, 2WO Rajendren is the man in charge of this mayhem.
Feared and respected in equal measure by the trainees, the training officer's drills are their first taste of the long night ahead. "On your belly, on your feet, on your backs! Push-ups, crunches, jumping jacks in position, ready!"
The bewildered trainees are out of sync, unable to keep up with the impossibly quick commands belted through the megaphone slung from his shoulder.
Hawk-eyed instructors prowl the ranks, blasting banshee-like whistles and stabbing torch beams into the sodden jumble of limbs.
Twenty minutes into the commotion, every trainee is soaked and utterly miserable.
Although every one of them knows this moment must arrive, nothing can prepare them for the actual bedlam of "Breakout" - the opening act of the combat divers' Team Building Week.
Held during the seventh week of the course, this naval diver's rite of passage is better known as Hell Week.
Five months earlier, 450 young men began this journey when they received posting orders to the Naval Underwater Medical Centre for a vocational assessment.
A battery of tests would ensure that only the finest physical specimens were selected.
Within pristine confines, orderlies measured each man's body fat and lung capacity, probed the integrity of his ear drums, wired him to an electrocardiograph to monitor his heartbeat, and then packed him into a pressure chamber sealed with double hatches to see if he could bear a simulated dive to a depth of 10m.
Still intact, each candidate then had to change into physical training attire to attempt his best scores in the standing broad jump and chin-up stations, strip to his trunks for a 25m swim, then present himself for a face-to-face interview with a senior instructor, usually a warrant officer with years of diving experience.
Here, any fears of the deep a candidate might have were put to rest, while his character and motivation were probed with questions such as: "Are you afraid of water?", "What school co-curricular activities did you take part in?" and "Do you want to be a naval diver?"
The final stop of the day was a psychological assessment. The multiple-choice test involved a multitude of questions to determine if he would be able to cope with the stresses divers experience frequently on the job.
Those who cleared the selection moved on to nine weeks of Basic Military Training (BMT) modified to include pool training and an introduction to maritime culture with terms such as "port" and "starboard" replacing "left" and "right".
Now, the numbers were whittled down again, as those who failed the water confidence and physical fitness standards were posted to other units.
Of the 450 initially called up, less than a quarter entered the five-month Combat Diver Course to learn military scuba diving and push their bodies to unprecedented levels of physical endurance.
Private Nigel Tan, a member of the Ngee Ann Polytechnic Scuba Diving Club before national service, felt both privileged and nervous when he received his posting letter.