"New technology, changed strategic circumstances, budget pressures and industry rationalisation are all playing a part in redefining the size and shape of the market for non-nuclear submarines. Conventional submarines continue to enjoy popularity with many navies because of the disproportionate impact that they can have on military operations in the maritime domain, both above and below the waterline. Fitted with improved quieting sensors, weapons and propulsion systems readily available in today's market, submarines can operate undetected near a regional adversary's coast, covertly conduct surveillance, engage enemy naval forces, and expand their nation's regional impact still further. Covertness brings another attribute. Operating unseen and unannounced, the submarine can be forward deployed without undue provocation, thereby avoiding crisis escalation or political embarrassment. For many smaller nations the conventional submarine is still regarded as an attractive and cost-effective means of sea denial against far more powerful potential adversaries."