On April 18, 2023, the Turkish armed unmanned surface vessel (USV) “MIR” fired a light torpedo from a double torpedo tube at the stern of the ship. The test firing was the first torpedo launch from a Turkish USV.
This is offered as an ASW system, but if you are a regular reader here, you know I had to show the photo to illustrate how even a very small vessel can launch light weight torpedoes. (Of course, we have had previous examples, see photos at the end of the post.)
This is important because the Coast Guard has an unaddressed Required Operational Capability implicit in its Ports, Waterways, and Coastal Security Mission, that the Coast Guard needs to be able to forcibly stop any vessel regardless of size. A lightweight torpedo that targets a ship’s propeller(s) seems to be the best solution for stopping larger vessels (hopefully without sinking it and causing a major pollution incident).
Existing lightweight ASW torpedoes, like those launched from the USV illustrated above, might do the job if they also have an anti-surface capability. Distribution to Coast Guard units might be thought of as a storage option for a war reserve, in that, while the Coast Guard would need to have them widely distributed, even in the worst case the Coast Guard would actually use very few.
The author notes,
“…submarines are unlikely to engage these small units because of the limited minimum depth of some torpedoes or the limited amount of torpedoes the submarines have loaded.”
But if USVs become a threat to submarines, it will not be long before there is a counter. In fact, the already existing 6.75″ diameter (171.45mm), 220 pound (100 kilos), Very Light Weight Torpedo that would not displace any existing submarine weapons might anticipate this need. This weapon system might meet the Coast Guard’s needs.

A Navy briefing slide showing the internal components and describing the various features of the PSU_ARL Common Very Light Weight Torpedo (CVLWT) design

Camera drone’s-eye view of IRGC boats on display, March 2023. A) The air defense boat. B) Light missile boat with Bladerunner hull. C) light missile boats on Interceptor hull. D) light missile boats on Interceptor hull (alternative design). E) Missile boat, with type of missile unclear. F) RIB, possibly explosive boat or uncrewed. G) RIB with lightweight anti-ship torpedoes, can be carried aboard a Shahid Soleimani-class missile corvette. H) Interceptor boat. I) Interceptor boat with new type of missile.
The caption to the last photo says, “Elbit Systems’ Seagull unmanned surface vessel (shown firing a missile)” — um, isn’t a missile that travels underwater using propellers to hit underwater targets called a torpedo, rather than a “missile”? LOL
Thanks, I will correct that. That was the original caption.