As well designed and
maintained as the Republic
of Singapore's combat vessels
are, there are not very many,
and the Malacca Straits are
five hundred miles long.  
Then there's the huge Indian
Ocean area between the
western end and the
Andaman Islands. And the
even larger Pacific Ocean
area between the eastern end
of the straits and the South
China Sea.
Tactically, a
counter-attacker's options
become very limited once
pirates have boarded a target
vessel, especially if the
victim's crew are taken
Even if a frigate or submarine
can get to the scene quickly,
the key is to preempt attacks.
Perhaps pirates intending to remain alive and in business for a
prolonged period would enlist lookouts on shore on in fishing boats to
alert the gentlemen of fortune that a frigate was approaching. This has
been standard practice for pirates for thousands of years. Today, a
pirate king might also invest in radar. However, most radars receive
and send energy, so a warship with advanced systems can "hear"
something it cannot see. So far, even if pirates have radar that leaves
submarines undetected.