The Ministry of Defence made a sensible and practical decision to add two more submarines to Singapore's naval assets (Singapore to buy two new submarines; May 17).

Submarines are lethal underwater military hardware, sought after by many countries to protect their sovereignty.

But because of their high price tag, not many countries can afford them.

Their effectiveness was clearly seen in World War II, where submarines, especially those built by Germany, were much feared by the allied forces.

Stealth capabilities add to their potency underwater.

Together with other naval assets, submarines are a powerful deterrence to any attacks from the sea.

Roy Goh Hin Soon