Old they may be, but the navy's submarines are still stealthy and deadly, Defence Correspondent DAVID BOEY learnt when he visited 171 Squadron, whose motto is 'Invisible, Invincible'
THE Republic of Singapore Navy's (RSN) second-hand submarines, built in the late 1960s, are its oldest boats but their ability to strike unseen from below the waves puts them among its deadliest assets.
The four boats - submarines are traditionally called boats and not ships - have given the RSN cost-effective lessons in submarine warfare since Singapore announced in September 1995 that it would buy these Sea Serpent-class boats from Sweden.
RSS Conqueror and RSS Chieftain, the two already in Singapore, have fired torpedoes successfully in the South China Sea and given the RSN valuable pointers on submarine operations in the area.
Sea trials have proven these old warhorses are quiet and hard to detect. Their heavyweight torpedoes can sink ships at long range.
Their stealthy nature also makes them ideal when covert surveillance at sea is called for.
The two boats now in Singapore will be joined by two more submarines, RSS Challenger and RSS Centurion, when they arrive in Singapore from Sweden.
The RSN unit that operates submarines, 171 Squadron, will adapt and apply lessons learnt in Swedish waters to local waters, said its commanding officer, Colonel Cyril Lee, 43.
'In the Baltic, even in summer the sea water is 18 deg C. We don't need air-conditioning over there because the sea is sufficiently cool to cool the whole boat,' he said.
So Singapore's subs have special air-conditioning plants that are modified to operate quietly, so they're less likely to be detected even by underwater microphones, or hydrophones, in anti-submarine sweeps.
Also, since changes in the temperature of sea water affect how sound waves travel underwater, the submarine's sonar operators must know how to detect ships around them in warmer waters.
Many more ships use the South China Sea than the Baltic, and the ships in the sea lanes around Singapore tend to be much bigger.
This means a sub must operate at greater depths to avoid the bottoms of large ships.
This affects the 'safe depth', the depth at which the sub will be safe from collisions.
Col Lee said: 'The Baltic is a holiday area compared to the South China Sea.
'The traffic density in the South China Sea is four to five times what it is in Baltic sea lanes.'
The Baltic has one specific entrance for ships, and is commonly used by shallow-draught vessels.
There, he said, the deepest-draught vessels the RSN saw were bulk carriers with a draught of 12.7m.
'In the South China Sea, you can encounter 200,000-tonne supertankers which can be 18m to 20m deep when fully laden,' he noted.
The Sjoormen-class submarines - Sjoormen is Swedish for Sea Serpent - built for the Royal Swedish Navy more than three decades ago, may seem past their prime.
However, they will serve as cost-effective platforms for the RSN to learn more about submarine warfare.
Whatever the RSN and its partners from the Defence Science and Technology Agency (DSTA), defence scientists from DSO National Laboratories, shipbuilder Singapore Technologies Marine and the Swedish defence industry have done to upgrade the subs, they aren't giving much away.
Col Lee said: 'The shell is probably the oldest in the navy but when we got the subs, we changed a lot of the equipment inside the submarine.'
And it works.
'For all exercises with surface vessels, we've been able to remain undetected unless it's to facilitate the training of personnel on warships on the surface,' he said.
Locating a sub is like finding a needle in a haystack, he said.
Just 51m long, the RSN's subs are small compared to the nuclear-powered subs of Western navies.
But small is advantageous in regional waters, which are only about 80m deep.
Indeed, this could work against larger subs which will have less room to manoeuvre.
The RSN has drawn up a training programme to ensure it can sustain its ability to recruit and train new submariners.
'The training in Sweden will not last forever and we have to learn how to screen candidates who want to be submariners,' said Lieutenant-Colonel Tan Boon Ann, 34, an operations officer with 171 Squadron.
Anyone in the navy can ask for submarine duty, but they'll be asked why they want to sail underwater on missions that could last about a week.
Lt-Col Tan said: 'If his motivation is the challenges, the exacting training and sense of job fulfilment, we'll have a winner on our hands because you find these people will be more motivated.' However, big egos are not welcome on a submarine, where some two dozen men must live and work in a confined space.
Crew members need to get on well with each other because as one man gets up to start his six-hour shift, another moves in to rest on his still-warm bunk - hence the term 'hot bunking'.
While underwater, the sub maintains the same day-and-night cycle as the time zone in which it operates.
White light is used in the daytime, and red lights come on at night to indicate it's past sunset.
Lieutenant-Colonel Alec Lim, 40, a training officer with the squadron, said submariners are always wary of newcomers, even VIP visitors.
'There's always at least a pair of eyes watching you,' he said, adding that the crew monitor visitors to make sure they don't touch valves or switches without permission.
'Statistically, submarine operations are safe.
'It's only unsafe when you don't know what the hell you're doing,' he said.
The ones who do know what they're doing and have earned the right to wear the dolphin badge on their uniform have come through a few years of training.
Training is done in Sweden and Singapore and with other sub operators such as Australia.
When the RSN holds joint drills with the United States and other navies, it can pick up best practices and apply them here.
Submariners are taught the 'blind man's walk' so they can move about the boat and find what they need if there's a power failure.
'They must have the ability to take humiliation,' said Col Lee.
'For example, even when I was designated commanding officer of the squadron, I had to wash toilets because I need to know every part of the boat.
'Toilets on submarines are different from those on surface ships and this was the way I found out.'
-ST
