The US Naval Institute News Service reports that in the second incident this month, Iranian Islamic Revolutionary Guard Corps boats again harassed US vessels in international waters in the Persian Gulf. (Earlier April 2nd incident reported here.)
At 8 p.m. local time on Monday, a trio of fast inshore attack craft belonging to the Islamic Revolutionary Guard Corps Navy (IRGCN) quickly approached Cyclone-class patrol coastal ship USS Firebolt (PC-10) and U.S. Coast Guard patrol boat USCGC Baranoff (WPB-1318), coming within 70 yards of the U.S. vessels operating in international waters, according to a statement from U.S. 5th Fleet.
“The U.S. crews issued multiple warnings via bridge-to-bridge radio and loud-hailer devices, but the IRGCN vessels continued their close-range maneuvers. The crew of Firebolt then fired warning shots, and the IRGCN vessels moved away to a safe distance from the U.S. vessels,” reads a Tuesday statement from U.S. 5th Fleet.
Unlike the earlier day light incident, this one happened in the early evening.
Chuck Hill's CG Blog 
The cutters are underarmed for these deployments.
Yes they are. But I would also say for this sort of work the boat itself is too small.
I would say something 250 to 300 tons with 30mm RWS for and aft.
Consider the Japan Coastguard Tsurugi-class
The Tsurugi-class are similar in size to the Webber class WPCs. There advantage is higher speed. The Japanese vessels are armed with a single 20mm Gatling Gun. In some respects the 25mm is better, although the 30mm version would be better still.
A pretty good review of the history of this sort of activity.
https://www.thedrive.com/the-war-zone/40348/irans-used-its-wacky-catamaran-to-cut-off-u-s-coast-guard-ships-in-the-persian-gulf
Let’s hope the Russian don’t sell them any ice strengthened cutters on hire purchase….
The FRCs destined for PATFORSWA are being up-armed with the addition of a Mk19 grenade launcher and Mk52 7.62mm chain gun.
https://blog.usni.org/posts/2021/03/26/u-s-coast-guard-prepares-for-further-deployment-overseas
All the recently built FRCs are getting the Mk38 mod3 with the coaxial 7.62mm. I don’t really think the Mk19 grenade launcher is an improvement over the .50 cal. The muzzle velocity is so low it makes it difficult to hit high speed targets.
I agree. There’s also the chance you can be hit by your own shrapnel if your round hits the water within 150ft or so of your vessel.
This seems to be related to the larger vessel involved in the harassment.
http://www.hisutton.com/Iran-IRGC-Catamaran-Update.html
I wonder why what drives their decision for silly and over complicated platforms that for the most part are just decoys and faux?
If I were them I would be building something simple and solid.
The IRGC is all about politics and domestic perception.
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Another harassment incident. https://news.usni.org/2022/12/06/iranian-patrol-boat-harasses-pair-of-u-s-warships-says-centcom?fbclid=IwAR1cfG7DKODAxGxhaGWxL_dp0mjnP7QfrtR4r4ca-M8uOAxNdLqhwX0C544