How fast can a Nimitz class aircraft carrier go?

I know the official speed is “30+ knots” and all my sources online say “30+ knots” Ok i know it can do AT LEAST 30 knots but how fast could one go really? I mean we know how much it weighs right? We know its displacement and engine output right? Is this enough information to figureo ut how fast one could go in theory.

http://www.answerbag.com/q_view/5575

You would also need to factor in how much fouling the hull has accumulated since the last time in dock.

That is a really bad answer because it is using so many assumptions and simplifications.

The idea is that a displacement hull produces a wave at the bow which is followed by a through. The bow wave and following through get longer as the speed increases and it gets to the point where the boat is sitting between a wave at the bow and a wave at the stern. At this point if the ship is to increase speed it will effectively have to climb over the bow wave and begin to surf (so it is no loger displacing) or break through the bow wave both of which require exponentially more power (sort of like breaking the sound barrier for an airplane).

For small sailboats the formula given is a rule-of-thumb simplification but the simplified formula is not universally applicable nor does it give a clear point but rather a general idea of where power requirements begin to grow or are already growing fast.

A general formula which would give power vs speed for any hull is practically impossible. Formulas have been developed for different types of hulls which take into account many measurements of a hull, including, obviously, the beam. These formulas can be further simplified by making (big) assumptions like beam in relation to length, power available from the sails, etc. and then the very simplified formula is arrived at. But this formula is obviously not applicable to all hulls.

It is clearly invalid for hulls which are very narrow or very wide. A catamaran will sail faster than its calculated (by that formula) hull speed.

Big ships with bulb bows do not have the same bow wave dynamics (the bulb is there precisely for this purpose and I have been surprised at how little of a wave a huge ship can make).

Sea conditions also make a difference so I suppose the reference would be in calm waters. Waves increase the need for power.

And, again, to really measure the top speed of a carrier we would really need to know the power which can be delivered to the props and the power/speed curve for that particular hull. Applying simplified rules of thumb meant for small vessels makes no sense.

On the other hand, if you tell me how far up in the air you can lift it and then drop it I can tell you with great confidence how fast it will be going when it hits the water.

How fast it can go in theory might depend on how big of a rocket we can build.

Read sailor’s answer again. A boat sitting in water has a maximum speed, no matter how snazzy a rocket you strap onto it. Now, if you had a treadmill…

Sorry but my link says the exact opposite. Given enough power you can raise speed until the boat planes or disintegrates or whatever. Still, a rocket seems a bad way to propel a carrier unless you want to propel it upwards in which case you can get it to go pretty fast by just dropping it from a certain altitude.

Oh, and just in case anyone didn’t understand why the reference doesn’t give the exact top speed of the carrier, the exact top speed is classified information. I’m sure there are lots of navy guys and a few Russian spies who could tell you the exact top speed, but they won’t.

You might be surprised.

I was in the engineroom of my ship (not a carrier) for a couple of speed runs.

I know exactly how many shaft RPM we were running, what percent reactor power were pulling down, and how hot everything was, and how loud the main turbine was.

I don’t know how fast we were going. Just the same in excess of 30 knots that you’ll see on Wikipedia and other cites.

Some people knew. The OOD, I imagine, the QMOW, and a few others on the bridge. But it was never widely disseminated. Respecting the “need to know” is a lot better at protecting secrets than telling someone that they can’t mention what they know.

Was it fast enough to let the captain go water surfing behind the ship?:smiley:

Yeah, I was thinking of the ridiculous “up in the air” or “out in space” ideas, in addition to the “forced disintegration in the water” one.

That needs a moderately large rocket, though …

I knew a Navy E-6 who was on the USS Ronald Reagan (which is Nimitz class) and he told me he knew for sure it could go 55 knots. I have no idea how he knew that, but I suppose you pick things up after being on a ship long enough.

A co-worker was on the Nimitz when it responded to some emergent situation somewhere (it was a while ago, so I don’t remember what situation). I remember he said that they had just passed an island in the Sulu sea when they cranked up, took off, and left all their escorts behind.

They arrived on station at some other place, in the Indian ocean I think, in a specific amount of time. My co-worker found the distance between the two points, did the math given the time involved, and came up with a speed of over 60 mph.

They’re plenty fast, all right. BTW, you can water ski behind most Navy ships, the problem is in ‘getting up’. The acceleration isn’t quite the same as a speedboat.

30 knots? Hell yes.

[quote=“Danalan, post:14, topic:466426”]

A co-worker was on the Nimitz when it responded to some emergent situation somewhere (it was a while ago, so I don’t remember what situation). I remember he said that they had just passed an island in the Sulu sea when they cranked up, took off, and left all their escorts behind.

They arrived on station at some other place, in the Indian ocean I think, in a specific amount of time. My co-worker found the distance between the two points, did the math given the time involved, and came up with a speed of over 60 mph.

[QUOTE]
I doubt it. But I can assure you the Russians can also divide and know full well what kind of speed American Navy ships have done.

I find the concept that "the top speed is classified information a bit silly. IMHO it is not so much classified information as much as irrelevant and non-existant information. Just like asking how fast can a certain car go or how much weight can a certain airplane carry. The answer is “it depends”. The reason they say “30 knots+” is not because they want to keep it a secret but because that is the best definition which can be givern. A ship is not going to have a hard figure which can be said is its “top speed” because the speed it can achieve depends on so many factors, including, the state of the sea, the state of the hull, how loaded the ship is, for how long you can maintain the powerplant power output etc. A ship might be able to maintain a certain powerplant output for say, 15 minutes, somewhat less for 30 minutes, somewhat less for 1 hour, somewhat less for 4 hours and somewhat less indefinitely. Even salinity and the wind and state of the atmosphere will have an effect. There are just too many variables. Asking for a top speed figure with any more precission than “30+ knots” is kind of meaningless and open to speculation in the same league as “can a Boeing 747 do backflips”.

[quote=“sailor, post:16, topic:466426”]

That’s hardly the case. While a request for “top speed” might not be answerable with absolute precision, and is surely dependent on a number of factors, a reasonable assumption could be made that the questioner is asking for a general sense of how fast it go under under near ideal conditions. If the top end speed is apparently up into the 50-60 mph range under ideal conditions this is a perfectly acceptable answer.

Well, 50-60 mph I very much doubt. 60 mph is 52 knots and I very much doubt it. Any suggestion that it can do 52 knots under any circumstances requires very serious support. I think when they say 30+ knots that is exactly what they mean and I do not think they are intending to conceal the fact that it can do 52 knots.

Indeed.

I was in the engine room on the Nimitz and knew exactly the numbers you describe about the power plant, but never had a clue about what it meant in actual speed.

Kind of like asking how deep subs can go, I guess. I remember asking one of our teachers in nuke school the sub-depth question (he was a sub sailor) and his answer led me to understand that this was the one question that was never to be asked of a submariner. I imagine he knew the answer since he was a lieutenant commander – an officer and not the greenest one at that.

A US aircraft carrier left its escort behind?
Wouldn’t that make it rather vulnerable to the host of threats which its escorts are expected to nullify?
Is your friend the type you’d trust with your life to be honest?