Without a doubt, the biggest surprise (so far) of the current Middle East conflict was Friday's partially successful missile attack against an Israeli Navy corvette. We saw "partial" because the Israeli vessel (the Ahi-Hanit) survived the attack, despite moderate damage, and the loss of four crew members. Early speculation suggested that the missile might have suffered a partial malfunction, or that the Israeli vessel might have been partially shielded by an Egyptian merchant ship, which was also struck by a missile at about the same time. However, later analysis revealed that the two vessels were miles apart at the time of the attack, and both ships were clearly targeted by Hizballah gunners and their Iranian "instructors."
The fact that the corvette managed to limp back to port is a credit to Israeli ship-handling and damage control skills. The missile used in the attack, an Iranian-built C802, carries a large warhead and is more than capable of sinking even larger vessels. Available reports indicate that the Ahi-Hanit was targeted by at least two C802s; the first apparently missed; the second struck the corvette near its aft helipad, igniting a large fire that was later brought under control. Israeli military commanders believe that the missile may have actually been fired by an Iranian crew; Tehran has a sizeable inventory of Silkworm-series anti-ship missiles, and a number of personnel who are proficient in their use. Additionally, Iran's intelligence service (the MOIS) and Revolutionary Guard Corps (IRGC) maintain a continuous presence in Lebanon, providing a mechanism for smuggling missiles and crews into the country.
What's surprising about the attack is that Hizballah and/or Iran managed to pull off the strike, despite a heavy Israeli ISR (intelligence, surveillance and reconnaissance) presence. In support of air strikes in Lebanon, the Israelis are using significant numbers of UAVs and intelligence collection aircraft. Yet, these assets failed to detect preparations for the attack, including establishment of firing positions, and (possibly) radar emissions that may have preceded the strike. In most cases, the C802 utilizes a sea surveillance radar for target acquisition, helping the crew sort through local sea traffic. The surveillance radar gives the crew an initial "line of bearing" for launch; once fired, the missile has its own on-board radar to lock onto the target, and guide it to the ship.
If an acquisition radar was used, Israeli ELINT collectors should have detected it, and provided some sort of threat warning to vessels in the area. If an acquisition radar was not used, there's still the question of how Israeli surveillance drones missed the movement of the missile to coastal areas, launcher set-up, and other preparations. While a skilled crew can complete these tasks in only a few minutes, the Israelis pride themselves on their employment of UAVs and ability to maintain persistent surveillance over the battlefield. Obviously, the Israeli ISR system failed on Friday, and there will almost certainly be an inquirty to find out what went wrong. There are a number of potential explanations; in some cases, information developed in ISR channels doesn't always flow to the operators in a timely manner. Additionally, there's the very real possibility that the launcher was effectively concealed prior to the operation, and may have been camouflaged until just before the launch. If that was the case, it would suggest that Hizballah (and the IRGC) are much more adept at camouflage that previously believed.
Friday's missile attacks have clear implications for the U.S. With a non-combatant evacuation operation (NEO) getting underway in Lebanon, U.S. vessels will have to move closer to the Lebanese coast, possibly within range of the C802. American naval vessels are well-equipped to defend themselves against a missile attack, but with the large numbers of U.S. citizens and dependents scheduled for evacuation (25-70,000, by some estimates), commercial vessels--such as cruise ships--may be used. Saying that cruise ships would present an inviting target is an understatement, to say the least. On the other hand, keeping those huge ships out of missile range would mean longer flights for helicopters, and a longer evacuation process.