Just staying with combat surface ships since that seems where your question is most focused there are generally three recognized classes of surface combatant in the US Navy and these divisions more or less apply to other major world navies. They are in descending order of size; the cruiser, destroyer and frigate.
The only cruisers left in American service are the Ticonderogo class AEGIS cruisers. They are large multipurpose warships whose primary tasking is air defense with Standard Surface to air missiles of whatever group they are attached to. Some provide air defense for carriers, some provide air defense for amphibous groups or groups of surface ships called surface action groups. They are also capable of engaging submarines with thier SH-60B Seahawk antisubmarine helicopters, ASROC antisubamrine rockets and antisubmarine torpedo tubes. They also carry Tomahawk missiles to attack land targets and Harpoon antiship missiles to destroy other surface ships. A few have been upgraded to perform ballistic missile defense with the Standard SM-2 Block IV surface to air missile. The cruiser is a multirole ship designed to perform all the combat roles required of a surface ship including serving as a command ship for other surface warships.
Then we have the Arleigh Burke class destroyers that are really more like cruisers in capability. They have all the same weapon systems including the AEGIS system of the Ticonderogas but in a more compact package. Originally thier were specialized destroyers like the Spruance class that was optimized to serve as an antisubmarine ship and others that were designed to serve as air defense ships but with the Burkes that distinction has become blurred as they can do both equally well.
Then we have the frigates, in this case the Oliver Hazard Perry class. They were originally designed as escourt ships with a primary antisubmarine tasking using antisubmarine helicopters and torpedo tubes. They had a minimal antisurface and antiaircraft capabiity to allow them to defend themselves but mainly they would rely upon the larger ships to provide air defense. So they can't perform as many jobs as the larger ships, but they are cheaper to build, crew and operate so you can have more of them. They are generally the ones sent on antipiracy or general patrol missions. The USS Stark, for example, was escourting reflagged Kuwaiti tankers in the Persian Gulf in 1987 when it was hit by an Iraqi air-launched Exocet antiship missile.
The majority of our current surface ships were concieved when the single greatest threat against our Navy was massive Soviet cruise missile attacks, designed to destroy our aircraft carriers by saturating thier defenses with dozens to hundreds of missiles at a time. So a system was developed using concentric layers of defense to blunt, disrupt and absorb these attacks. At the farthest out were the airbourne warning and control aircraft from the carrier with fighters flying combat air patrol more than 200 miles out. Thier job was to locate and ideally destroy any enemy bombers before they launched thier missiles.
Then you have the AEGIS ships with thier air defense missiles. The AEGIS system is a radar command and control system that links each of the ships in the battle group or convoy, and can automatically control thier weapons systems to attack incoming targets. At up to 150 miles out the AEGIS would use the Standard missiles on the cruiser to start engaging any missiles that got through the outer layer. Then any missiles that go through that would be engaged by shorter ranged versions of the Standard missile and Sea Sparrow on other surface warships.
Anything that got through that would then be engaged by the individual Phalanx point defense systems on each individual ship or now the RAM point defense missiles we use in addition to them. Each layer was designed to absorb and destroy enemy antiship missile attacks to protect the carrier at the center.
Now that this threat has dissipated the tactic is still on the books but surface ships have became more than cogs in carrier defense. They gained the capability to launch thier own attacks on land targets with the Tomahawk missile and train to operate more independently in wartime.
As for fighting a modern naval battle, if the carrier wasn't around then the surface ships would try to engage the enemy ship with Harpoon antiship missiles and if they didn't destroy the target they would then either attempt to flee or close to engage with thier main guns(5inch guns on the cruisers and destroyers, 3inch on the Frigates) and fight a conventiional gun battle. It all depends upon what they are fighting, a single American cruiser engaging a Russian Kirov class battlecruiser would be suicide for excample. That hasn't happened in a long time. The last large scale naval battle the US Navy fought was in 1988 when Iran sent thier two most modern frigates against the US Navy Persian Gulf force that had just destroyed two oil platforms they had been using to launch attacks on oil tankers. One was sunk by laser-guided bombs from A-6 Intruders and the other badly damaged. The suface ships just provided gunfire support to the special forces who took the oil platforms.
In 1991 the Iraqi Navy was pretty much annihilated from the air and in all other American conflicts since then the naval threat has been minimal.
Edited by tennyson, 05 March 2007 - 12:42 AM.