"The Biggest Boondoggle"???

Post a reply

Confirmation code
Enter the code exactly as it appears. All letters are case insensitive.

BBCode is OFF
Smilies are OFF

Topic review
   

Expand view Topic review: "The Biggest Boondoggle"???

Re: "The Biggest Boondoggle"???

by chuck » Tue Dec 09, 2008 4:01 pm

That might have been a significant distinction on a small ship, where the transient bubble from a torpedo explosion might replace water buoyancy over a signicient fraction of the hull. But I am not certain the transient air bubble formed by a torpedo explosion ever gets to be so large as to make it a significant distinction on a hull 42 meters wide. Considering WWII era torpedoes seem to destroy of battleship torpedo defense system in roughly 20 meter sections, I might guess that the transient air bubble of a torpedo warhead would be about 20 meters across. Also, under keel explosions, being deeper and subjected to greater water pressure, would produce smaller transient bubbles than torpedo warhead striking ship's sides. That will make it less than half as wide as a carrier hull, and replace perhaps 1/20 of the total water bouyancy under the ship's keel. I would not imagine that would hugely overload the hull girder. A carrier hull stuck in a deep trough between two waves is probably being bent by a much greater force than 1/15th of its normal buoyancy.

BTW, didn't the Tirpitz undergo several true underkeel explosions caused by mines deposited under her keel by British midget submarines? If I recall, those warheads were much bigger than typical torpedo warheads.

Re: "The Biggest Boondoggle"???

by Devin » Tue Dec 09, 2008 3:30 pm

chuck wrote:BTW, torpedo under the keel is not unknown from WWII. Yamato, for example, took a few under her keel when she was listing and thus presenting her bottom at an angle to incoming torpedoes. It exacerbated her flooding, but did not break her back, nor cripple her propulsion.
I would submit that those are not the same. Yamato took a torpedo IN her keel, not UNDER it. The difference is huge; akin to the difference between simply punching a two-by-four, or taking that same piece of wood and propping it up on two blocks and then punching it, as they do in karate demonstrations. The reason there is so much concern taken with keel blocks when a ship enters dry dock is that a ship's hull is not meant to be deprived of it's only support, the water underneath.

Now, how big of a warhead would you need to blow a "hole" in the water to buckle a carrier's hull? No idea, but it is indeed possible.

Re: "The Biggest Boondoggle"???

by chuck » Tue Dec 09, 2008 3:17 pm

MichelB wrote:In light of this discussion, wouldn't we love to see some info on the USS America sinkex? I can imagine they put some torpedoes under her keel... never will happen, I can imagine that info being as classified as it gets.
It will eventually come out after its relevance is passed, and it may even come out much sooner than that if it can be used to publicly support certain naval construction policy.

BTW, torpedo under the keel is not unknown from WWII. Yamato, for example, took a few under her keel when she was listing and thus presenting her bottom at an angle to incoming torpedoes. It exacerbated her flooding, but did not break her back, nor cripple her propulsion. The hull of modern carriers are significantly wider than Yamato's, and has much deeper girder structure thanks to the integral flight deck. So I would guess a modern carrier's resistance to major structural failure would be very great and no mere 21" torpedo is going to break the back of a CVN.

As to the issue of bomb damage, that does illustrate a more serious vulnerability, which is relatively little ordinance might be needed to put an end to a carrier's flight deck operations. Certain the flight deck accidents that befell the USN several times during Vietnam war suggests that a carrier can be incapacitated for hours or even days by just a few explosions on deck. But here the issue is a little more hazy because:

1. It's not all together clear that ASM's that get through will actually hit the carrier's deck, Most may just make holes on the skin of the carrier's hull. It's not clear how much buffer there is on the carrier's hanger side, whether the hanger side has any armor protection at all, and whether impact by a typical ASM is likely to do a lot of damage inside the hanger. The carrier is a much bigger ship than any warship that actually took an ASM hit for real. So the story of the HMS Sheffield and USS Stark might give an all together misleading impression of just what might happen if a medium sized ASM hits a carrier.

2. It's not all together clear how effective are the electronic countermeasures. Just how many ASMs that find its way near a carrier will actually hit?

Re: "The Biggest Boondoggle"???

by MichelB » Tue Dec 09, 2008 2:19 pm

In light of this discussion, wouldn't we love to see some info on the USS America sinkex? I can imagine they put some torpedoes under her keel... never will happen, I can imagine that info being as classified as it gets.

Re: "The Biggest Boondoggle"???

by bengtsson » Tue Dec 09, 2008 1:50 pm

What you said in your last post is right on the money Walt. :smallsmile: The USN has been more than impressed by foreign Diesel boat's abilities. You are also right that they have more of a local defense role. They are not about chasing a CV group around the high seas, that's a nuclear attack boat's role. The defence of areas of probable CV operation is their proper role. With their sonar, they can know pretty well what is going on up top. Their detection ranges are huge, allowing a silent approach to good ambush positions. Of course it isn't a sure bet every time. But sooner or later they will be able to get into a good attack position. They can choose either a torpedo attack if that presents itself, or a launch of anti shipping missiles.
It was common knowledge amoung sonarmen, that the hardest thing to detect was the Diesel Boat on batteries. And these modern boats aren't type VII Uboats. Things have improved alot, and no submariner or surface sonar technician I ever knew looked down the Diesel Boat.

Bob B.

Re: "The Biggest Boondoggle"???

by chuck » Mon Dec 08, 2008 11:15 pm

No, I have not thought of that. I have to go back and read it again.

Re: "The Biggest Boondoggle"???

by Timmy C » Mon Dec 08, 2008 10:09 pm

Chuck, if you are talking about the picture on page 118 with the note "Adapted from Hasegawa", have you ever thought that "Hasegawa" might refer not to the model company, but rather, to Hasegawa Toichi, author of Japanese Aircraft Carriers? Though the pictures are not given a reference note (that I can see), the reference to Toichi can be found for note 7 of page 119.

Re: "The Biggest Boondoggle"???

by Lesforan » Mon Dec 08, 2008 8:38 pm

Gee, Chuck,

From reading this Forum over the past several years I got the impression that "Shattered Sword" was so good and so accurate it negated all previous works' conclusions on The Battle of Midway. Nice to see that opinion is not universal.
I have not read the book, but the part about the plastic kit instructions being used as a reference source for an historical work is quite a revelation to me. (I was treated rather roughly by a professor in my freshman college year for attempting this very stunt in 1968. He was as impressed by the tactic as you are.)

Maybe this book is not inspired scripture after all. Maybe some conclusions about this battle I reached by reading other authors is not heresy after all. This (could) change everything.

Re: "The Biggest Boondoggle"???

by Walt » Mon Dec 08, 2008 5:30 pm

chuck wrote:
bengtsson wrote:Walt might agree with this. One reason the Carrier's own submarine screen and also the surface screen has SO much trouble detecting the attacking submarine is because the area around the Carrier group is as noisy as a Rock Concert. I mean underwater of course. In sonar Noise = lack of sonar performance. Now the attacker likes noise, lots of lovely noise! That is how he manages time and again to penetrate ASW screens. Myself, I have missed Soviet Subs due to the snapping shrimp. These little buggers sound like very loud frying bacon. Believe it or not, that is often time all it takes to foil passive sub sonar if a silent boat is near by. And a conventional boat on batteries is pretty silent.

Bob B.

A spherical sonar array pick sound up by its direction, the same with a submarine's towed array sonars. The directional resolution of the multi-hydrophone directional sonar is such that noise from one direction will not seriously obscure noise from another. Direction sonar would not be much bothered by white noise in the water so long is the white noise is coming from one direction and the submarine from another. So a ship or a submarine on the perimeter of a task group will be able to listen for a submarine coming in from the outside of the task group despite the louder noise coming from the task group itself.

Regarding the diesel submarine's silence, a diesel submarine can't go very far while silent, and the high underwater speed quoted for modern SSK is a short duration burst speed that could not be kept up for more than 20-30 NM. The real range of silent mobility of a SSK is very short compared to the distance at which a carrier's airgroup can strike. So unless the opponent is so lucky as to place a diesel right in the path of a carrier, the diesel boat can be as silent as she wish, she simply lacks the mobility to stand a high chance of intercepting the CVBG.
The whole premise of the modern SSK is defensive in nature. To patrol and defend coastal waters against other boats as well as skimmers..It's the weapons and weapons systems carried by the SSK that have the speed, range, accuracy and wallop to trash a CV from way...way down range. As a result of recent tests of loaned SSKs by the USN they are now seriously considering them for our own use. As for a Submarine's ability to mask itself, decoy and confuse it's hunters with various types of ECM, and decoys, speed and stealth you would be surprised what they have available to them to to initiate a first strike situation.
In a major engagement on the high seas today the winner will be the one who was quickest on the trigger. After the attack is launched by the Attack Submarine there will be plenty of noise to mask a high speed departure. In a match up of a CV and her escorts against one or several attack boats the Surface vessels are in deep trouble. The CV still has a major and important purpose in our Navy's inventory, especially in support of far off regions of the world that need support either in a humanitarian or amphibious operation. Power projection against a modern Navy that has a modern submarine force SSK or SSN is no longer one of them. Like the BB before them the CV has become a "BFT" big Fat target.

Re: "The Biggest Boondoggle"???

by bengtsson » Sun Dec 07, 2008 3:32 pm

Gone Asiatic wrote:
bengtsson wrote:Amazing! :smallsmile: And here we didn't even know that Carrier task groups were invulnerable to submarine attack. Funny that that wasn't taught at either Submarine Sonar School or Surface Sonar School at the Fleet ASW School in San Diego :cool_2:

Bob B.
The OOUUTTRRAGE!

The Fling was a great place for a beer or two, as was the Lost Paycheck across the street.
:big_grin:
Hey man! I was in the Navy for almost 4 years before I reached legal drinking age! :big_grin: The bars were off limits for us kids. Got arrested for underage drinking 3 weekends in a row while doing my year and a half at sub sonar courses at Fleet ASW School. Had friends buy us bottles at the liquor stores on Rosecrans street and either threw them over the fence to collect later or drank up on the hill overlooking NTC. Anyway you cut it, the San Diego Police and the Barracks MAA both took our being hammered very seriously :heh:


Chuck. I agree, getting at a USN Carrier Force is no easy task. I only maintain it can be done, and has been done by our own submarines. I can't speak for foreign sub forces. Passive sonar is indeed directional, very much so. My point is that there are vulnerable areas, and the closer you get the louder and more disturbed the water. It is always far, far easier for the sub to know where the Carrier group is and to plot where it is going. Making ambush alot easier. There is a reason the USN went to using our own Nuclear Subs as Carrier escorts. That was the proven ability time after time of USN subs getting inside the ASW screen.

I also see the advent of the sub launched super sonic anti shipping missile as a "Game Changer". Attacks from over the horizon are now possible, and on limited fire control data. Simply my opinion that :wave_1: But it isn't my Navy any more, getting in close to deliver a torpedo isn't the only option.

Bob B.

Re: "The Biggest Boondoggle"???

by chuck » Sat Dec 06, 2008 11:01 pm

bengtsson wrote:Amazing! :smallsmile: And here we didn't even know that Carrier task groups were invulnerable to submarine attack. Funny that that wasn't taught at either Submarine Sonar School or Surface Sonar School at the Fleet ASW School in San Diego :cool_2:

Bob B.
For the sake of your morale, they had to protect your ego from being trampled upon by reality. :big_grin: :big_grin:


Okay, let's not argue from extreme positions here. What I am saying is the difficulties involved in any other power using a plausible submarine force to prevent US carrier task force from carrying out most missions is very large, and large enough to make one assume that the carrier will remain effective as both an instrument of peacetime policy and as instrument of various levels of war for long enough to justify building new carriers.

I said nothing about whether the US submarine fleet, equipped with far more nuclear submarine than anyone else, and benefiting from a unique system of global operational intelligence assets and global communication network, can not inflict serious casualties upon a US carrier task force.

I am not even saying that a third power, equipped with plausible submarine fleet and supporting assets, have no chance of inflicting serious casualties upon US carrier force.

What I am saying is US carrier forces, equipped with supporting assets no available or expected, stands a much better chance of being able to accomplish it mission against a hostile third power equipped with a plausible submarine force and supporting assets in the near future.

Re: "The Biggest Boondoggle"???

by Gone Asiatic » Sat Dec 06, 2008 8:52 pm

bengtsson wrote:Amazing! :smallsmile: And here we didn't even know that Carrier task groups were invulnerable to submarine attack. Funny that that wasn't taught at either Submarine Sonar School or Surface Sonar School at the Fleet ASW School in San Diego :cool_2:

Bob B.
The OOUUTTRRAGE!

The Fling was a great place for a beer or two, as was the Lost Paycheck across the street.
:big_grin:

Re: "The Biggest Boondoggle"???

by bengtsson » Sat Dec 06, 2008 1:04 pm

Amazing! :smallsmile: And here we didn't even know that Carrier task groups were invulnerable to submarine attack. Funny that that wasn't taught at either Submarine Sonar School or Surface Sonar School at the Fleet ASW School in San Diego :cool_2:

Bob B.

Re: "The Biggest Boondoggle"???

by chuck » Fri Dec 05, 2008 11:53 pm

Filipe Ramires wrote:
Akagi was crippled by one single bomb hit according to the latest studies.
Akagi's latest studies consist of one (1) study by one very opinionated person who wrote the "shattered sword". His research on the internal layout of Japanese carriers, upon which he based so much of his theory, consisted at least in part of buying a 1/700 scale plastic model of Japanese carriers and reading the sketch diagrams that came with its instructions. So reliable did he regard this source of evidence that he even reproduced that diagram, properly credited to the plastic model manufacturer, in his book, as evidence.
Filipe Ramires wrote: Ark Royal was sunk by one single submarine torpedo.
Wasp turned into pyros when hit by two submarine torpedoes...nearly impossible to save.
So what? They were both fairly small carriers roughly comparable to heavy cruisers in full load displacement. Consequently their underwater damage resistance should be expected to be about the same as that of a heavy cruiser. And indeed their performance is right in line with what one expectes from a heavy cruiser of about 18,000 tons.

We can also extrapolate from their performance, and performance of other warships of the era, roughly how many total torpedo hits on both sides ships with of different full load displacements, outfitted with WWII standard damage control, can on average be expected to survive.

15,000 tons 1-2 torpedoes

30,000 tons: 3-4 torpedoes

40,000 tons: 6-7 torpedoes

50,000 tons: ~10 torpedoes

70,000 tons: >15 torpedoes

From this we might extrapolate that a modern super carrier of about 100,000 tons can withstand many torpedoes hits indeed.


As to ships being broken in halves by underkeel explosion, keep in mind that all the spectacular photos of target ships broken in half are on ships with light construction and longitudinal framing. In other words ships whose hull is built like an airplane fuselage, with all the load paths on the ship's skin. All modern cruisers and destroyers are built like this. But heavy carriers? AFAIK, they are still built with transverse framing with multiple internal load path, rather like battleships. In this case I see no reason at all why they would be particularly susceptible to massive structure failure resulting from an moderate sized underkeel explosion.

Re: "The Biggest Boondoggle"???

by chuck » Fri Dec 05, 2008 11:35 pm

bengtsson wrote:Walt might agree with this. One reason the Carrier's own submarine screen and also the surface screen has SO much trouble detecting the attacking submarine is because the area around the Carrier group is as noisy as a Rock Concert. I mean underwater of course. In sonar Noise = lack of sonar performance. Now the attacker likes noise, lots of lovely noise! That is how he manages time and again to penetrate ASW screens. Myself, I have missed Soviet Subs due to the snapping shrimp. These little buggers sound like very loud frying bacon. Believe it or not, that is often time all it takes to foil passive sub sonar if a silent boat is near by. And a conventional boat on batteries is pretty silent.

Bob B.

A spherical sonar array pick sound up by its direction, the same with a submarine's towed array sonars. The directional resolution of the multi-hydrophone directional sonar is such that noise from one direction will not seriously obscure noise from another. Direction sonar would not be much bothered by white noise in the water so long is the white noise is coming from one direction and the submarine from another. So a ship or a submarine on the perimeter of a task group will be able to listen for a submarine coming in from the outside of the task group despite the louder noise coming from the task group itself.

Regarding the diesel submarine's silence, a diesel submarine can't go very far while silent, and the high underwater speed quoted for modern SSK is a short duration burst speed that could not be kept up for more than 20-30 NM. The real range of silent mobility of a SSK is very short compared to the distance at which a carrier's airgroup can strike. So unless the opponent is so lucky as to place a diesel right in the path of a carrier, the diesel boat can be as silent as she wish, she simply lacks the mobility to stand a high chance of intercepting the CVBG.

Re: "The Biggest Boondoggle"???

by bengtsson » Fri Dec 05, 2008 7:25 pm

Walt might agree with this. One reason the Carrier's own submarine screen and also the surface screen has SO much trouble detecting the attacking submarine is because the area around the Carrier group is as noisy as a Rock Concert. I mean underwater of course. In sonar Noise = lack of sonar performance. Now the attacker likes noise, lots of lovely noise! That is how he manages time and again to penetrate ASW screens. Myself, I have missed Soviet Subs due to the snapping shrimp. These little buggers sound like very loud frying bacon. Believe it or not, that is often time all it takes to foil passive sub sonar if a silent boat is near by. And a conventional boat on batteries is pretty silent.

Bob B.

Re: "The Biggest Boondoggle"???

by Filipe Ramires » Fri Dec 05, 2008 2:30 pm

Dick J wrote:1. In the 1930's, all of the wargames expected a carrier to be totally incapacitated by just two bomb hits and sunk by anything more. WW-II proved the CV's to be far tougher than ANY pre-war estimates - and not just the armored deck types. Bombs and torpedoes rarely did as much damage as they had been expected to. As was mentioned, only when a CV is put on the bottom will we know how vulnerable they really are. Until then, it is just your best guess.
Akagi was crippled by one single bomb hit according to the latest studies.
Ark Royal was sunk by one single submarine torpedo.
Wasp turned into pyros when hit by two submarine torpedoes...nearly impossible to save.

Weapons might not be that dangerous but what good is a ship without proper damage control parties; with the flight deck pierced by one bomb and therefore without further capability of landing or taking off operations; with her vitals damaged to the point that not even the best damage control parties can save her. There are cases in WWII that carriers took a lot of punishment and survived...other cases just show how very little is needed to take a carrier to the bottom.
Dick J wrote:2. Today's torpedoes are NOT that much more powerful (if at all) than the WW-II types. They ARE better at detonating below the keel, and that is why they are more effective. WW-II attempts to detonate there were significantly less than successful. However, I am not aware of any under-the-keel tests actually being conducted on a maneuvering target. Again, only a CV on the bottom will prove the effectiveness. Until then, this is just another best guess.
True about moving or even evading sitting duck targets. However, one thing is to be hit, nearly at waterline level, by one torpedo...you can still do some damage control and with proper counter-flooding correct the listing of the ship. The ship is disabled in any case. Any warship taking a torpedo hit is off the fleet for repairs...it is unwise to keep a torpedo hit ship around. A ship taking a torpedo hit below the keel, depending of course of what kind of ship it is, it will most likely break in two...with that scenario little can be done by damage control parties. Perhaps a carrier will not break in two but again it will be disabled and off from operations and to spend quite a few weeks in a dry-dock for repairs. WWII torpedoes were meant to punch holes on the sides of the ships and let the water in and therefore going to the bottom with the extra weight. Torpedoes today not only do that but inflict far more dangerous structural damage. Structural damage kills the integrity of any surface ship or submarine.
Dick J wrote:3. Post WW-II, the CV was considered to be dead until the Korean War showed that they were the best source of tactical air support in that conflict. The Air Force had lost all their bases within tactical range and it was not considered politically correct to "save" South Korea by nuking it. While it is true that there are no significant navies to fight, the CV's real mission has been power projection ashore ever since 1950. That mission has NOT gone away.
With this I completely agree like I said in a previous post of mine. Carriers can do things that a submarine cannot therefore they are still the best means for conventional power projection.

Re: "The Biggest Boondoggle"???

by Filipe Ramires » Fri Dec 05, 2008 2:10 pm

chuck wrote:Hmmm, You must be vacationing on a planet over 6 light years away from Earth. It appears that information about Iraq, traveling 6 years at speed of light, have not yet reached you. :wave_1: :wave_1:
Actually I wouldn't mind taking my holidays in some tropical planet light years away but again even Space Race investments are a bit down today!!! The situation on Iraq I am well aware but we are speaking of a kind of saturation war or occupation of hostile territory...classic in any late or post war occupation of enemy territory. Military want and are needed in Iraq for certain...politicians are not that certain and like this professor and their own kind think they would drop Iraq in one minute notice if they could. Keeping a war is never a good thing for a politicians career...it is actually political suicide...regardless the costs that it might have. What's going on in Obama's mind regarding Iraq or Afghanistan or any other potential conflicts looming up in the horizon!?!?!?!

Re: "The Biggest Boondoggle"???

by Walt » Fri Dec 05, 2008 1:29 pm

Jack Ray wrote:Speaking of exercises, does anyone have any idea how effective ASW is in exercises? Are sub hunting techniques effective?

Jack
Jack,I do believe that they are very effective..as a reaction not a proactive defence unless given prior warning of a aggressor subs proximity.

Due to the nature of the hunt the Submarine usually always knows where it's hunter is. Unless of course it's another Sub.. Then it's much like blindman's bluff.. Both become the hunter as well as the hunted. The passive nature of a submarines counter measures and offensive weapons systems is also it's advantage. The hunter is most usually in a "Active" search mode giving the hunted much warning and location etc. SSN's by their design are expendable.. It's the damage they can render a surface target before they are discovered or located that make's them so darn bad... During several hunt and kill exercises I experienced while I was on a boat we always got in the first punch and most othertimes several more shots before being cross haired by a ASW operator.. That is plenty in a real time situation.
The modern SSN is light years ahead of anything I had experience with as well as it is for today's ASW, but the advantages still lay with the Hunter. And I'll wager that today as it was in the past the Submarines worse nightmare is another Submarine. And a CVN's best friend as well as biggest fear is a frendly or bad guy Submarine:big_grin:

Re: "The Biggest Boondoggle"???

by Jack Ray » Fri Dec 05, 2008 12:24 pm

Speaking of exercises, does anyone have any idea how effective ASW is in exercises? Are sub hunting techniques effective?

Jack

Top