[gocard14]

Ukraine has taken credit for the USV attack on the Russian Black Sea fleet.

https://www.yahoo.com/news/ukrainian-mad...00899.html



Unfortunately the relatively small warhead carried by these vessels is unlikely to do significant damage to a warship. Their warhead is about the same size as a lightweight torpedo (like the Mark 54). This kind of weapon is effective against a surface vessel only if it targets the screws/rudder area but otherwise, as they say, it "just scratches the paint". These USVs appear unable to do that. IMHO it might have been wiser for Ukraine to do a bit more development and make them acoustic homing weapons so they could wreck the propulsion systems. Otherwise, kind of wasted.

I don't see the source for saying the warhead is about the size of a lightweight torpedo.

There are analysis on the web discussing the USV that previously washed up on the shore of Crimea. Based on it's appearance and relative size, there is pretty compelling evidence that the ones used in this attack were the same kind. The estimate is that a 100 to 200 lb warhead was about the maximum it could carry.

There were two versions of a pre-dawn video from the shore showing what appeared to be a very large explosion (both versions apparently from the same webcam).  Would that be this warhead that is ineffective on a surface vessel?  Also, there was a daytime video showing an isolated explosion in the Sebastopol harbor (with helicopter nearby) - same explosion as at the end of one of the videos linked in this thread.  The camera was about 2 miles away from the explosion (10 seconds until the boom) and local car alarms can be heard.  That seems bigger than a small warhead.  (Note, it wasn't clear whether this video was of a previously found USV that was towed out to be destroyed, or part of the drone attack.  I suspect the former so maybe it was added explosives to destroy the USV.)

100 lbs of explosive going off in the open makes a very big boom. For comparison an M107 155 mm HE shell contains 18.6 lbs of explosive. Very difficult to tell from a video of this type what the weight would be. The analysis based on buoyancy gives a more realistic limit. It also depends on where the warhead is carried. You want it near the front but that creates balance issues.

Unlike torpedos, these USVs don't go running around at 55 knots. For comparison, a MK-48 "heavyweight" torpedo weighs 3600 lbs and carries a 647 lb warhead. However, it doesn't even hit the ship. It goes under it and shatters the keel.
https://www.defensenews.com/naval/2018/0...eel-video/
The torpedo explodes under the ship in in-compressible water, creating a "water hammer". It literally shatters the ship, as you can see in the video. 
The USV can't do that because it's warhead is too small and it can't get under the ship. What it could do is destroy the rudder or screws. Otherwise, it won't do much. It is actually surprisingly difficult to sink a warship by making holes in it's side. You need a big warhead and you need to have it explode inside the target, not on contact.

I don't understand why one would want acoustic homing devices.  The USVs were clearly being steered by someone watching the video, but perhaps clumsily.  I presume that whatever units were involved in designing & building & executing this attack had people that knew where they wanted to strike the vessels.    (Would acoustic homing work against docked ships?  I doubt these USVs have much chance against the ships in motion.)

The acoustic homing device would not work on a docked ship. The Project 11356R frigate in the video dabigv13 posted was clearly under way. The infrared portion shows the exhaust stack glowing and she has a bone in her teeth. The acoustic homing would allow the USVs to home in on the screws. This may require the USV to speed up to catch the target, which undoubtedly would strain it's capabilities and can't be sustained for long. Manually steering it to do this would be difficult, especially with data link delay and the fact the ship is much narrower that it is long :-). Acoustic homing is reliable and ensures you hit the vulnerable part, not two meters away. With a small warhead, you need all the help you can get. Otherwise you get a big boom and lots of scared Russians, but not much damage.
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I'm not sure that there is anything new in this report about US deliveries of NASAMS.  It does say that Raytheon delivered two to the US a few weeks ago, due to be in Ukraine by end of November.  It also indicate the US provided 1400 Stinger MANPADs.

Given the level of destruction in Ukraine I would have hoped for a more rapid response all along the line to the delivery of the NASAMS. No idea why it will take a month to get it there. IMHO this seems excessive, especially given the need.

A couple thoughts:

While a 200 pound warhead may not sink a ship, may not punching a hole in the side be sufficient to put it in dry dock for months of repairs, essentially removing it from the conflict?

Secondly, my impression has always been that the damage often comes less from the warhead and more from the fires caused by said warhead. Case in point, it only took 2 330 pound Neptune warheads to sink the Moskva, likely due to damage caused by the subsequent fires.

I also tend to agree that if the ships involved got off with light or no damage, the Russians would be posting video/photo evidence to proclaim the Ukranians ineffective.

[gocard14]

Ukraine has taken credit for the USV attack on the Russian Black Sea fleet.

https://www.yahoo.com/news/ukrainian-mad...00899.html



Unfortunately the relatively small warhead carried by these vessels is unlikely to do significant damage to a warship. Their warhead is about the same size as a lightweight torpedo (like the Mark 54). This kind of weapon is effective against a surface vessel only if it targets the screws/rudder area but otherwise, as they say, it "just scratches the paint". These USVs appear unable to do that. IMHO it might have been wiser for Ukraine to do a bit more development and make them acoustic homing weapons so they could wreck the propulsion systems. Otherwise, kind of wasted.

I don't see the source for saying the warhead is about the size of a lightweight torpedo.

There are analysis on the web discussing the USV that previously washed up on the shore of Crimea. Based on it's appearance and relative size, there is pretty compelling evidence that the ones used in this attack were the same kind. The estimate is that a 100 to 200 lb warhead was about the maximum it could carry.

There were two versions of a pre-dawn video from the shore showing what appeared to be a very large explosion (both versions apparently from the same webcam).  Would that be this warhead that is ineffective on a surface vessel?  Also, there was a daytime video showing an isolated explosion in the Sebastopol harbor (with helicopter nearby) - same explosion as at the end of one of the videos linked in this thread.  The camera was about 2 miles away from the explosion (10 seconds until the boom) and local car alarms can be heard.  That seems bigger than a small warhead.  (Note, it wasn't clear whether this video was of a previously found USV that was towed out to be destroyed, or part of the drone attack.  I suspect the former so maybe it was added explosives to destroy the USV.)

100 lbs of explosive going off in the open makes a very big boom. For comparison an M107 155 mm HE shell contains 18.6 lbs of explosive. Very difficult to tell from a video of this type what the weight would be. The analysis based on buoyancy gives a more realistic limit. It also depends on where the warhead is carried. You want it near the front but that creates balance issues.

Unlike torpedos, these USVs don't go running around at 55 knots. For comparison, a MK-48 "heavyweight" torpedo weighs 3600 lbs and carries a 647 lb warhead. However, it doesn't even hit the ship. It goes under it and shatters the keel.
https://www.defensenews.com/naval/2018/0...eel-video/
The torpedo explodes under the ship in in-compressible water, creating a "water hammer". It literally shatters the ship, as you can see in the video. 
The USV can't do that because it's warhead is too small and it can't get under the ship. What it could do is destroy the rudder or screws. Otherwise, it won't do much. It is actually surprisingly difficult to sink a warship by making holes in it's side. You need a big warhead and you need to have it explode inside the target, not on contact.

I don't understand why one would want acoustic homing devices.  The USVs were clearly being steered by someone watching the video, but perhaps clumsily.  I presume that whatever units were involved in designing & building & executing this attack had people that knew where they wanted to strike the vessels.    (Would acoustic homing work against docked ships?  I doubt these USVs have much chance against the ships in motion.)

The acoustic homing device would not work on a docked ship. The Project 11356R frigate in the video dabigv13 posted was clearly under way. The infrared portion shows the exhaust stack glowing and she has a bone in her teeth. The acoustic homing would allow the USVs to home in on the screws. This may require the USV to speed up to catch the target, which undoubtedly would strain it's capabilities and can't be sustained for long. Manually steering it to do this would be difficult, especially with data link delay and the fact the ship is much narrower that it is long :-). Acoustic homing is reliable and ensures you hit the vulnerable part, not two meters away. With a small warhead, you need all the help you can get. Otherwise you get a big boom and lots of scared Russians, but not much damage.
------

I'm not sure that there is anything new in this report about US deliveries of NASAMS.  It does say that Raytheon delivered two to the US a few weeks ago, due to be in Ukraine by end of November.  It also indicate the US provided 1400 Stinger MANPADs.

Given the level of destruction in Ukraine I would have hoped for a more rapid response all along the line to the delivery of the NASAMS. No idea why it will take a month to get it there. IMHO this seems excessive, especially given the need.

A couple thoughts:

While a 200 pound warhead may not sink a ship, may not punching a hole in the side be sufficient to put it in dry dock for months of repairs, essentially removing it from the conflict?

Secondly, my impression has always been that the damage often comes less from the warhead and more from the fires caused by said warhead. Case in point, it only took 2 330 pound Neptune warheads to sink the Moskva, likely due to damage caused by the subsequent fires.

I also tend to agree that if the ships involved got off with light or no damage, the Russians would be posting video/photo evidence to proclaim the Ukranians ineffective.