It’s obvious from the
preceding post (see, "Fitzgerald Collision") that there is a lot of misguided and incorrect thought out there
about ship size and the impact of armor on a ship’s performance. I’m reading consistent statements that modern
ships can’t bear the weight of armor without seriously impacting endurance,
range, and speed. That’s just absolute
bilgewater and betrays a lack of knowledge about previous ship designs – WWII,
in particular. So, to help put ships and
armor into an actual and factual context, let’s look at WWII ship designs
versus today.
In the following discussion,
I’m going to generically refer to “armor” as the total of hull plating and any
add-on armor that may have been present.
Here’s the relevant
specifications for the Burke class DDG.
Burke Class Flt IIa
Length 509 ft
Displacement 9200 t
Range 4400 @ 20 kts
Speed 30+ kts
Armor 5/8” – 7/16” hull plating, 7/16” – 1/2” deck
(1); no additional external armor
Now let’s look at some WWII
designs.
Length 610 ft
Displacement 10,000 t
Range 13,000 @ 15 kts
Speed 33 kts
Armor “The ships were completed with belt armor 5
inches thick over the magazines and 3.25 inches elsewhere. Armored bulkheads were between 2 inches and
5.75 inches, deck armor was 2.5 inches, the barbettes were
1.5 inches, the gunhouses were 2.5 inches, and the conning tower was
1.25 inches …” (2)
We see that the Portland
Okay, you say, a large
cruiser could carry armor but how about a smaller ship – a ship the size of, or
smaller than, a Burke? How about the
Fletcher class destroyers?
Fletcher Class Destroyer (4)
Length 376 ft
Displacement 2500 t
Range 5500 @ 15 kts
Speed 36 kts
Armor 1/2” – 3/4” hull and deck
The Fletcher class, much
smaller than a Burke, had its thinnest plating equal to the Burke’s thickest
and had heavier, thicker 3/4” plating in many locations, in addition. So, the Fletcher, despite being significantly
smaller than a Burke, carried more armor and had as good range and speed. I guess WWII ship designers didn’t realize
this was impossible.
Let’s take a look at one
more, the Atlanta
Length 541 ft
Displacement 7400 t
Range 8500 @ 15 kts
Speed 33 kts
Armor 1.1” – 3.5” belt, 1.25” deck (3)
Hmm …….. Yet another example of a ship slightly longer
than the Burke, significantly lighter, and yet has larger amounts of armor,
greater range, and equal speed. I guess
WWII ship designers didn’t realize this was impossible.
I can go on with example
after example but the point is made. For
a properly designed ship, there is no range, endurance, or speed penalty. Those who believe that modern ships can’t
carry armor without significant performance penalties are just ignorant of what
was common practice decades ago. Every US
There is no reason not to
armor our ships commensurate with their size and purpose.
________________________________
(1)Unpublished cross
sectional construction drawing for Burke class
(2)Wikipedia, retrieved 21-Jun-2017 ,
(3) Wikipedia, retrieved 21-Jun-2017 ,
(4)United States
There is a wrongheaded mentality now in ship design, "We only want what is high tech and new". Thick steel is old fashioned, therefore obsolete and we don't want it. Back in February I attended the American Society of Naval Engineers national convention as a student member. (40 year old student, former sailor). This tech obsessed mentality was everywhere. Speakers were all giddy about Ford, Zumwalt, and LCS. Terms like "war fighters" were used without consideration of what really happens in war. Virtually no discussion on damage control or ship survivabililty; they just assume with all the latest and greatest high tech, they'll never get hit. Sorry, but war is chaos and you will take a hit at some point. Seems to me that money is driving a lot of the thinking. Picture a university research lab developing solutions looking for problems in order to keep the grant money flowing. There's no profits in simply using thicker steel.
ReplyDeleteLove this blog, let's me know I'm not alone.
MM-13B
I wonder how difficult it would be to just build an older ship modified to accommodate newer electronics. Remove a gun turret and it's associated machinery and make that space available. Remove all the secondary armament and add some cwis and rams in their place as well. You might actually get some weight savings.
ReplyDeleteAndrew, that was my thought on how to build an effective LCS type ship. The WWII destroyers were fast and shallow draft, and they did plenty of real combat in littoral areas. Take that basic hull and modernize it as you suggested. But that would be too cost effective. Instead we ended up with expensive useless junk, and now they'll need more funding to fix the shortcomings.
DeleteMM-13B
Tend to agree with every post here one need not forget those lightly armored ships that were brought back over the years what was their name ahh yes the Iowa class I think they had a little armor but could run around at 30+ knots I believe yep those designers didn't have any idea at all what they were doing or building for that matter now we design and build "expendable" ships ala LCS which can't do a damn thing good
Deletecareful what you ask for with those 'older ships'. Stability by modern standards would be terrible, heavy boilers and steam turbines just arent made anymore yet they had weight low in the hull which enabled a narrow beam and allowed a fast speed. Electronics and cooling plant adds weight higher up which means beam is increased to maintain stability that means top speed drops- which is a good thing in many ways.
DeleteFletchers with 4 boilers could go well over 30 knots, but for practical purposes using only 2 at a time would give you up to 28 kts, which was the most you ever needed.
Good story here from a civilian maritime student who got 'press ganged' into navy at graduation and served aboard a Fletcher class in the mid 50s'
http://www.navyhistory.org/2013/07/life-on-a-fletcher-class-destroyer-1950s/
He may have not wanted to join the navy but left as a Captain!
As an experienced ship designer, I can tell you that any of that is possible - IF you are willing to obey all of the laws of physics ("Oh, you want cooling for those electronic goodies, too?"), and IF you are willing to throw out several tons of paper written since WWII on habitability standards, and .... Just tell the ship designers what changes are legal and what aren't. And then find enough admirals and Congress critters to support them.
DeleteThat depends on if you mean 'build a ship /inspired by/ a previous ship' in idea, concept, ability, or whatever; or literally take the WW2-era plans and build them again with slight changes.
DeleteIf the former, most certainly. A modern missile-slinging Atlanta-in-spirit would be an excellent replacement for the Ticonderoga-class, and I would wholeheartedly support this move.
If the latter (and I suspect this is what you meant)... well, Alan Gideon has it completely correct. Only some of the old designs could possibly support that, such as the Iowas, and even then they would have dozens of problems.
Would you believe that I have actually had commanding US Navy personnel inform me that the two reasons why the Iowas are not reactivated today (this was in 2015) are:
1) "They do not fit our desired appearance, they are too 'scary' and that makes us look like the bad guys. We want ships that look friendly and can put on a good face, not ships that look like they are designed to kill you and your mother for daring to look at them wrong."
and
2) "We can't figure out where to put the women's berthing and restrooms."
As a patriotic American who loves his navy, the first one had my blood boiling, as 'ships that look like they are designed to kill you and your mother for daring to look at them wrong' would be a really useful asset. As someone who used to study ship design (academic only), the second thing made me want to faint. Primarily because women in general cannot handle the blast overpressure of the 16in guns firing that hits the entire ship and studies proved this in the 1980s after one of the female Dahlgren workers was injured during a test firing when she was in one of the deepest parts of the ship (the fire control room, nonetheless), so the reasons this officer (who was associated with the then CNO) provided me amounted to Glitter and Social Justice - neither of which are war winners, both of which are war losers.
In the end, that is the primary reason why we do not have heavy, armored, well armed war-fighting ships with the express purpose of being 100% capable of making the other guy die for his country so that his country won't bother fighting us in the first place: Glitter and Social Justice.
- Ray D.
Ray, another good comment! This goes to my oft repeated theme that we've forgotten what war is. War is a hideous, ugly, brutal affair. The Navy exists to win wars and wars are won by killing the enemy in large quantities and in the most efficient manner possible and by destroying all his means of making war. Our Navy has forgotten why it exists.
DeleteI have stayed away from criticizing the Burkes for 2 reasons 1tbey actually work 2 I don't know enough bout ship design or armor etc to comment except that hull ain't thick enough
ReplyDelete"they actually work"
DeleteWhat do you base that on? They've never been in combat so how do we know they work?
The closest they've been is when the Port Royal ran aground and wound up severely damaged from a gentle grounding and when the Cole suffered the terrorist explosion and was badly damaged from an EXTERNAL explosion and now this collision with the container ship and almost sank. That's not a ringing endorsement of the Burke class combat toughness.
The only other combat type of incident was the ship that fired some missiles at what they though was incoming anti-ship missiles and not only could they not verify they hit anything, they couldn't even say for sure that missiles were actually incoming!
All in all, the scant evidence we have suggests that these ships are not going to be hugely effective in combat.
If you have some other reason to believe the Burkes "work", please tell me.
Minor quibble: the Port Royal isn't a Burke.
DeleteQuibble away! My bad! That's why I have sharp readers to keep me on my toes.
DeleteI was trying to illustrate the fragility of the Aegis radar system and the alignment problems of the radar and VLS which were both damaged from gently rocking. The Burke has a similar radar system and VLS so I suspect they would be equally susceptible. Maybe we should gently run a Burke aground and see what happens!
No need to run aground an actual ship, they can simulate it on their computers! Joking aside bottom of the hull damage is one of the worst areas to fix up, even from an access point of view. While the sides of the hull keep the water out, the bottom supports the whole weight
Delete"bottom of the hull damage"
DeleteThe Port Royal was not damaged on the bottom of the hull - at least not significantly. What was damaged was the alignment of the Aegis radar arrays and the VLS cells from the gentle rocking while the ship was grounded. All evidence suggests that the Navy was unable to repair those which is why they initially tried to retire the ship.
This comment has been removed by a blog administrator.
ReplyDeleteHuh??? I didn't understand a word of that comment or what point you're trying to make. Want to try again?
DeleteI'm sorry but I still have no idea what point you're trying to make.
DeleteAnon:
DeleteNavy ship building is very conservative and damage control and fleet logistics play a role in keeping the status quo. There are tremendous opportunities to improve the mass ratios of a new ship design to reduce the fraction of the total ship's mass allocated to hvac, chilled water, electronics, etc.
The following links are just a taste of what could be possible if the navy still had a functional design team and spent some money on test and development.
http://www.dtic.mil/dtic/tr/fulltext/u2/a473662.pdf
http://www.doerry.org/norbert/papers/20100325Energyandtheaffordablefuturefleet-final-1.pdf
The DTIC paper is very troubling to read. Many HVAC components have not been updated since WWII in current warships (some minor updates but little thought to a new standard architecture). Very poor efficiency, resulting in increased energy requirements and waste heat that needs to be removed.
The current ships appear to be little more than floating HVAC systems.
Modern ship design may be driven by volume, but the volume is dictated by the systems that are used. Using systems that are high volume, massive and inefficient increase the volume of the ships. The Navy should develop some new ship construction standards that take into account 60 years of progress and lightweight the hotel and equipment functions of the ships and devote mass to survival.
DeleteYou'll find that it's less the "inefficient" volume of the systems, but policies on access, removal routes and maintenance envelopes. Plus vastly increased habitability standards. Go below decks aboard a modern ship and compare it to a 60s/70s ship (let alone WW2) and the difference is obvious. Simple ergonomics also have an effect - compare your "average" size sailor now to one of 60 years ago - there's a bit difference in height and breadth and no, it's not about being fat!
Delete"point I'm making is that simplistic comparisons of deep displacement vs length and speed"
DeleteWho's comparing displacement versus length/speed? I didn't!
Anon, I still am failing to grasp whatever point you're trying to make. You seem to be saying that ships have different equipment now then during WWII. Okay ... so what? How does that affect the premise of the post that modern ships can carry armor without a performance penalty? Nothing you've said contradicts that nor even is related to it.
WWII ships had much more electrical generating equipment and HVAC than sailing ships. Again, what's your point?
Whatever point you're trying to make is incomprehensible. Tell me how your point, whatever it is, relates to the armor carrying capability of a modern ship. I'm on the verge of deleting your comments as incomprehensible.
In anon defense, I think he is trying to say that the majority of modern ship volume is occupied by electronics and the required equipment that sustains them.
DeleteThat being said, older designs have plenty of space to accommodate modern electronics and the equipment to sustain them. Multiple weapons, their associated ammo lockers and crew berthing can used to house them. Additional some main gun turrets aren't needed thus their associated magazines and crew berthing can also be used for that end.
Also the electronics themselves can modernized and made smaller by switching to digital.
Andrew, there's nothing to defend since I have no idea what his point is! If it's that modern ships are volume filled with electronics, as you suggest he's saying, that's patently absurd. Modern ships are filled with the same things they've always been filled with: berthing space, galley space, fuel storage, water storage, cold/perishables storage, magazines, firefighting equipment, chain lockers, spares storage, machine shops, engine rooms, damage control spaces and equipment ... do I really need to go on?
DeleteYes, there's also HVAC but that's not new. WWII ships had extensive ventilation.
Yes, there's electronics - more than WWII ships had but on a percentage basis, electronics make up a small portion of the total ship's volume.
There are also "things" that were present in WWII ships that aren't present on modern ships and, therefore, have freed up a lot of space: giant gun barbettes, huge magazines, large boilers and steam plants, many more numbers and types of weapons, etc.
So, all that said, I really can't fathom what anon's point is, if he has one. As I said, I'm going to wait a bit to see if he can explain himself a bit better and, if not, I'll delete the comments as incomprehensible.
I think I vaguely get what he means. He might be pointing out that the space that used to be for armor got taken up today by electronics and wiring and cooling tubes, so to get in more armor you need to upsize the ship, which in turn would mean more armor in a feedback loop.
DeleteI think....
I just had a disturbing thought with all the steel arguments. Why steel? It might be a 'Goldilocks' material now, not enough toughness yet does not give benefits of weaker materials, maybe.
The European navies seem to be heading towards radar absorbing plastics/fibres, which would not help in cases like the Fitz, but in a shooting war, giving enemy missiles a hard time locking on might be a serious lifesaver.
So might there be benefits to materials other than steel?
"the space that used to be for armor got taken up today by electronics and wiring and cooling tubes"
DeleteIf that's what anon means, he's just plain wrong. Armor is very thin on a relative basis and is applied, traditionally, on the outside (belts), outer layers (thicker plating), or bulkheads/decks in the form of a little added thickness. Electronics, wiring, and cooling ducting, in contrast, is mounted INTERNALLY in the open spaces of compartments. They do not take up space that armor would occupy!
There's nothing wrong with investigating other materials that may prevent weapon locks but to ignore armor is foolish since there is no ship design reason not to provide armor - the point of the post!
I think he was trying to point out that for the same weight, modern ships have a lot more volume, because many modern systems are less dense (compare a gun and its ammo vs missiles, launcher and guidance). So a modern ship might need twice (or more) as much square footage of armor to cover all its systems, which means twice the weight for the same level of protection.
DeleteRandall Rapp
I've deleted anon's comments (opted to leave the main comment so as not to delete other people's comments) as being incomprehensible.
DeleteRandall, today's ships, a Burke for instance, have all the electronics, HVAC, and whatever that they need. The point is that the same size ship from WWII was able to have significant armor without sacrificing performance. We could, and should, do the same, today. We could, and should, build a Burke with the armor of a WWII cruiser. It's just a simple naval architecture exercise which we knew how to do in 1940.
Delete"many modern systems are less dense"
DeleteThat statement may be intermittently true but is hardly universally true. For example, have you seen pictures of the fire control computers of the time? They were monstrous beasts with mechanical workings. Today's fire control is a PC for all intents and purposes. The electrical systems (fuse boxes, vacuum tubes, cabling, etc.) were massive compared to today's electronics (micro-circuits, fiber optic cabling, computer chips, etc.). Today's electronics are infinitely smaller than in 1940. Today's engines (the ubiquitous LM series turbines) are a fraction of the size of WWII boilers and steam plants. And so on.
As I think about it, I'm inclined to say that your statement is mostly incorrect and so, too, is anon, if that was his point.
Can you think of anything that is actually bigger today than in 1940? There may be something but I'm not coming up with it, offhand.
I'm 100% on board... but....
ReplyDeleteWeren't Fletcher's built with STS which was roughly like HY100? Do we have enough mulls to make HY 100 economically?
Also, do we even have any mills that could make face hardened belt armor?
As I said, I'm on board, but I fear at least initially it wouldn't be cheap due to industrial atrophy.
Perforated armor is also a possibility. Reduced mass for better protection. Naval application would need a thin overlay to insure water tight construction. Super Bainite cannot be welded into the structure but that doesn't mean that it cannot be bonded or riveted to the bulkheads. Perforated armor could also be made out of HY100.
Deletehttp://www.army-technology.com/features/featuresuper-bainite-steel-perfection-in-impenetrability-4346392/
"Weren't Fletcher's built with STS"
DeleteYes and no. A lot of the hull was actually HTS, American HTS of the time though was stronger than the modern equivalent and would pass as armor steel today.
"which was roughly like HY100?"
Correct.
"Do we have enough mulls to make HY 100 economically?"
No, it's been a long time since I had access to the numbers, but from memory the US eats up about 87% of our HY-100 production on our Submarines, and that is actually our bottleneck on Submarine production.
Fortunately, we don't need to use HY-100, we can use the much more available HY-80 without significant loss in protective quality. The newly applied armor steel to the Iowa-class Battleships in the 1980s reactivations were HY-80 steel.
And, the real bell ringer here is simple - HY-80 steel is only marginally more expensive than typical ABS Shipbuilding Steel.
Assuming the bracing was there for it (it isn't), we could build an entire Burke out of HY-80 for only an increase of maybe 50 million dollars per hull (not sure on this figure, it was a quick guesstimate) - and there is no reason to go that far on a light ship like a Burke.
Scaling up the HY-80 production would only be as complicated as scaling up any other wartime industry requirement. A couple billion dollars of upfront costs. We have the steel workers sitting around doing nothing that would be willing to work again.
Of course, if you go in the nearly completely opposite direction, and declare cost not an object, then the US could employ Dahlgren's 'Carbon Nanoplate', which they claim is between 26 and 62 times the effectiveness of steel in any given thickness (depending on quality of materials and thickness, as the material's effective thickness scales non-linearly) while only being 18% as heavy as steel.
Unfortunately, this type of hypothetical is only possible in the realm of the hypothetical, the primary reason why Carbon Nano-Plate isn't being jumped on by the USN is that the material alone (not counting processing) costs over 1670 times more than steel by volume (about $2197.66/in^3, just for the materials).
Bringing down the cost is entirely possible by actually having more than one plant that could make this material, and acquiring sources of the raw material asset, but this will still cost billions and only allow for limited rate (but usable) production - similar in effect to the Class A plating of WW2, except a lot more expensive.
- Ray D.
Ray, nice informative write up. Thanks.
DeleteAre you the Ray from the forum, famous for his knowledge of Fletchers?
Correct me if I'm wrong about this but my understanding is that the HY-100 has 20-25% higher yield strength compared to HY-80 so there is a numerically significant difference. Whether that translates to a significantly better "armor" effect, I don't know. Presumably, it does.
Also, once upon a time, we were moving from HY to HSLA for its easier weldability. Whether that trend continued, I don't know. I know significant chunks of the Burkes were designated for HSLA early on but I don't know if that's continued throughout the construction cycles.
Good comment! Thanks for contributing.
"Are you the Ray from the forum, famous for his knowledge of Fletchers?"
DeleteNegative, I am not, sorry to disappoint.
"Correct me if I'm wrong about this but my understanding is that the HY-100 has 20-25% higher yield strength compared to HY-80, so there is a numerically significant difference."
Correct.
The HY series of USN metal standards actually derives their names from their respective Yield Strengths.
HY-80 steel is High Yield 80 ksi (thousand lbs/in^2) Steel, whereas HY-100 steel is High Yield 100 ksi Steel, meaning HY-100 has a 25% higher yield strength.
This is actually slightly misleading when it comes to a material's protective value.
Yield Strength is the capability of a material to withstand compressive force and return to its original form, for example the strength of a wall to hold up a roof. Essentially it's structural strength.
When considering for armor steel, however, the values you have to pay attention to are Ultimate Tensile Strength and Hardness.
This leads me to...
"Whether that translates to a significantly better "armor" effect, I don't know. Presumably, it does.
Ultimate Tensile Strength (UTS) is, simply put, the amount of force a given metal can resist before it is torn apart, ether by a vice or a projectile slamming into it.
Hardness is, for most purposes, an obvious effect and I won't spent the character limit breaking it down.
For HY-80/100, these values are a lot closer than their Yield Strengths.
HY-80 has a Rockwell Hardness of 20 and a UTS of 100ksi.
HY-100 has a Rockwell Hardness of 21 and a UTS of 115ksi.
A roughly 13% difference.
So, yes, HY-100 can easily be a significantly better armor material than HY-80, and the nearly Titanium-like HY-130 doing even better... when employed in significant enough thicknesses for that to make a difference.
When you are dealing with thinner sheets, such as hull plating, it is generally more economical to design the ship around using a slightly thicker sheet of HY-80 than HY-100 unless the yield strength of the metal is going to come into play, such as with Submarines - and even then, we used to build Submarines out of HY-80. You end up with a slightly heavier ship, a few tons, but it presents a much more economical building plan.
"I know significant chunks of the Burkes were designated for HSLA early on but I don't know if that's continued throughout the construction cycles."
I actually am not sure either; however, it is worth pointing out that HSLA is comparatively much worse as an armor material than the entire HY-series, possessing a relatively low hardness, lower UTS, and inability to be produced in thickness - in addition to costing more than HY-80 to begin with. Practically the only advantage of HSLA is its weldability.
- Ray D.
Ray, another excellent, informative comment. Do you happen to know the armor/plating layout of the proposed Burke Flt III's or the general armor/plating type/thickness of the LCS? If so, it could make for a good guest post, if you have any interest.
DeleteAlso, are you aware of any public domain studies of explosive effects/resistance on the various steel types?
"Perforated armor is also a possibility."
DeleteMichael, good thought. Have you seen any applications of perforated armor on ships? One of the stated mechanisms of performance for perforated steel is that the edges of the perforations break up the incoming bullet/shell. These are meant for land use and relatively small rounds. Care to speculate how perforated armor would perform against large head torpedoes or larger naval shells where the heads are many times larger than the perforations?
I have not seen any applications of perforated armor on ships as of yet. The technology as you say has been proposed for land warfare and is a somewhat new invention. Given the lack of interest in armor in general in the Navy I don't see any application of perforated armor in the near future. We will have to lose 20 destroyers before the Navy values passive survivability to any great extent.
DeleteThe armor thickness and the perforations are sized to the expected threat level. Armor to withstand 5 inch shells could have larger perforations (1-2 inch diameter holes or slots) and be equally thick or thicker (3-6 inches). Perforated armor's reduced mass allows for thicker armor to be installed for a given mass. The perforations if designed well do not have to reduce strength and if faced, similar to honeycomb composites, could show increased stiffness and strength.
Torpedoes are tough to defeat. Multiple bottoms and side blisters were some of the common methods to improve survivability. Think egg crate stacked on egg crate stacked on egg crate. Massive crumple zone along the bottom and side of the ship to absorb energy and prevent a keel break or perforation.
Energy dissipation is key.
I have thought a little about filling the voids in the perforated armor with foamed metal inserts. Foamed metal has incredible energy absorption capabilities and could prove beneficial.
I have also thought about v shaped internal bulk heads as a torpedo defense. Most of the new land vehicles use a v shape to direct energy away from the crew. Anything outside of the central v is sacrificial energy absorption. A ship design with Mission critical inside the v and sacrificial outside. You might have to sleep in a corridor if your berth is sacrificed to save the ship, but at least you have your ship and are able to continue fighting.
Michael, good thoughts. I, too, have wondered about v-shaped armor on the bottom of the hull although I've focused on exterior v-shaped plating with void/crumple zones behind as opposed to the interior v. That's a good thought on your part.
DeleteI think there are many potential armor improvements that can be investigated but, as you say, the Navy seems to have no interest whatsoever - much like large caliber naval gun support!
Maybe you'd like to draw up a cross sectional sketch to illustrate your armor arrangement and present it as a guest post?
I'm not sure a V-shaped keel would be an effective defense against a torpedo attack. An explosion underneath the ship lifts a ship upward and as the bubbles collapse, the ship falls back into the water which can break the hull of a ship.
DeleteAbout 5 years ago, an Australian submarine, HMAS Farncomb, sank the former USS Kilauea (T-AE-26) with a single Mk 48 which exploded under the ship's bridge. The linked article has some interesting pictures.
http://www.dailymail.co.uk/news/article-2178197/Dramatic-moment-U-S-Navy-ship-sunk-torpedo-Australian-submarine-target-practice.html
"I'm not sure a V-shaped keel would be an effective defense against a torpedo"
DeleteI'm not sure it would be either. The point was that it would be well worth looking at.
The very slight evidence we have suggests that it could be effective. It works on land for mines that explode under a vehicle and a ship is just a vehicle that drives on a slightly less dense "ground". The explosive effect that is propagated on land/air is the same explosion that propagates in the water - just the water is denser than air.
It's almost certain that a v-hull would mitigate the effects of an under-hull explosion. The question is whether the mitigation would be sufficient to justify the use.
Do you have some evidence to suggest that it won't work?
An explosion on land propogates much farther than under water because water is about 1,000 times more dense than air.
DeleteAn explosion under the hull of a ship creates a bubble that first lifts a ship upward and as the bubble collapses, the falls back into the water. But, as the ship falls back into the water it is still supported at either end, this puts a load on the ship which can cause the hull to break.
On land, a V-shaped hull directs the force of an explosion sideways because the ground underneath isn't displaced. A V-shaped hull will not, in my opinion, affect how water is displaced under the ship from an underwater explosion.
"A V-shaped hull will not, in my opinion, affect how water is displaced under the ship from an underwater explosion."
DeleteOf course it will. Water is just a fluid like air but with some different property values like density. The only question is whether the V-hull can sufficiently mitigate the effects. Unfortunately, neither of us knows. Arguing about something neither of us has sufficient knowledge about is foolish and pointless. Unless you have some actual data to present, that's enough of this discussion.
The biggest difference in how water and air transmit blast is that water is basically incompressible. This is why after a certain speed, hitting water is like hitting land. If you're moving faster than the water can flow out of the way, its like you hit a solid. So hull shape can change blast effects because it effects how easily water can flow past but unfortunately the blasts can come from almost any direction underwater, which means blast from the side will do different damage than if front or the rear. So a V shape might help with explosions but only from certain directions.
DeleteRandall Rapp
"So a V shape might help with explosions but only from certain directions."
DeleteYes, just as underbody armor for a land vehicle is only effective in mitigating underbody explosions!
Most modern torpedoes are designed to explode under the ship, hence the suggestion for a v-shape hull bottom.
"Also, are you aware of any public domain studies of explosive effects/resistance on the various steel types?"
DeleteNot off the top of my head, no.
I forget the exact math on it, it was never my thing, but the gist of it is simple.
Explosive deformation of metals is a contest of the Material's Yield Strength, Ultimate Tensile Strength, Melting Point, and Mass/Area verses the Violence, Density, Mass, proximity (and resistance of the substance between the Material and the Explosion), and relative shape of the Explosion.
If you were wanting the material to just completely shrug off the explosive, you are mostly looking at Yield Strength.
Technically speaking, you can actually no-sell almost any torpedo with a large enough hull, which negates the 'backbreaking' effect of Under-Keel detonations, and thick enough hull plating, which causes the Yield Strength of the Material to simply overpower the Violent Velocity of the Explosive, and correct placement of the propulsion as well as armored rudders.
Take an 800' long (waterline) hull with 1" thick HY-130 steel hull plating and heavy duty bracing (think Battlecruiser) and internal (deep hull ducted propellers) propulsion, the ship would be nearly immune to most non-nuclear torpedoes, barring a repeated beating in the same location.
The problem is, doing this is not only an economic nightmare (guesstimate: a quarter of a billion on materials alone), it would be a structural one too (guesstimate: 22,200 tons, just in the hull plating), which is why nobody does it. It's not that we don't know how, it's that it's completely impractical.
Certainly, we could use alternative materials, such as Titanium, or construction practices, such as a carbon nanotube honeycomb composite, but both of these drive up the cost of the ship.
Although, I must admit, from where I am sitting, 12500 tons and $250 million dollars extra does not sound like a bad deal for a highly torpedo/mine-resistant Cruiser. All in all, the ship may cost an extra Billion Dollars... meaning, assuming the Cruiser was to be like the Ticos compared to the Burkes (just as a baseline example), we could have had these super-cruisers for the cost of the Zumwalts. Quite honestly, I would have rather had a Torpedo/Mine-resistant Ticonderoga (with plenty of command space!) than any of the Zumwalts.
"Most modern torpedoes are designed to explode under the ship, hence the suggestion for a v-shape hull bottom."
With all respect, CNO, this isn't entirely correct.
There are three types of major torpedo - Contact, Under-keel, and Wake.
The US and allies use a mix of Under-keel and Contact.
Russia and China primarily uses Wake and Contact.
Neither of them particularly are enchanted by Under-keel, because they both know the effect is impractical to use against large surface ships, and they focus on taking out the US' Carriers, which are all large ships - in fact, NavWeaps isn't aware of Russia having any Under-Keel torpedoes at all except a late WW2-type one in 1951, and basically all of our potential enemies use Russian-derived Torpedoes.
And, a v-shape bottom really wouldn't do anything good of note, the water pressure would still direct most of the force directly into the hull of the ship.
Remember, force will always try to find the easiest path, and underneath a ship at sea that path is always through the ship - the water around the ship weighs a lot more than that ship, presenting much more resistance; and, unlike air, water simply does not want to move.
In fact, the v-shape bottom would only make an under-keel detonation much more severe to the ship as the explosion would find less resistance along the v.
Better to just slam it against a wall of metal rather than let it envelop what it is trying to destroy.
Just my opinion, of course.
- Ray D.
"Russia and China primarily uses Wake and Contact."
DeleteI'm prepared to stand corrected on this but not yet. My understanding is that Russian wake homing torps explode under the ship. Wake homing is the guidance system but does not necessarily dictate a stern surface contact detonation. A quick recheck of NavWeaps gives no indication that the various Russian torps are or are not under-ship exploders. Feel free to correct me with a reference.
"Remember, force will always try to find the easiest path, and underneath a ship at sea that path is always through the ship"
DeleteI've got a post coming about underwater explosion mechanisms that will disabuse all of us of our previous notions about torpedo lethality. The post is a review of scientific papers rather than an opinion piece. I think you'll find it interesting. I learned much from it. I hope to have it ready in the next few days.
"My understanding is that Russian wake homing torps explode under the ship"
DeleteThat is correct, Under-Keel torpedoes do not have sole ownership of exploding underneath a ship - all three types can do that.
I supposed I should explain the terminology that I am familiar with.
'Under-Keel' type torpedoes attempt to break the keel of a ship, they aim for just underneath the immediate center of mass where the resulting concave of the pressure bubble will cause the most damage to a ship's keel by way of using the ship's own weight against it. If they miss, they can still be used as Contact Torpedoes.
'Wake' type torpedoes are Wake Homing torpedoes that primarily attempt to destroy the propellers, propulsion, and rudders of a ship - generally the 'single' weakest points of any given ship, as even a cursory read over naval history proves.
It was Soviet naval doctrine that an Immobile ship was a dead ship, and I have no reason to believe that they have changed their opinions. Even though they are detonating underneath the ship, they are not detonating under the exact center of the ship's mass, cannot take advantage of a ship's weight, and as a result do an entirely different sort of damage to the ship's hull. If they miss, they can still be used as Contact Torpedoes.
'Contact' type torpedoes ironically rarely are actually built to make contact with the ship anymore, most of them are proximity fused - the name is purely legacy. They are indiscriminate about where they 'hit' the ship/target, merely trying to ram through the ship's torpedo defense system (TDS) and cause general purpose flooding, chaos, and havoc. They are still today the most prolific type of Torpedo in the world, and almost all Anti-Submarine Torpedoes are contact torpedoes.
I don't have an immediate reference at hand, though, most of this mostly from memory. So you can consider this opinion, if you like.
I'm mostly just explaining where I was coming from with what I said.
- Ray D.
It's interesting about ship construction and a vey valuable information from this blog as to the Burkes being combat proven you are the last combat proven ship to ship combat we most likely would have to look to WWII as I can't remember any other significant naval engagement since the unless we count the Israeli sinking of the Egyptian destroyer
ReplyDeleteOFFTOPIC check this Korean Supercavitating Torpedo Test
ReplyDeletehttps://www.youtube.com/watch?v=PwD1nAfQsy0
Correction the Egypt actually sank the Israeli destroyer Eliat with the Styx missiles as I now recall un the six day war did not mean to mislead
ReplyDeleteOf course there is a performance penalty to be paid for pursuing heavier construction standards (let alone armour). Increased displacement will increase resistance and require more power to accelerate to and sustain a given speed, thereby increasing fuel burn (and therefore operational cost) and reducing endurance. The trade-off could well be worth it, but it is foolish to pretend that it doesn't exist.
ReplyDeleteComparisons with ships of from a half-century or more ago are useless. That a Fletcher-class destroyer can make X speed and Y range says nothing about what it could've done with no armour and lighter construction standards, or what it could do (besides capsize) if you had to stuff the guts of a modern warship into it as well.
You've completely missed the point of the post. I'll summarize it for you. The premise among many is that modern ships CAN'T bear the weight of armor and, if they could, WOULD SUFFER ENORMOUS PENALTIES IN PERFORMANCE. That's absurd. A properly designed ship (hence, the WWII examples) can have significant armor and good performance.
DeleteNo one is claiming that a ship can have infinite weight and size and be powered by nothing more than good wishes. The point is, to repeat, that a properly designed ship CAN have armor and performance as proven by all the WWII surface ships.
One question--how tough and armored are our potential opponents?
ReplyDeleteI know the Russian reputation is of crude but heavily built weapons, does this go to ships as well? I know their subs tend to be double hulled for example.
Are Iran, China, Russia, North Korea, or whoever else we may cross swords with building ships with the fortitude of a WW2 vessel?
Or is this one more thing the USA is falling behind on?
That's a great question for which I have no answer.
DeleteLets explore the potential opponents. China just launched their new 10,000 ton destroyer, the Type 055.
DeleteThe first Type 055 destroyer began construction in 2015 and is expected to have a full displacement of over 14,000 tons according to reports. This leaves plenty of room for even minor armor.
I'm only speculating here but it seems like this ship is built for blue water surface combat in mind.
It's just not torpedoes that are a threat. A good size mine 30 to 40 meters away and could damage a ship's hull as well.
ReplyDeleteWe have seen the aggressiveness of China's "fishing" militia and the size of their CG cutters. It is not unreasonable to think they might ram a naval vessel or two as an "accident" in the lead up to a conflict. A Burke acting as eyes for the fleet would make tempting target now they know the damage it could sustain. We might not think of doing such a tactic but many nations would.
ReplyDeleteYou realize that modern cruise missiles with shaped charged warheads can penetrate up to 12 inches of face-hardened WW2-era armor? The USN did a study on ASCM's verses ship armor in 1991 as the BB's were operating in the Persian Gulf for Desert Storm. It concluded that modern, large Soviet ASCM's could penetrate BB belt armor. Ship designers have also eschewed armor since 1945 because (1) it does nothing against nuclear effects and (2), the design of ships needed to change to support lots of weight above the main deck in the form of radars and communications gear.
ReplyDeletePlease don't fall into the group of thought that believes armor has no value just because there is some weapon, somewhere that can penetrate it. I've done a post of this and I invite you to check it out. (see, Armor for Dummies)
DeleteUsing your logic, one would remove kevlar vests from soldiers just because they can't stop a 0.50 cal round or a tank shell. What armor, whether individual or ship, does, is provide protection from near misses, shrapnel, and off-angle hits. That kevlar vest that won't stop a 0.50 cal that hits straight on, may be sufficient to deflect a 0.50 cal that hits at an angle. Similarly, ship armor that may not stop a straight on, shaped charge missile may well deflect it if it strikes at an angle.
The referenced post also discusses the kinetic energy dissipation as weapons strike. Even if a missile can't be totally stopped, it's kinetic energy will be much more dissipated trying to pass through armor and it will not penetrate as deeply into the ship as it would if there were no armor.
"Armor is useless because it won't stop every weapon" is a badly flawed concept. The purpose of armor is not to completely stop every conceivable weapon (though it will stop some!) but to MITIGATE damage from a hit. It's not even debatable that armor will mitigate the damage and significantly so.
If you truly believe that there is absolutely no point to armor because it can't stop every weapon then you should, logically, also believe that ships should be built with the thinnest sheet metal possible that just barely keeps out seawater. Those Burkes with up to 0.50 inch steel plate should be built with 1/16 inch sheet metal because 0.50 inch plate won't stop any serious anti-ship weapon. I suspect that you don't really believe that and that your gut understands why some armor is better than no armor.
Wow. Argument by strawman, or just miscommunication?
ReplyDeleteI don't believe we should remove soldier's vests because they cannot stop a tank round. That would be dumb.
I'm saying that for most of the battleship era, pretty much every designer went with all-or-nothing armor. https://en.wikipedia.org/wiki/All_or_nothing_(armor)
Why are you rejecting the all-or-nothing concept, which pretty much every designer imbrased to some extent for most of the period when ships had armor
Who are you, who are you addressing, and who rejected all-or-nothing armor?
DeleteI'm having a hard time understanding how anything less than Iowa class battleship armor is going to keep out a modern missile. And even that seems likely to fail.
ReplyDeleteAn Iowa had a narrow belt of armor at the waterline that was very strong. But even an Iowa had a deck armor that could be penetrated by a modern missile, and that deck did nothing to protect the superstructure that contains all the expensive parts of a modern warship (except the engines).
Could you describe the armor you have in mind, and explain why you think it will keep out a modern missile?
Read "Armor For Dummies"
Delete"even an Iowa had a deck armor that could be penetrated by a modern missile"
DeleteAre you making that up? Give me a reference that proves that.
First, from Page 141, "Battleships", William Garzke
Delete"At Pearl Harbor the Japanese dropped what were believed to be 14" armor-piercing shells modified for use as bombs. The Germans were reported to have used heavy caliber projectiles in the same manner. The nearly vertical impact of such projectiles gave them much greater penetrative power against deck armor as compared to the more oblique impact of shells fired at long range. Design and construction of the Iowa class ships were too far advanced to compensate for this new threat, which soon made it practically impossible to provide horizontal protection against armor-piercing bombs"
Second, from https://en.wikipedia.org/wiki/Kh-22
"Soviet tests revealed that when a shaped charge warhead weighing 1,000 kg (2,200 lb) was used in the missile, the resulting hole measured 5 m (16 ft) in diameter, and was 12 m (40 ft) deep.[3][4] Soviet Tests showed that a Kh-22MA equipped with 1,000 kg (2,205 lb) RDX warhead and with an approach speed of 800 m/s (Mach 2.4), used against an aircraft carrier, will make a 22 m2 (240 sq ft) diameter hole, and the warhead's cumulative jet will burn through internal ship compartments up to a depth of 12 m"
I'm assuming a 1000lb shaped charge using modern explosives has more penetrating power than a 70 year old 14" Japanese shell.
Anti-ship missiles do not impact from near vertical so your description of 14" shells is not valid. While some cruise missiles do a pop up and steep dive ontot the target, the dive is nowhere near the vertical drop of an unguided, free-falling bomb. Further, large, armor piercing shells are constructed completely differently from missiles which have just a very light construction. AP shells are heavy and designed to, well, penetrate armor. Standard cruise missiles break up upon impact and are not designed to penetrate. A shaped charge missile might penetrate but the degree of penetration versus serious armor has never been tested, as far as I know. The only tests I'm aware of involved old US Navy cruise missiles against battleship plate and the result was absolutely no penetration.
DeleteThe Soviet test appears to have involved standard ship plating rather than armor. The test proved nothing about impact against armor.
I conclude that you have no basis to claim that a missile could penetrate the deck of an Iowa. It might, but you have no evidence of it. Please don't make unsupported claims.
As an aside, there is no relationship between age and explosive/penetrating power. I would take a 16" AP shell over a missile!
By the way, did you read the linked armor post? If so, you understand the benefits of armor and this discussion is not fruitful.
Just to be clear ...
DeleteYour claim is that a 14" shell using explosives from the 1940s free falling has more penetrative power than a 1000 lb shaped charge using modern materials and design, moving over Mach 2?
All depends on what a modern missile can actually do. There is no public domain data on missiles (shaped charge or otherwise) versus heavy naval armor so it's all pure speculation.
DeleteThat said, I'd generally take a 2500 lb 16" AP shell travelling at 2500 fps (Mach 2.2) over most missiles, absent any definitive data.
So going back to the original question ... could you describe the armor you envision? Are we talking battleship amounts of armor, or more like a WWII cruiser. And do you want to armor the whole deck, or just engines and VLS cells?
ReplyDeleteThis isn't that difficult. You seem to be trying to make an argument about something that's straightforward. I advocate battleship armor for battleship size ships, cruiser armor for cruiser size ships, and so on. There's not really any mystery.
DeleteI also want the Navy to conduct armor/protection research and develop new armor and protection schemes just as has been done for tanks and land vehicles.
This is just common sense. If we can add a degree of additional armor/protection to a ship, why wouldn't we? That some degree of armor won't totally stop the most powerful weapon in the world is not a reason not to have armor. It's just theoretically possible that a ship might be attacked by a weapon that is less powerful than the most powerful weapon in the world. At that point, any armor would be welcome and useful. You've read the linked post about armor so you now understand the benefits of armor even in cases where it doesn't totally stop a given weapon.
There's not really much to discuss. Many of the things I talk about on this blog are debatable. Armor for ships isn't really one of those.
"There's not really much to discuss. Many of the things I talk about on this blog are debatable. Armor for ships isn't really one of those."
DeleteApproximately no navy in the world does this thing, you think they should do this thing, and your conclusion is so obvious that it's not really debatable.
My question is: why do you think approximately no navy in the world does this very obviously right thing?
I've laid out my reasoning. You can accept it or not. I'm done with this.
Delete