On Wednesday, his nine-month-old daughter had to be taken to hospital with high fever.

Yesterday, he dived into the murky waters off Lim Chu Kang to search for a missing man.

At around 11am yesterday, Mr Ching, who lives and works on his father's fish farm off the coast of Lim Chu Kang, was feeding milkfish and garoupa on a floating farm less than 100m from shore.

After work, he planned to head to Mount Alvernia hospital to visit his sick daughter.

Hearing shouts in the distance, he noticed a slightly submerged truck near the shore.

Two men were standing on the roof, waving and shouting. They were Mr Chua Kim Swee, 54, the truck driver; and his co-worker, Mr Yong Chee Seng, who was in his 20s.

Mr Ching could not make out what they were saying, but it appeared that they were trying to get help to pull the truck out of the water.

A worker in his 50s from a fish farm closer to the scene, and whom Mr Ching knew only as Mr Sim, noticed that the 24-ft truck appeared to be sinking fast. He rushed to the truck in his motorboat, and he got there just as the roof was about to sink.

A couple of minutes later the vehicle disappeared under the water.

It was then that the two survivors told Mr Sim that their colleague, Mr Goh Chin Went, 21, was still trapped inside the sinking vehicle.

Mr Ching joined Mr Sim and the two survivors.

'They were very panicky. When I heard there was a victim inside I immediately grabbed my goggles and went straight to find the lorry,' he said.

'The thought of a man struggling to get out of the vehicle as water fills it just made me want to try hard to help the man. Even if I could not get to him, at least I could tag the truck so rescuers could get to him quickly.'

With no oxygen tank and hampered by poor visibility in the murky waters, Mr Ching groped around - but in vain.

He surfaced, then dived in again and again, each time at a deeper spot until he could not reach the seabed anymore.

When he surfaced from his third dive, the police had arrived.

Rescuers from the Singapore Civil Defence Force and the Police Coast Guard took over, scouring the area for the missing man. They were later joined by naval divers.

The two survivors, Mr Chua and Mr Yong, were unhurt but were still in shock an hour after the incident.

Mr Chua was seen burying his face in his hands while rescuers searched for Mr Goh.

He told The Straits Times that they had been taking delivery of live fish from the fish farms, which is done up to thrice a week.

Everything was as usual, and he had pulled the handbrake and wedged rocks behind the wheels before the three men entered the back of the truck.

As they were loading the vehicle with drums of fish, he suddenly felt the truck shake and then begin rolling backwards into the water.

As the two survivors tried desperately to escape from the compartment, using the rising ramp to help them clamber onto the roof, they caught a glimpse of Mr Goh - known to his co-workers as Ah Boon - holding on to the drums of fish.

They were puzzled as to why he was doing so, when the ramp was already rising.

'We were just frantic. All we could think of was getting out. We yelled at Ah Boon to follow us,' Mr Chua said.

Those who frequent the area say the coastline is slippery especially when wet, because of the algae build-up.

Hearing about the accident, about a dozen of Mr Goh's colleagues at Sheng Siong Supermarket - including a few directors - rushed down to the scene.

Mr Goh Eng Lai, 53, an assistant executive with Sheng Siong who is in charge of the live fish section, said Mr Goh Chin Went came from Johor in Malaysia to work here.

A hardworking man with a positive outlook, he had been with the supermarket for the last three years.

He was single and lived with his father, who also works in Singapore, in a rented Marsiling flat.

Meanwhile, Mr Ching, whose desperate attempts to save the trapped worker proved fruitless, left for Mount Alvernia Hospital to visit his daughter. She still has a fever but is holding her own.

tracysua@sph.com.sg

joolin@sph.com.sg

carolynq@sph.com.sg