It is always prudent to consult history, particularly here. Small warships are as old as naval combat itself, but until recently, small vessels were unable to challenge larger ships because they lacked sufficient stability and freeboard to sail in the ocean, as well as sufficient firepower to even dent the armor of larger vessels, they posed no threat to large surface combatants. This changed in 1866 by the invention of the torpedo, which allowed small boats to successfully defeat much larger battleships. The subsequent introduction of the torpedo boat in 1877 created a panic in naval circles since it was believed that swarms of torpedo boats would allow tiny nations to lay waste to huge, expensive fleets, forever upsetting the balance of power. However, as Mahan observed, these boats were akin to fire-ships in that they were effective at striking fear into the enemy but not very effective at sinking ships. Torpedo boats suffered from the same fates as earlier small craft, plus some new ones: they were dangerous in open waters, had short ranges, could only engage enemy ships effectively at short ranges (at which point they would be ripped up by low-caliber guns), and were too small to carry advanced aiming devices or range finders, a fault that doomed them to inaccuracy. Indeed, early torpedo boats were almost total failures: torpedoes boats in the Russo-Japanese war only sunk one ship that had already been rendered crippled and immobile by battleship fire, and improved torpedo boats in WWI still only sunk one cruiser in the entire war. The destroyer, originally built to defend fleets against the torpedo boat, had largely replaced the torpedo boat by WWI since destroyers were more seaworthy, had a longer range, carried better detection equipment and, most importantly, had guns and depth charges to provide adequate defenses against submarines, aircraft, and surface ships. This trend continued through WWII, where torpedo boats were hampered by increased fleet speeds (which denied torpedo boats the speed and agility advantage they had long relied on) and long-range patrol aircraft, which could detect and defeat torpedo boats before they even came close to an enemy fleet.
Postwar, small vessels again underwent a renaissance. The invention of the guided missile, coupling with the shrinking of electronics, particularly radar, gave rise to the missile boat, a type of fast, short range boat designed to sink larger ships with swarm tactics and then escape speedily. Some larger missile boats could even carry close in weapons systems (CIWS) to defend against enemy missiles and SAMs to protect against aircraft, which ought to have taken away the main liability of torpedo boats: their extreme vulnerability. Initially, it looked as if missile boats were the huge threats that torpedo boats were supposed to be. This is illustrated by several events, especially the famous sinking of the Israeli frigate Eilat by an Egyptian Osa-class missile boat in 1967; the destruction of four Pakistani ships, including a destroyer and two large merchantmen, by Indian missile boats in 1971; and the sinking of five Syrian missile boats by six Israeli missile boats at the Battle of Latakia (the first battle between two fleets of missile boats) in 1973. However, it must be borne in mind that in all three of these engagements, the losers were primarily obsolete ships that lacked defensive countermeasures. The effectiveness of countermeasures, particularly CIWS guns and missiles, has been well demonstrated: the successful use of electronic countermeasures and chaff by the Israelis at Latakia and the effective use of CIWS missiles to defeat anti-ship missiles by the Royal Navy in the Falklands War provide two good examples. Finally, missile boats are still extraordinarily vulnerable to attacks from aircraft and surface ships. To wit, NATO helicopters made short work of the Iraqi Navy's missile craft in the Gulf War, and the U.S. Navy destroyed three Iranian speedboats and one Iranian gunship with aircraft and ship launched missiles in Operation Praying Mantis while taking no casualties.
So the threat posed by Iranian speedboats may not be so dire after all. However, the fact that Iranian speedboats could potentially pose a threat means that the U.S. Navy must create a means by which to defeat this threat. A strategy for defeating Iranian missile boats must be both offensive and defensive: that is, the Navy must be able to both sink Iranian boats and defend itself against attacks by them.
The offensive aspect of fighting Iranian boats is mostly already taken care of. Combat air patrol can be expected to detect incoming Iranian craft and fire on them. However, because Iranian missile boats are small and fairly stealthy, they may be difficult to detect from high altitudes. Thus, it would be prudent to devote a small portion of a carrier's combat air patrol to low-altitude searches for Iranian boats. As the success of helicopter operations against Iraqi missile boats in the Gulf War demonstrates, helicopters can provide a valuable defense against missile boats. However, a helicopter is useless if it is not armed, so the Navy must have its anti-submarine and patrol helicopters carry some kind of light anti-ship missile such as the AGM-65 Maverick (I choose the Maverick because it is currently in U.S. Navy inventory and since its effectiveness against small craft was already demonstrated in the Gulf War) while in the Persian Gulf. Further, surface ships can effectively defeat missile boats using their light guns and anti-aircraft missiles. However, surface ships are useless if they do not detect Iranian craft, so it must be ensured that all Navy ships are equipped with the very latest sensors, and that these sensors are always on.
The main area of concern regarding Iranian missile boats is defense. U.S. Navy vessels are equipped with highly advanced CIWS and electronic countermeasures, which ought to provide adequate defenses against Iranian boats. All Navy ships ought to be equipped with these CIWS guns and electronic countermeasures (ECM). Some ships that currently carry CIWS and ECM ought to carry more of it, particularly the Arleigh Burke flight IIa destroyers (which only carry 1 Phalanx CIWS gun, and ought to carry 2 to give them protection fore and aft) and the Nimitz, Enterprise and Gerald R. Ford class carriers, which all could benefit from more CIWS guns and missiles located in more locations on the ships, to give the carriers 360 degree defensive coverage and redundancy in defenses so that if one CIWS system fails, another can take its place. Also, the U.S. Navy needs to avoid the fate of the INS Hanit (an Israeli corvette hit by a missile because she forgot to activate her countermeasures) and keep ECM and CIWS ready to use at all times, in addition to keeping sensors running at all times to ensure long-range detection of enemy combatants. Finally, to prevent "swarm" attacks, in which vast numbers of small boats overwhelm larger ships by forcing the latter to expend all of their defensive weapons on endless waves of boats, the Navy needs to upgrade all ships to carry AESA radar, which can track more targets than current radars can. Further, U.S. warships ought to carry more ammunition for all of their weapons in order to not get overwhelmed by large numbers of enemies.
Thus, the supposedly lethal threat of Iranian speedboats may not be so scary after all. History has shown that small craft never live up to expectations. The Navy currently has the means to defend itself against any number of small craft attacks, and it can be expected to do so in the event of a conflict. It is probably now time for the naval brass to start looking for the next unbeatable threat to naval supremacy.
