Maximum possible ship size

[PersonMan]

What I want to know is how large/heavy a ship can be before it sinks. Effectively, I want to know exactly how absurdly large I can make a ship, and how absurdly powerful I can make its main cannons.

Also, how large of a crew would such a ship need, and how would the nations of the world react if such a ship was found in the open ocean? Also, would it be better to use railguns or conventional cannons on such a ship?

Yes, this is(sort of) related to my Manning a Dreadnought thread.

[Thajocoth]

Infinity. It just needs to displace it's volume of water without sinking. No matter how big or heavy, if it's hollow enough, it'll accomplish this.

Buoyancy. It's what floats your boat.

[Maximum Zersk]

Infinity. It just needs to displace it's volume of water without sinking. No matter how big or heavy, if it's hollow enough, it'll accomplish this.

Buoyancy. It's what floats your boat.

Ah, but what about Square Cube Law?

[PersonMan]

Infinity. It just needs to displace it's volume of water without sinking. No matter how big or heavy, if it's hollow enough, it'll accomplish this.

Buoyancy. It's what floats your boat.

Nice.

So, how about a ship, say, four times the size of an Iowa-class ship? What sort of armament would be best suited for it, and how would the world react to its appearance?

[Erloas]

Well the largest ships around right now are cargo ships. I have no idea how big they are, but they are very big. Do a search on them.

And really there isn't a maximum size that will float, the limitations generally comes in actually moving the ship or getting the ship close enough to land to be able to dock at a port.

Wikipedia shows the largest cargo ship as
2009 MSC Danit 365.50 m long, with a gross total weight of 153,092 tons.


The biggest ships by gross tonnage ever constructed were four Batillus-class supertankers built in France at the end of the 1970s, having 555,000 metric tons deadweight (DWT) and a 414-meter length

Economies of scale have dictated an upward trend in sizes of container ships in order to reduce costs. One limit on ship size is the "Suezmax" standard, or the largest theoretical ship capable of passing through the Suez Canal, which measures 14,000 TEU. Such a vessel would displace 137,000 metric tons deadweight (DWT), be 400 meters long, more than 50 meters wide, have a draft of nearly 15 metres, and use more than 85 MW (113,987 hp) to achieve 25.5 knots, specifications met by the Emma Mærsk.

Beyond Suezmax lies the "Malaccamax" (for Straits of Malacca) ship of 18,000 TEU, displacing 300,000 DWT, 470 meters long, 60 meters wide, 16 meters of draft, and using more than 100 MW (134,102 hp) for 25.5 knots. This is most likely the limit before a major restructuring of world container trade routes.[10] The biggest constraint of this design, the absence of a capable single engine, has been overcome by the MAN B&W K108ME-C.

The ultimate problem was the absence of a manufacturer capable of producing the propeller needed for transmitting this power, which would be about 10 metres in diameter, and weigh 130 tonnes. One has since been built for the Emma Mærsk by Mecklenburger Metallguss GmbH in Waren, Germany. Other constraints, such as time in port and flexibility of service routes are similar to the constraints that eventually limited the growth in size of supertankers.

[UglyPanda]

You need to give some more information here. And a lot of qualifiers.

Things that would need to be answered first:What do you define as sinking?
If you define it as merely having a deck that's above the surface of the water, then you can have a ship of any height since it could simply sit on the bottom of the ocean floor.

Does it have to be structurally sound?
By the way, if it does, then that makes the question more complicated and along the lines of something the XKCD forums would figure out.

Does it have to be made from real-world materials?
See previous question.

What do you define as a boat?
You could have it as wide as you want if you give the boat no height. In other words, your boat could just be a lot of planks and raft pieces tied together.
I think most nations would not care about a theoretical super-boat. Long-range missiles and high-speed bombers are the name of the game.

[PersonMan]

The ship doesn't need to worry about getting close to land, just propulsion.

EDIT: I see. Well, then, I think I'll ask them as well.

[Mando Knight]

What I want to know is how large/heavy a ship can be before it sinks. Effectively, I want to know exactly how absurdly large I can make a ship, and how absurdly powerful I can make its main cannons.

Also, how large of a crew would such a ship need, and how would the nations of the world react if such a ship was found in the open ocean?

Yes, this is(sort of) related to my Manning a Dreadnought thread.

How absurdly heavy it can be is in direct proportion to how absurdly large it is. Largest ships sailing the seas now are supertankers, which can weigh upwards of 550000 metric tons of deadweight and can be nearly half a kilometer long.

For fitting in the Panama Canal, a ship must be just under 290 meters long and have a maximum deadweight of around 80000 tons.
The ship doesn't need to worry about getting close to land, just propulsion.
Propulsion isn't the issue here: a super-massive naval vessel would theoretically be outfitted with a nuclear power system like Nimitz-class aircraft carriers. The big issue is presenting too large of a target: Being the size of a supertanker is strategically stupid when fighting countries that will then decide to fight it with strategic weapons instead of tactical ones. You want it to be small enough that launching a nuke would be a touch too unreliable and big enough to dominate its competition in ordnance. That's why we use aircraft carriers now instead of super-dreadnoughts.

[Maximum Zersk]

Again, Square/Cube Law, and all that. The larger you get, the stronger materials you need. See, while the mass of an object goes up by the cube of it's size (2x2x2=8), the factors that strengthen it and it's surface area do not. Thus, weaker object.

[poisonoustea]

This is the Knock Nevis (http://en.wikipedia.org/wiki/Knock_Nevis), the world's heaviest and largest ship.

Since ships use the laws of physics to stay on top of the water, as long as you keep 'em proportioned and well-built you can make 'em as big as you want. You can easily make a believable moving city if that's your intention. There are limitations of course: such a ship will have a hard time moving into waters that are not ocean-deep, and its bulk will probably be against logic (why not a fleet of ships instead of a big one?). You'll have to find good reasons for that.

Also see icebergs (http://en.wikipedia.org/wiki/Iceberg_B-15), they work the same way as ships (floating).

[PersonMan]

Again, Square/Cube Law, and all that. The larger you get, the stronger materials you need. See, while the mass of an object goes up by the cube of it's size (2x2x2=8), the factors that strengthen it and it's surface area do not. Thus, weaker object.

I see. So, to make a sufficiently absurdly huge ship that can take a hit, I need absurdly strong materials? Or are normally strong ones good enough?

[Maximum Zersk]

I see. So, to make a sufficiently absurdly huge ship that can take a hit, I need absurdly strong materials? Or are normally strong ones good enough?

Depends on what you mean by "Absurdly Huge."

[PersonMan]

Depends on what you mean by "Absurdly Huge."

Hmm. Probably as large as the aformentioned Knock Nevis, but it needs to be able to have enough armor to be able to be in naval combat and survive.

[Maximum Zersk]

Hmm... possibly actual Real-Life materials. Would just have to be light, but strong.

To be honest, I thought you meant bigger. Never mind. :smalltongue:

[poisonoustea]

Hmm. Probably as large as the aformentioned Knock Nevis, but it needs to be able to have enough armor to be able to be in naval combat and survive.
You mean modern warfare? I don't think it can stand a chance against modern weaponry. Most of these incredibly large ships are cargo ships or carriers; they won't engage battle directly as they're relatively weak targets. A single heavy missile under the hull can sink it pretty badly... and I don't know if submarines can launch nukes. They probably can.

If you want to keep it realistic (e.g. your setting is a real-world, no-magic, no-alien-tech setting) , make an oversized fleet instead.

[snoopy13a]

Even in a conventional naval battle, a dreadnought would be taken apart by fighter planes from an aircraft carrier launching anti-ship missles. Battleships have not ruled the seas since WWII.

[PersonMan]

Hmm... possibly actual Real-Life materials. Would just have to be light, but strong.

To be honest, I thought you meant bigger. Never mind. :smalltongue:

Meh. It's sort of large enough for what I want. The original thing I had imagined was large enough to make the largest modern warships look very small in comparison, had guns heavier than entire ships, and could destroy dozens of smaller ships with a single broadside. I'm thinking it'd be...*looks up reference pictures* about as long as the Empire State Building is tall, maybe around 1500 feet.


Even in a conventional naval battle, a dreadnought would be taken apart by fighter planes from an aircraft carrier launching anti-ship missles. Battleships have not ruled the seas since WWII.

Ahhh, you assume a lack of an absurdly complete anti-air defense system?

The next part of the question: What kind of defenses would such a ship need to make air attacks as little of a threat as possible? I'm looking for AA capability, although making it a huge submarine would probably help as well...

[Force]

A single heavy missile under the hull can sink it pretty badly... and I don't know if submarines can launch nukes. They probably can.


Ballistic and cruise missile subs can; I believe some attack subs are armed with nukes, but all subs have conventional missile capable of destroying ships as well as torpedoes.

A really big dreadnought in the modern age is going to have to be packed with extraordinarily large amounts of ECM and point defense systems to be worthwhile. The cost-benefit analysis, though, says that a ship armed primarily with guns is worthless in today's environment except for shore bombardment. Better to use missiles instead with smaller guns for backup and use smaller ships or subs to deliver those missiles.

[PersonMan]

Ballistic and cruise missile subs can; I believe some attack subs are armed with nukes, but all subs have conventional missile capable of destroying ships as well as torpedoes.

A really big dreadnought in the modern age is going to have to be packed with extraordinarily large amounts of ECM and point defense systems to be worthwhile. The cost-benefit analysis, though, says that a ship armed primarily with guns is worthless in today's environment except for shore bombardment. Better to use missiles instead with smaller guns for backup and use smaller ships or subs to deliver those missiles.

I see.

Speaking of missiles vs. cannons, would using railguns reduce some of the disadvantages of it using mostly cannons?

[Mando Knight]

and I don't know if submarines can launch nukes. They probably can.

They can, but US submarines haven't fielded nuclear warheads on their cruise missiles since before the Cold War ended. They could if a threat necessitated a nuclear counterattack...
I see.

Speaking of missiles vs. cannons, would using railguns reduce some of the disadvantages of it using mostly cannons?
Nope. Railguns can't counter the threat of even a conventional cruise missile assault by an attack submarine: you have to find the target to hit it, and you can't find it if it detects you, launches its payload, then submerges in about the same time it takes you to notice it on your long-range sensors.

[PersonMan]

Nope. Railguns can't counter the threat of even a conventional cruise missile assault by an attack submarine: you have to find the target to hit it, and you can't find it if it detects you, launches its payload, then submerges in about the same time it takes you to notice it on your long-range sensors.

I see.

So, what sort of anti-missile defenses are there at this point?

Also, I don't think there is, but is there any way to have a "stealthy" warship? Any way to make it more difficult to detect?

[Force]

The next part of the question: What kind of defenses would such a ship need to make air attacks as little of a threat as possible? I'm looking for AA capability, although making it a huge submarine would probably help as well...

Phalanx gun and missile systems, as well as Sea Sparrow missiles. Lots of them. Also, lots of ECM (electric counter measures). Your dreadnaught should be able to fire dozens of these missiles at a time if it's to engage a modern carrier battle group. Even then... a carrier can fly off as many as 90 fighters, each of which can carry as many as six missiles. That means that a dreadnaught has to be able to destroyer 450 missiles with 98% accuracy (assuming it can take nine hits and survive).


I see.

Speaking of missiles vs. cannons, would using railguns reduce some of the disadvantages of it using mostly cannons?

Not really. Railguns are really just more powerful guns, when it comes down to it. The range is longer, accuracy is better (the faster a projectile travels, the less time the target has to evade it), and it does more damage-- but a Tomahawk cruise missile has a range of twenty-five hundred kilometers. An air-launched Harpoon missile has a range of about a hundred kilometers and almost triple that if launched from a ship. Virtually no gun can oppose a missile except at knife-fighting ranges. Your dreadnaught can be hammered at maximum range by carrier aircraft groups. All they have to do is sit at the edge of their operating envelope and hammer the dreadnaught with repeated Harpoon and Tomahawk strikes until they run out of ammo or you do, and chances are you will die first. You can't catch them unless your dreadnaught can steam as fast as a Nimitz, and I very much doubt that.


I see.

So, what sort of anti-missile defenses are there at this point?

Also, I don't think there is, but is there any way to have a "stealthy" warship? Any way to make it more difficult to detect?

In the era of spy satellites, your ship is going to be detected within hours of its leaving port. You can minimize radar return with the proper design and use of materials that absorb radar waves, but that will cut deeply into your combat capability. Look at a US Airforce Blackbird-- it can't carry ordanance outside its internal bomb bays or its stealth is compromised. Your dreadnought cannot have anything project from its surface (i.e. guns, point defense stations, conning tower) if it is to remain stealthy.

In short, no stealth without destroying the combat capability of the dreadnaught. You could possibly jam radar systems by blaring radio waves to the point the enemy cannot pinpoint your location, but that will let the enemy know you're coming, and they'll know about where you are (within several square miles). They can also use HARMs, missiles that will lock onto the nearest source of radiation and follow it in.

[Erloas]

Your biggest concern is probably under water based attacks. Its not too hard to build AA, even some fast enough to shot down quick and small missiles. However, doing the same thing under water is exceptionally more difficult. Normally projectiles work very poorly under water, even things like railguns aren't going to work because its the resistance of water (compared to air) that makes things difficult. And of course energy weapons, assuming you could get them working, wouldn't work under water very well either. And with that much above water you have a lot more under water and things can come at you from any direction.

[horngeek]

Depends on how vocal the fans are. (http://tvtropes.org/pmwiki/pmwiki.php/Main/ShipSinking)

...oh, right. THAT kind of ship. :smalltongue:

[Pyrian]

Again, Square/Cube Law, and all that.They don't apply in the usual sense. The square-cube law is normally cited as a restriction on the structure of large animals to support themselves. Ships, like whales, do not have to support their own weight longitudinally (except from their own thrust, but that's usually small compared to other stressors), and generally speaking the larger ones cannot (thus the Titanic breaking in the middle when the front half started sinking).

The substructure does have to support itself against pressure, but that's relative to depth, not size/weight (except as they impact depth). A "floating island" could be arbitrarily large, unless of course you need propulsion...

One reason ships tend to be long rather than wide is that they need to move less water out of the way as they move, vastly improving their fuel efficiency. Multiple-hull (catamaran) designs can get around this problem to a certain extent, but don't scale up well unless you make the upper structure absurdly flexible (at which point you've really just got multiple ships roped together).

Just musin'.

[Mando Knight]

Look at a US Airforce Blackbird-- it can't carry ordanance outside its internal bomb bays or its stealth is compromised.

The SR-71 was unarmed, it was a spy plane. The B-2 stealth bomber and F-22 fighter jet, though, are both heavily armed stealth (or semi-stealth) craft that devote a large amount of design towards increasing the internal payload bays.

[PersonMan]

However, how long would it take to be found if it wasn't being searched for?

[Maximum Zersk]

They don't apply in the usual sense. The square-cube law is normally cited as a restriction on the structure of large animals to support themselves. Ships, like whales, do not have to support their own weight longitudinally (except from their own thrust, but that's usually small compared to other stressors), and generally speaking the larger ones cannot (thus the Titanic breaking in the middle when the front half started sinking).

The substructure does have to support itself against pressure, but that's relative to depth, not size/weight (except as they impact depth). A "floating island" could be arbitrarily large, unless of course you need propulsion...

One reason ships tend to be long rather than wide is that they need to move less water out of the way as they move, vastly improving their fuel efficiency. Multiple-hull (catamaran) designs can get around this problem to a certain extent, but don't scale up well unless you make the upper structure absurdly flexible (at which point you've really just got multiple ships roped together).

Just musin'.

Ah, okay. I assumed that since the whale spends a lot of it's time completely surrounded by water, that's by it didn't apply. But okay, that makes sense, I guess.

[Force]

However, how long would it take to be found if it wasn't being searched for?

I would assume that the US and other First-World countries use satellite intelligence to monitor the oceans. Probably twelve hours at most.

If satellite intel is off the table... it depends on where the dreadnought started from and where it's going. It'll probably be detected for a certainty not long after it enters US coastal waters. There's a good chance it would be intercepted by a submarine or aerial patrol long before that, though, and if they're unlucky a USN vessel pings them and steams over to see what's going on. It's also possible that a carrier group on patrol might detect the dreadnought in time to intercept it.

[PersonMan]

I see. At this point, I don't actually have a destination in mind-OH WAIT.

I do, now. So, assuming that it could get into coastal areas undetected, how do you think the US Navy/Coast Guard would respond?

[SurlySeraph]

In the era of spy satellites, your ship is going to be detected within hours of its leaving port. You can minimize radar return with the proper design and use of materials that absorb radar waves, but that will cut deeply into your combat capability. Look at a US Airforce Blackbird-- it can't carry ordanance outside its internal bomb bays or its stealth is compromised. Your dreadnought cannot have anything project from its surface (i.e. guns, point defense stations, conning tower) if it is to remain stealthy.

In short, no stealth without destroying the combat capability of the dreadnaught. You could possibly jam radar systems by blaring radio waves to the point the enemy cannot pinpoint your location, but that will let the enemy know you're coming, and they'll know about where you are (within several square miles). They can also use HARMs, missiles that will lock onto the nearest source of radiation and follow it in.

You could have a pretty stealthy warship with a design like a scaled-up Sea Shadow (http://en.wikipedia.org/wiki/Sea_Shadow_%28IX-529%29) with internal missile bays and torpedo tubes. It would give its position away briefly when launching, though shoot-and-scoot tactics could help compensate. However, that's not really going to work with the dreadnought full of guns that we're envisioning here.

Also, even if you have great point defense against missiles submarines will still be a huge problem. Why? Nuclear torpedoes. They were originally developed by the Soviets to one-shot carrier battle groups, and they'd be an extremely effective counter to a dreadnought like this. You could have an underwater point defense system using supercavitating bullets and/or torpedoes, but that would require a lot of technological advancements to be viable.

And while we're on supercavitation, a multiple-hull design (like SWATH (http://en.wikipedia.org/wiki/Small_waterplane_area_twin_hull)) plus lots of propulsive power could allow for a very fast ship. It would be quite silly and extremely difficult engineering to do that for a ship this size, but if you're going for awesomeness...

EDIT: I assume the Coast Guard response would involve wetting themselves, followed by desperately attempting to convince their superiors of what they were seeing and calling for the Air Force to get involved.

[Force]

I see. At this point, I don't actually have a destination in mind-OH WAIT.

I do, now. So, assuming that it could get into coastal areas undetected, how do you think the US Navy/Coast Guard would respond?

If it gets into coastal waters, is detected, and they know what they're dealing with?

Hail it, first, and order it to back off while calling in every sub in the area. If a carrier battle group is nearby, they get whistled up as well. If there is no response to the hail, or the response is negative ("No, we're not heaving to" is negative) then I'd expect a massive launch of land-based aircraft. Any subs in the area probably get clearance to hit the thing with Tomahawks; if there's a nearby attack sub it probably gets ordered to torpedo it. If that doesn't work the fighters hit it next, followed by any carrier battle groups. A F-18 Hornet has quite a long range if all it has to do is fly off its carrier, fire its missiles, and land on an airstrip, as opposed to returning to its carrier.

The Coast Guard stays out of this one. They don't have the firepower to be anything more than a speedbump.




Also, even if you have great point defense against missiles submarines will still be a huge problem. Why? Nuclear torpedoes. They were originally developed by the Soviets to one-shot carrier battle groups, and they'd be an extremely effective counter to a dreadnought like this. You could have an underwater point defense system using supercavitating bullets and/or torpedoes, but that would require a lot of technological advancements to be viable.

Agreed. Missiles, though, have a very long stand-off range; torpedoes do not (5-20 miles depending on the torpedo). If the dreadnought in question manages to get into coastal waters undetected chances are there isn't a sub close enough to torpedo it. Even if there was, I do not believe the USN has any nuclear torpedoes at the moment.

[PersonMan]

I see.

I have another question, how effective would a sort of flak-esque arrangement be for defeating missiles? Also, how much advancement would be required for an SDI system to be used/make sense on such a ship, if at all?

[Amiel]

You could have a ship of any size; as long as said size considers the financial sinkhole of plating the hull of the ship to be resistant to icebergs (the ninjas of the sea) and reefs. You don't want your trillion dollar investment to be fractured and then sink into obscurity, do you?

Railguns are possible, though they would need to displace the air around the tip of the gun; you wouldn't want the recoil to cause your ship to jump every time the gun is fired.

[Force]

I see.

I have another question, how effective would a sort of flak-esque arrangement be for defeating missiles? Also, how much advancement would be required for an SDI system to be used/make sense on such a ship, if at all?

Chaff, you mean, not flak? Flak isn't that useful against a missile. Doesn't move fast enough, for one thing.

SDI... Controlling anti-missile satellites from this dreadnought?:smallconfused: It's... possible, but nonsensical. If you mean using energy weapons as point-defense guns, possible but not probable. There is a system in development to do just that, but for land use. Lasers can be foiled by bad weather on land; at sea, they'd be worthless on all but the sunniest days.

[PersonMan]

Chaff, you mean, not flak? Flak isn't that useful against a missile. Doesn't move fast enough, for one thing.

SDI... Controlling anti-missile satellites from this dreadnought?:smallconfused: It's... possible, but nonsensical. If you mean using energy weapons as point-defense guns, possible but not probable. There is a system in development to do just that, but for land use. Lasers can be foiled by bad weather on land; at sea, they'd be worthless on all but the sunniest days.

Yes, I do. I'm not very familiar with these things, and am juggling reading/replying to three threads and emailing with a friend, so I might be a bit empty headed right now.

Yes, energy weapons.

[paddyfool]

Currently the largest floating thing on this planet is the ice sheet up at the North Pole. Even at the lowest extent yet seen (in September 2007), this covered an area of 1.6 million square miles. At its most recent maximum (March 2010) it covered 5.9 million square miles. Now, get a large enough crew, enough cannons, and somehow get all of that moving in the same direction, and there's your answer.

In a fantasy world, however? The sea's the limit ;-)

[Force]

Yes, I do. I'm not very familiar with these things, and am juggling reading/replying to three threads and emailing with a friend, so I might be a bit empty headed right now.

Yes, energy weapons.

Chaff is somewhat effective against missiles, to the point that several navies deploy it on their vessels. However, as your dreadnought will be very visible on radar, chaff will not be that effective. Helpful, certainly, but not an end-all.

Sure, energy weapons have advantages over guns (they're much faster, for one). At this point in time, though, there are no energy weapons currently in service as point-defense weapons. There was a project-- the THEL project-- that would have served as a decent point-defense weapon using lasers, but it was canceled.

Lasers, though, are vulnerable to fog, sea spray, and clouds; operation at sea, as I said earlier, will be problematic in all but the best weather. They'll work but I wouldn't rely on them to the exclusion of ballistic systems.

[PersonMan]

I see. So, what sort of anti-air systems could be used on such a ship, beyond AA guns and SAM launchers?

[SurlySeraph]

You could use relatively small-caliber rapid-fire railguns and coilguns, certainly, and SAMs work. It would be better if your ship had its own air wing so it could fend off threats from further away, though. I don't know enough to say for certain if any particle beam or energy weapons could be viable, though my understanding is that they'd have much the same problems as lasers. Microwave beams might be workable.

The best approach might be electronic warfare, jamming missiles and sending up lots of chaff and IR flares to distract them. You could also consider having the ship's hull be a big Faraday cage and setting off an EMP to guard against volleys, since modern missiles are very reliant on their flight electronics. Though again, what I'm describing is beyond current technology.

[Mando Knight]

If you mean using energy weapons as point-defense guns, possible but not probable. There is a system in development to do just that, but for land use. Lasers can be foiled by bad weather on land; at sea, they'd be worthless on all but the sunniest days.

The YAL-1 (http://en.wikipedia.org/wiki/Boeing_YAL-1) anti-missile laser system is a modified Boeing 747. It's for ballistic missiles, though, not cruise missiles. There's a significant difference in their flight paths.

[Force]

I see. So, what sort of anti-air systems could be used on such a ship, beyond AA guns and SAM launchers?

Jamming. Decoys. An air wing based on the dreadnought in question. Escorts devoted primarily to anti-air defense.

[PersonMan]

You could use relatively small-caliber rapid-fire railguns and coilguns, certainly, and SAMs work. It would be better if your ship had its own air wing so it could fend off threats from further away, though. I don't know enough to say for certain if any particle beam or energy weapons could be viable, though my understanding is that they'd have much the same problems as lasers. Microwave beams might be workable.

The best approach might be electronic warfare, jamming missiles and sending up lots of chaff and IR flares to distract them. You could also consider having the ship's hull be a big Faraday cage and setting off an EMP to guard against volleys, since modern missiles are very reliant on their flight electronics. Though again, what I'm describing is beyond current technology.

I see. Housing jets to fight off other jets makes sense.

I see. Sounds interesting.

[dehro]

I see. Housing jets to fight off other jets makes sense.

I'd say that's a necessity. if you want to play fair...big ships tend to be fought with aircrafts dropping stuff on them... not by sending other ships at them (except maybe submarines)...so you can either allow for futuristic weapon systems that allow you an unfair advantage over the enemy, or there is simply no way that anything existing today in terms of anti-air defence can guarantee you a watertight defence against anything that exists today in terms of airplanes, bombs that can be dropped from one etc etc..

it would also help to understand what the premise is:
is the ship purely devoted to combat? does it have to support a comunity/civilisation/nation? does it have to allow for cargo space for other than ammo, spares and bandages?
is the aim to provide a foothold from which to invade and conquer or to boss it over the seas? or to be self sufficient and protect those aboard from anything that gets thrown at them?
is the premise that the ship is the pinnacle of technology, a few steps ahead of competition, or is it made today, with today's knowledge and with the possible arising of a competitor once the ship is built?
how important is the secrecy concerning the ship's nature and purpose? the bigger you make it, the more manpower, time, resources and sheer size of shipyard you need.. if we're talking realistically, there is only so much you can hide from the public eye, as far as building specifics go.. ..or are we talking of a scenario reminiscent of japanese robot cartoons, with a secret base where the genius in a labcoat works away at his revolutionary big-ass wondermachine?
most if not all of the big aircraft carriers travel with a battle group at all times. does your scenario allow for support crafts with specific tasks?

[_Zoot_]

I hate to be a party pooper but your very much dead.

A ship that size has no hope against todays military's. The first action taken against it would be to launch supersonic anti-shipping missiles; these are almost unstoppable with modern weapon tech and while they can't be outfitted to carry nuclear payloads, they wont have to to destroy the combat effectiveness of your ship.

If you were to sail into US waters, as mentioned above they would first hail you. If you did not comply they would bring every thing they had to get you (Why? because your in the worlds biggest battleship, thats why!). There first action would be to order carrier groups and battle fleets to fire the above mentioned supersonic anti-shipping missiles. That will kill you (they are far to fast to be stopped by CIWS and jamming is not at a level that could prevent them hitting you yet, nor will it be for many years).

If how ever, that did not kill you (for the purpose of this discussion) their next step would be to order ground based attack aircraft to attack you. This you may actually survive, with rail-guns and good enough targeting units you could knock these slower missiles out of the air. But, they might just arm the aircraft with the anti-shipping missiles or simply overwhelm your CIWS (they do of course have at their deployment the US air force, which I'm lead believe to is very big).

If the aircraft don't work (and they might not) they will order in submarines, these will fire missiles this is a problem, most likely not one that your really big boat will live through. But it may as rail-guns have enough force to breakup a missile and may be fast enough to target them all before they hit you.After this they will send the submarines in to torpedo you. As mentioned above, your underwater CIWS is lacking, but you may be able to use depth charges launched from the Doom Ship(TM) to prevent being targeted (not likely, but if you did have an air wing a (and it wasn't just shot down by the carrier group supporting the subs) then they could fend off the subs.

After this you have defeated the United States Navy and Air Force! Congratz!

They will most likely authorize a nuclear strike against you. This will kill you, they will not try and hit the ship with the weapon, they don't need to. They will put the thing within 2-3km of you (underwater, that does most damage to ships) and watch he fireworks. If you survive the first strike and continue to fail to obey there demands they will simply fire more nuclear weapons. You will not survive the first one, this will not happen. The weapons they were using in the early Cold-War could destroy a battle fleet (one weapon), the ones they have now days are bigger then those one.

Right, like I said, I hate to be a party pooper, but a ship that size with that armaments can not work. Your biggest problem is the Supersonic anti-shipping missiles, they can realistically not be stopped by modern defensive technology (or anything else).

[thubby]

this is why hard sci-fi juggernauts tend to be heavily defended from the outside.
satellite anti-missile lasers are the norm iirc.

[paddyfool]

Even in a conventional naval battle, a dreadnought would be taken apart by fighter planes from an aircraft carrier launching anti-ship missles. Battleships have not ruled the seas since WWII.

I would argue "since before WWII". IIRC, the largest and most powerful battleships to see active service in WWII were the Bismarck class. Only two were ever built: the Bismarck herself, which was defeated by biplanes during her first ever operation, and the Tirpitz, which never even left harbour.

[Kcalehc]

What you'd probably want is an Aircraft Carrier-Super Dreadnought combo. A sufficently large air wing on your top deck, plus the big guns of a dreadnought, possibly on lower decks (may limit your elevation for long range however). Unless you can conceive of a covered flight deck with the guns mounted above it (or flight decks to the sides with guns in the center.

You're probably of looking at something like a 'Galactica-of-the-sea' effect to be useful. Still the limitation of being a huge, slow moving target is going to be against you either way.

[paddyfool]

I still say you should weaponise the north polar ice sheet...

[hamishspence]

I would argue "since before WWII". IIRC, the largest and most powerful battleships to see active service in WWII were the Bismarck class. Only two were ever built: the Bismarck herself, which was defeated by biplanes during her first ever operation, and the Tirpitz, which never even left harbour.

Weren't the Yamato class, and the Iowa class, bigger than the Bismarck and the Tirpitz?

http://en.wikipedia.org/wiki/Yamato_class_battleship

http://en.wikipedia.org/wiki/Iowa_class_battleship

Here, at least, the Bismarck class is described as smaller than the others:

http://en.wikipedia.org/wiki/Bismarck_class_battleship

And while the Tirpitz spent most of its time in harbour, it wasn't there all the time, it did make some sorties:

http://en.wikipedia.org/wiki/German_battleship_Tirpitz

[ApeofLight]

Technically couldn't you make a ship that's so big it stops being a ship and becomes a floating continent? Like the size of Australia or more likely the Philippine islands put together.

It's just a matter of getting enough buoyancy for the size and material your making it off.

[The Demented One]

Above somewhere around five solar masses, your ship would collapse in on itself and form a black hole. Does that count as sinking?

[Mauther]

Since your going for a super dreadnaught, throw reality out the window. Keep the rail guns, for coolness factor, and for dispatching crippled hulks that your SD sales past in the aftermath of its slaughters. Create over the horizon offensive punch using ship-to-ship and ship-to-surface missles. Replace the recommended fighter protection with organic drone capability. Anti-air and anti-missle defense would be a cascading effect starting with soft kill attempts outside (hypervelocity missles, short range emp warheads/micro nukes placed on conventional longer range anti-missle delivery vehicles, large caliber anti-missle lasers) moving towards hard kil attempts in close (CIWS for s**ts & giggles, cluster fire SAMs, and kinetic kill vehicles like an upgunned Iron Fist APS (http://en.wikipedia.org/wiki/Iron_Fist_active_protection_system). Add in passive measures like radar deflective decoys, advanced ECCCM (Electronic Counter-Counter-Counter Measures) capable of hacking inbound weapon's software, and even a pseudo shield like a plasma window or high powered repulsion field.

Anti sub, go much the same way. Replace the air drones with parasite subs (drone of course). Put in top class sonar, and ridiculous volumes of decoys. Use towed array weapons clusters loaded with anti-torpedo kill vehicles. Stock up on HK sub drones, ASROCs and sharks with fricking lasers and make the water within 16 miles a no man's land for subs.

Forget stealth. Your building an abomination of the sea, even if you achieve stealth fighter like levels of reduction your SD is still going to show at least as a cruiser, maybe a light carrier. So embrace it. Paint the SOB red and black, fly the jolly roger and blare death metal as it gets under way from Skull Island or whatever volcano lair its been constructed under.

As for the question of how long till it gets detected, about 15 seconds after it sets sail. A ship this size is going to be reported immediately. While the existing satellite tracking isn't fool proof, they will notice a ship the size of Manhatten. As soon as it moves anywhere near a coastline or a shipping lane its going to light up the news feeds. You might gain some time from sheer paralysis assuming no one knew the ship existed. Another advantage would be that modern navies have almost no quick sortie capability. So unless the US Navy was already on alert, it would take days for surface vessels and subs to respond in any reasonable force. Combat aircraft would take hours. Giant doom ships are not a traditional threat to the US so not a lot of resources are set aside for that eventuality.

[Ravens_cry]

Above somewhere around five solar masses, your ship would collapse in on itself and form a black hole. Does that count as sinking?
No, but try getting shore leave.
Damn that event horizon, damn it to hell!

[Eric Tolle]

I hate to be a party pooper but your very much dead.

A ship that size has no hope against todays military's.

You just aren't thinking at a large enough scale.

Largest known iceberg (http://www.nsf.gov/od/lpa/news/press/00/pr0012.htm): 1 170 miles long x 25 miles wide

Pykrete (http://www.combinedops.com/Pykrete.htm): 35 feet was considered enough to proof against any W.W.II torpedo or munition.

So here's my proposal. A pykrete ship, maybe 6 miles long by 1.2 miles wide. All valuable material is inside tunnels hollowed out a half mile deep into the craft, connected to the surface by tunnels.. Turrets for weapons are pop up capsules normally stored a quarter mile below surface, in capsules that have the ability to break through debris and remake their own tunnels if need be. Cooling systems and propulsion are provided by a sufficient number of water-cooled nuclear reactors. It'll be slow as hell, but nothing is going to stop it.

Go ahead. Send your torpedoes and anti-ship weapons and nukes. I'll laugh at them, and I can do it with 1960s technology.

[dehro]

I'd forgotten about pykrete..

trouble is, weapons and their destructive power are a tad more advanced now, and it's hard to say how the material would hold up against them, since it's never been tested that way.
also, cooling systems on an iceberg?:smallbiggrin::smallbiggrin:

[PersonMan]

Yeesh. I leave for a few days and get half a page of responses all of a sudden.

As for the questions:

Effectively, this ship is being built with technology that is a bit more advanced than modern tech, about 10-15 years ahead of now. It is being built by a group of time travelers who will use it to back up a small group of wooden ships their allies are using. They will house it inside an iceberg partially hollowed out and fitted with engines to move more quickly, so it never needs to approach the shore.

[RS14]

The SR-71 was unarmed, it was a spy plane.

Nitpicks:

Its very close cousin, the YF-12 was, however, an interceptor.

The more substantial point is that the SR-71/YF-12 was not, in any really meaningful sense, a stealth aircraft. It had some stealthy features, but with the throttles open, it had all the stealth and subtlety of a flaming elephant at night. Frictional heating and the enormous exhaust streams gave it a substantial IR signature.



As for a super-dreadnaught, you're probably better off with a fleet. If you were to make it work...

You'll need long range offensive capabilities. You might as well upgrade the guns beyond historical levels. Consider something along the lines of Schwerer Gustav or the Paris gun, mounted in a turret and optimized for range. Possibly even consider taking inspiration from modern smoothbore tank armament that is capable of firing missiles. Consider making this weapon capable of MSRI to drop several guided missiles on target at the same time, relatively stealthily, using motors only for the last leg, and thus overwhelming their defenses.


Modern ships have only light armor. Hits will kill them. Caliber doesn't need to be great.

Honestly I don't think conventional artillery has, at modern ranges, any advantage over guided missiles.

Have serious ASW capabilities by means of a large helecopter fleet. Anti-air will need to come from missiles or other planes to be credible.

[PersonMan]

I see. Thanks for all of the help. I'm glad that this time I'm able to stick with the general original idea rather than scrapping it...

[The Demented One]

No, but try getting shore leave.
Damn that event horizon, damn it to hell!
Well. You could just steer it within a Scharzschild radius of shore, and bring the shore leave to you.

[thubby]

Well. You could just steer it within a Scharzschild radius of shore, and bring the shore leave to you.

well then you have the issue of, you know, kidnapping.

[Ravens_cry]

well then you have the issue of, you know, kidnapping.
Then it works to your advantage. You're forced to be tried in absentia and getting you to prison is physically impossible. Just hope they don't have a death sentence.

[Mercenary Pen]

Honestly I don't think conventional artillery has, at modern ranges, any advantage over guided missiles.

Each shot is probably cheaper than a guided missile- and if there's someone having to pay for all this that might make a difference. It's also worth bearing in mind that, with modern tricks such as base bleed (http://en.wikipedia.org/wiki/Base_bleed) or rocket assisted (http://en.wikipedia.org/wiki/Rocket_Assisted_Projectile) shells, you simply don't need the massive cannons to achieve the same ranges as WWII cannons such as the Pariskanonen and the Schwerer Gustav.

[Yora]

Guns would be better for artillery support at land targets, for the same reason artillery is still used in ground combat. But for landing opperations bombers can do the job just as good and are many times cheaper and can also be used for different tasks.

As I see it, there's really no reason to build battleships, and in fact, has never been. All the battleships of the 20th century have turned out to be a huge waste of money and resources, which would have been much better spend in building fleets of smaller crafts. There are good reasons many navies don't have any ships larger than frigates or maybe destroyers.
There's no tactical or strategic reason to have massive battleships, and I think the only reason they were ever build is the same as here. Because someone said "But I want a really really massive ship with huge guns!"
:smallwink:

[Mercenary Pen]

As I see it, there's really no reason to build battleships, and in fact, has never been. All the battleships of the 20th century have turned out to be a huge waste of money and resources, which would have been much better spend in building fleets of smaller crafts. There are good reasons many navies don't have any ships larger than frigates or maybe destroyers.
There's no tactical or strategic reason to have massive battleships, and I think the only reason they were ever build is the same as here. Because someone said "But I want a really really massive ship with huge guns!"
:smallwink:

This is not strictly true. At their time, the HMS Dreadnought, and other similar all big-gun battleships not only had the best guns with the longest ranges, but also the best armour and the fastest engines of anything then afloat. One of the main reasons why battleships never had much impact upon the first world war was due to the decisive action in the war between Russia and Japan back in 1905 where Japan, not considered a major world power at the time, defeated the fleet of one of the major superpowers of the period, Russia. The precise tactics used in that engagement, combined with the cost of the new big-gun dreadnoughts, made admirals unwilling to decisively commit their ships to battle. In my opinion, had dreadnoughts and super-dreadnoughts been more decisively committed to the field of battle, they would have earned the kill ratios that their guns should have been capable of.

As it was, admirals dared not lose such powerful ships, and thus they faded into eventual obscurity as air power began to make its presence felt.