I really like to see the results of SINKEX. They let you see how effective weapons are. I love them because they support my long held contention, that the way Coast Guard Cutters are armed, can provide us absolutely no confidence, we can reliably, forcibly stop anything larger than small ships.

The nearest thing we have had to a Coast Guard SINKEX did not end well. A firehose, it seemed, was more capable of sinking this poorly maintained, unmanned, derelict small vessel than our 25mm gun.

So far there have been two SINKEX exercises in this year’s RIMPAC. The video above is a series of attacks on the former USS Denver (LPD-9).The second video, below, shows attacks on the former USS Rodney M. Davis (FFG 60), a ship about 10% smaller than the Coast Guard’s new cutters (NSC and OPC), that took place on July 12.

The Drive describes the attacks on the former USS Denver. She was a medium sized ship, displacing about 17,000 tons full load, not huge by any means, but larger than most ships used in SINKEX.

 During the exercise,  the Japanese Ground Self-Defense Force fired Type 12 anti-ship missiles and the U.S. Army launched guided rockets from a High Mobility Artillery Rocket System (HIMARS) at the naval target from land. From the air, U.S. Navy F/A-18F Super Hornets assigned to Fighter Attack Squadron 41 shot a long-range anti-ship missile while U.S. Army AH-64 Apache helicopters shot air-to-ground Hellfire missiles, rockets, and 30mm guns.

From the sea, U.S. Navy guided-missile destroyer USS Chaffee (DDG 90) shot its Mark 45 five-inch gun. To top it all off, the U.S. Marine Corps joined in with F/A-18C/D Hornets assigned to Marine Fighter Attack Squadron 232 and Marine Air-Ground Task Force 7, who then fired an air-launched cruise missile, air-to-ground anti-radiation missiles, and Joint Direct Attack Munition guided bombs. Other weapons were likely used, but these were the ones disclosed by the Navy.

The smaller, 4100 ton, USS Rodney M. Davis (FFG 60), also did not go down easily. In addition to being hit by laser guided bombs and probably other weapons, she was hit by at least four anti-ship cruise missiles, two Harpoon from Canadian frigate Winnipeg, one from a P-8 maritime patrol aircraft, and a French-made Exocet Block 2 from Royal Malaysian Navy Kasturi-class frigate KD Lekir (F-26).

The two SINKEX were somewhat unique, in that they did not require a torpedo to finish sinking the ships, as has occured in almost every previous SINKEX.

It is true that the Coast Guard is more concerned about stopping ships than sinking them, but getting a mobility kill is very difficult. First the propulsion systems take up a relatively small part of the length of the ship and more importantly, most of it is below the waterline. Unless you can hole the engineroom hull below the waterline, forcibly  stopping a ship is almost impossible.  Killing steering is similarly difficult. If the target is shooting back, it gets much more difficult.

What Does It Take to Sink a Ship–the ex-USS Rentz Sink-Ex

Earlier I explored “What Does It take to Sink a Ship?” as a measure of what it takes to be absolutely sure you can stop one. Then the Japanese Tsunami gave us fishing vessel Ryou-Un Maru, a small vessel USCGC Anacapa attempted to sink with their 25mm gun. Anacapa ultimately resorted to coming along side and using a fire hose to fill the vessel with water, but it took over five hours.

Now the Navy provides us with information about another Sink-Ex. The former USS Rentz (FFG-46), a 4,200 ton, 453 foot long frigate, was the target. In spite of being hit by 22 missiles, she took five hours to sink. The last hit or hits were by Hellfire, and may not have been necessary, but not all the missiles were that small. The caption below appears to indicate at least two Harpoons were used.


Photo: US Navy. Guided-missile destroyer USS Benfold (DDG 65), foreground, and USS John S. McCain (DDG 56) fire Harpoons missiles as part of a sink exercise (SINKEX) during Valiant Shield 2016.

Reports also indicate that at least one JSOW C-1, an over 1000 pound guided gliding munition with both Infra-Red and Link-16 guidance, was used.

The caption on the photo below seems to indicate multiple AGM-65F were used. These are infra-red homing, Air to Surface Missiles, weighing over 600 pounds with a 300 pound warhead.

U.S. Navy sailors with Patrol Squadron 46 load a P-3 Orion aircraft with AGM-65F MAVERICKS Air to Surface Missiles prior to a sinking exercise (SINKEX) Sept. 13, 2016, at Andersen Air Force Base, Guam, during Valiant Shield 2016. SINKEX provided service members the opportunity to gain proficiency in tactics, targeting, and live firing against a surface target at sea. Valiant Shield is a biennial, U.S. -only field-training exercise with a focus on integration of joint training among U.S. forces. (U.S. Marine Corps photo by Sgt. Justin Fisher)

U.S. Navy sailors with Patrol Squadron 46 load a P-3 Orion aircraft with AGM-65F MAVERICKs, prior to a sinking exercise (SINKEX) Sept. 13, 2016, at Andersen Air Force Base, Guam, during Valiant Shield 2016.

When the video at the head of this post begins, it appears that the ship has already taken at least three major hits. I suspect these were two Harpoons and possibly the JSOW C-1. I suspect the four hits seen in the video were Mavericks launched from the P-8 that made the video.

The video below shows a Hellfire hitting what appears to be an already sinking hulk. It appears to me, the effects are clearly less than those seen in the video at the top of the post.

I would love to have a clearer idea of the sequence and effects of the individual hits, but one thing is clear. It took a lot of ordnance to put even this relatively small ship down. The Coast Guard’s 25 mm and 57 mm guns, with their five ounce and six pound projectiles, will not cut it.