More video on the links below
I have long felt there is a gap in the Coast Guard’s ability to respond to a maritime terrorist attack, in that the Coast Guard is unlikely to be able to stop such an attack if it employs a medium or large merchant ship manned by a determined crew. The large cutters are not likely to be underway in the vicinity when need, and the smaller cutters are not adequately armed.
The threat requires at least an ability to forcibly stop a ship, regardless of size, before it gets to its target.
Historically the objective was more frequently to sink rather than stop merchant ships. Turns out merchant ships are very had to sink unless torpedoes are used. There have not been many examples of attempts to simply disable a vessel, but the US blockade of Iran has given us several recent examples.
U.S. forces disabled an oil tanker in the Gulf of Oman at 11:20 p.m. ET on June 10after the vessel violated the blockade against Iran by attempting to transport Iranian oil, marking the third commercial ship disabled by American forces this week.
U.S. Central Command (CENTCOM) acted against Guinea-Bissau flagged M/T Jalveer as it attempted to transport oil from Iran through the Gulf of Oman. A U.S. aircraft fired two Hellfire missiles into the ship’s engine room after the crew repeatedly failed to comply with directions from U.S. forces.
Earlier this week, U.S. aircraft disabled Palau-flagged vessels M/T Marivex and M/T Settebello on Monday and Tuesday, respectively. Marivex violated the blockade by attempting to sail to an Iranian port and Settebello attempted to transport Iranian oil.
CENTCOM forces have disabled nine non-compliant vessels,
At 11:14 p.m. on June 9, U.S. forces disabled an oil tanker in the Gulf of Oman for the second consecutive day after another vessel violated the ongoing blockade by attempting to transport oil from Iran.
U.S. Central Command (CENTCOM) disabled Palau-flagged M/T Settebello as it transited the Gulf of Oman. A U.S. aircraft fired precision munitions into the ship’s engine room after the crew repeatedly failed to comply with directions from American forces.
U.S. Central Command (CENTCOM) enforced blockade measures against Botswana-flagged M/T Lexie as it transited international waters toward Kharg Island. The ship’s crew ignored repeated warnings, failing to comply with directions from U.S. forces multiple times over a 24-hour period.
A U.S. aircraft ultimately disabled the vessel by firing a Hellfire missile into the ship’s engine room, preventing the tanker from reaching Iran.
U.S. forces operating in the Gulf of Oman enforced blockade measures by disabling a Gambia-flagged maritime vessel attempting to sail toward an Iranian port, May 29.
U.S. Central Command (CENTCOM) forces observed M/V Lian Star transiting international waters toward an Iranian port on the Gulf of Oman and issued more than 20 warnings while informing the vessel it was in violation of the U.S. blockade.
A U.S. aircraft disabled the vessel by firing a Hellfire missile into the ship’s engine room after Lian Star’s crew failed to comply.
It certainly appears Hellfire has become the go-to munition for disabling these ships. It is less clear how disabled they really were. Could they have continued their voyage? Were they really unable to continue or were their civilian crews really simply intimidated. I haven’t heard anything about tugs taking them in tow.
It is an important question of the Coast Guard because if they were really successful in fully disabling the ships, this could be the system we need. It could not only take on large ships, it would also be very effective against small, fast, highly maneuverable threats.
Chuck Hill's CG Blog 
Very expensive missile system. I’d be just as interested in knowing if USN/DARPA have refined AiS and GPS spoofing/jamming techniques to exploit and gain control of ships systems and render them more vulnerable to directional exploitation. There was much successful live testing with this at least twelve years ago when I studied it and by now I would hope we’ve mastered it.
The story: https://maritimeoptima.com/insights/signal-wars-at-sea-ais-and-gps-jamming-and-spoofing-explained
The Hellfire’s successor, JAGM, also has some anti-USV capability.
It can be launched vertically from launchers not requiring much if any, deck penetration.
It maybe not be the perfect weapon for all maritime scenarios but it is credible in many.
JAGM looks like a Hellfire. Essentially it is an improved hellfire with greater range and the option of fire and forget, but if you want to hit a specific area of the ship, the semi-active laser homing native to the base versions of Hellfire and optional on JASM may still be the best option.
I thought there was a ship stopped with Mk45 5″ practice rounds that just penetrated all the way through the compartment and destroyed anything in its path.
a 5″ will work, but we currently have none and it is a lot harder to add than Hellfire. Impossible to add to the Webber class WPCs that I see as the primary asset for countering marine terrorism.
1st) “…but we currently have none and it is a lot harder to add than Hellfire.” USCG assets ? . . sure. However, there are a lot of DDG-51s in the Straits right now and that is what I was referring to.
2) The Mk110 57mm does not have ‘no warhead’ training rounds?
3) I am with you on FRC upgrades, and always thought the minimum armament should be Mk38 Mod4 in at least 30mm with dual feed. That WILL stop the function of an engine room once penetrating the hull with armor piercing. As (or should) the FRCs as a class get the RPS-42 radar upgrade for anti-drone work, then that Mk38 Mod4 mount may need dual feed (pun intended). We should have licensed manufacture of Mk38 mounts RIGHT NOW IMHO.
At least theoretically the 25 mm guns on the FRCs could be replaced with 30mm guns with little change to the mount itself. I have been told that was done with the FRCs in PATFORSWA but I have seen no confirmation. That would give us both a more powerful anti-surface weapon and, with the air burst projectile, a new counter UAV capability.
Hellfire/JAGM/Spike-class missiles work, whether with armor-penetrating warheads or inert warheads which I’m hearing may also have been used. FRCs an others should have either a vertical launcher or a trainable launcher that can accommodate these systems.
You recently pointed to an Israeli design equipped with such a launcher.
True, but if dealing with USVs, UAVs or small attack boats as seen in the Persian Gulf, the fire and forget mode would be most useful.
It is the versatility of JAGM that is it’s biggest strength. It is a very versatile weapon.
Yes, JAGM would give us more capability than the early model Hellfires but they are new, expensive, and relatively rare. The Coast Guard tends to be at the end of the line when getting new weapons. At least the early Hellfires would give us a greater capability and as they become available, JASM can be added to the mix.