From the first linked article, for the Iowas, the required power went up by the cube of the speed. Being very generous with the Enterprise’s power and alloting 300,000 shp, I get a speed, if that power were applied to the Iowa’s screws, of 39.3 kts. Now, Enterprise had less drag, due to its higher length, than Iowa, but enough for it get to 45 kts+? I’d think you’d need some form of air cushion or planing effect to lower drag sufficiently to do that. Let us all now visualize a 100,000 ton+ carrier as a hovercraft…
I can believe 42 kts. Maybe. But I’m quite skeptical about 50 and more.
Not saying that you’re lying or mistaken, Cheshire; just that I’m missing something that explains that discrepancy between what you observed, and what reading about the basic math and behavior for other vessels tells me should be happening instead.
EDIT: Or, I could have just linked to this article at Navweaps, discussing CVN top speeds. Apologies if it’s already been mentioned in the thread.
The compressability of water has absolutely got to effect the potential top speed of any ship. (I can’t imagine the bow wave on a 65 knot carrier. Good thing those cranials come with goggles!)
I went through the officer side of the Navy nuclear power training program years ago. As I recall, we lost about 10-20% of our class in Navy Nuclear Power School, and a much smaller percentage at prototype (the follow-on hands-on training at an operational prototype reactor plant). At nuclear power school, we had something like 10 courses, and the second failure in a course meant you were gone. Everyone also had to pass the comprehensive final exam.
Our loss percentages were likely lower than the enlisted side because of more extensive screening, including a technical interview process in Washington, D.C., followed by a personal interview with the four-star admiral in charge of Naval Reactors (i.e. ADM Rickover’s successor), plus we were all university graduates, of course.
That was not to say that the course was easy, by any means. I personally didn’t find the material as difficult as my university education (B.S. in Chemical Engineering), but there was a tremendous amount of memorization required.
And like OtakuLoki said, everyone seemed to hit a difficult topic or three. For me, it was “Reactor Dynamics and Core Characteristics” (i.e. “RD-Core”). (It’s kind of amazing how I can still remember the course title like it was yesterday.) I ended up passing the course, but got my one and only exam failure on the first exam.
I also found the electrical engineering course to be difficult, especially when we got to three-phase power.
I didn’t have too much trouble with the other courses. As a chemical engineering major in college, I breezed through “Heat Transfer and Fluid Flow” as well as the chemistry course. I also didn’t have any trouble with the math course, nuclear physics course, health physics course, materials course, or “Aspects of Reactor Plant Operations.”
All in all, I found the training to be excellent. In many ways, it was far more practical and useful than my university education.
What kind of questions were you asked during the interview with the admiral? I’m more looking for a sense of what an interview with a full admiral is like than the technical side which I couldn’t understand anyway.
During the training, did they sleep deprive you or create stressful during practical tests?
What helped you with the amount of memorization required?
I was a guest of VA-75 in Feb. '96, and the pilots told me what all the numbers in the display in their ready-room was on my first day aboard. The next day, I was out smoking, looked down, saw the size of the wake we were kicking up, and said “Holy Shit! We’re really hauling ass! Must be doing 40-45kts!” I immediately tossed my cig, and went to the ready-room to look at the ship’s-speed on the data display, and saw 42kts. Nice guesstimate for a landlubber. I mentioned it later to one of the officers out in the smoking area, and he told me the 50kts story. I don’t know him, never met him before that evening, and never saw him again after that. He was an LTCDR, so I presumed him to be reasonably honest and too experienced to be mistaken, but I can’t vouch for him. I just took him at his word. My guess of 65kts was based on the fact that if they’re going to stop telling everyone on the ship who’s not cleared to know the real top speed when the ship hits 50, there must be a tactically significant additional capability, which I guessed to be about 15 extra knots. All that said, you may very well be right, since I can personally only testify to 42kts from my own direct observation.
[amusing story from that cruise. Hijack, so skip if you’re not interested]
If you’re ever a guest on a US Navy ship, don’t ever wear a light blue, short-sleeved, button-down shirt with dark blue jeans (the colors and roughly the style of the enlisted uniform). It doesn’t matter that you have long hair and a beard, the officers will only see what you’re wearing and will plow into you, expecting you to get out of their way. I was going down a passageway, and an officer was coming the other way. He wasn’t slowing down as he got close, as us civilians would do. At the last instant, I figured out why. He saw the color of my clothes, and expected me to get out of his way. I stepped aside into the space between the steel frames at just the last instant, so he didn’t have to slow down, and I was only delayed by the time it took him to get through the frame-space we were in. About 1 second. I watched officer-enlisted interactions after that for a while, and found out that I had accidentally done it just right. Nobody slows down, but the enlisted guy gives way at the last instant, just long enough to let the officer pass, and not a fraction of a second more. [/hijack]
Just read your link. Perhaps the LTCDR I talked to was, in fact, repeating the urban legend mentioned in that article. I don’t know, and have no way to find out, 16± years after the fact. As I stated in my previous post, I can only attest to 42kts from personal observation. That is, in fact, how fast the ship was going. They wouldn’t, and couldn’t, derate it (as far as I know). But none of the officers on the officers’ smoking sponson (I didn’t, but could have if I was willing to wait in line, smoke on the enlisted smoking sponson. Hey, if you’re the guest of an officer, you use the officers’ head, etc. You don’t cut the enlisted line. Ever. Even though you’re allowed to do so. That’s how you piss off everyone around you.) at the time seemed to think we were going at a particularly remarkable speed. Take that for what it’s worth.
You’d be amazed at what that looks like. Especially since you have to be held by the anckles, and trust the people who are keeping you from falling somewhere in the vicinity of the anchors or be stupid enough to trust your brother, or get cut by the bow. See where that is? I was suspended by my feet out the hole on the other side. And my ‘brown-shoe’ brother was arguing with a ‘black-shoe’ deck-ape, and they were both advocating for dropping me!! Gee. Thanks, asshole…
Thanks for the interesting anecdotes. Sea stories are usually fun to read. And you certainly couldn’t get a better view of the bow wave… Being a civilian, I’ve only ever been on a Perry, and that only during a tour. The PO3 or 2 giving the tour just shook his head and glared when I asked him about convergence zones and just how far the ship’s sonar suites could hear. Guess I could have enlisted if I wanted to know bad enough…
Thinking much later after my post, I was wondering if what you saw was a measure of the wind speed down the deck? I can easily imagine the carrier going to flank for flight operations, which, per the link on speed I had up earlier, would be ~30 knots, and doing that into a 20 knot head wind. That’d make the wind over the bow ~50 knots, and knowing the wind over the bow would be a quantity that the crew would want to readily know. Also, I don’t know at what wind speed the carrier would cease flight operations, but greater than 50-60 knots over the bow would make things interesting for the deck crew, I’d think.
Whether 30 or 40, that’s certainly moving along for a 100,000 ton+ vessel. Spend a few hundred billion dollars, and it’s amazing what you’ll come up with.
Too late to edit, something else in the post I was replying to worth commenting on:
I’ve got nice pictures of me and several others leaning back at about a 20 to 30 degree angle into a +50 knot wind over the flight deck. Too bad it was on film, before I got a digital camera, and I don’t know where the pictures are. It was a really cool pic.
It was a data display for naval aviators in an aviation squadron ready-room aboard a naval ship! It was all in knots. Why in hell would it be in anything else? Why would you think it might be in any other units?
USS Enterprise cost $451.3 million, according to Wikipedia. That’s not a few hundred, that’s 0.45, less than one.
Sorry to nitpick, but I see a lot of cases of runaway inflation in describing military spending. I recently had to go look up the cost of the F-117 Nighthawk stealth aircraft after a Military Channel show referred to the one that got shot down as a “multi-billion dollar aircraft.” Not even close – F-117s cost about 42.6 million each, if Wikipedia is to be believed.
I was referring to the US Navy as a whole, and the development of naval nuclear power and naval aviation embodied by USS Enterprise, not the cost of one particular unit within that set. Add those development costs so that you can get in a position to build the first CVN, and I don’t think 100s of billions is that out of line. Sorry if I was ambiguous.
FWIW, $450 million strikes me as about an order of magnitude off the replacement cost. Granted, those were 1957 dollars, but still. This article from 2005 on procuring the CVN-21 class seems to agree and then some. Jesus, 13.7 billion for CVN-78?! Although that price dips quite a bit (~7.9-8.1 billion 2008 USD) for each successive unit. Even if you account for inflation per the CPI (though thoughts of a “consumer price” seems silly, when talking about a nuclear powered carrier.), I only get a 2011 cost to build USS Enterprise of ~$3.5 billion. Given the defense rag cite, I think the USN and Pentagon as a whole would be thrilled to get an Enterprise for that figure. So, not an order of magnitude greater to do it today, depending on how you parse the inflation and costs figures, but still quite a bit more than it cost to build the Big E back in the late 50s.
Edit: I’m pretty sure the CNN crew mistook the F-117 for the B-2, which is a multi-billion dollar a/c. (2 of them, IIRC). Though, if you throw in the R&D costs of the stealth program, then apportion that to each F-117, I can perhaps see a dollar figure in the billion range.
I think the nuclear power training was more challenging than standard undergraduate university fare.
I base this on having gone to college after leaving the Navy and simply breezing through four years of nontrivial coursework with a four point, just doing what the Navy taught us to do.
I used to smile when I heard university classmates grumbling about the homework load or the amount of rote memorization. I thank the Navy for teaching me how to study and giving me a good “high water mark” for heavy course load that kept things in perspective.
Fascinating discussion. See the latest issue of Naval History magazine for some sea stories by USS Enterprise personnel over the years. I hadn’t realized that JFK, LBJ and Hubert Humphrey all visited her early in her service.
For what it is worth, most ships shudder at their top speeds. The USS Ranger (CV-61) would start shuddering at over 30 knots pretty badly.
Worth noting as this thread is pretty old, The Big “E” just completed her final sea duty. She is headed for the scrap yard now as by the time they remove the 8 reactors there is not enough ship left to be a museum. It was announced one of the Ford Class carriers will be named the Enterprise. She is currently scheduled to launch around 2025 as CVN-80.
Not really; the bulk elastic modulus of water is so high that compressibility isn’t taken into account (you do have to worry about it in air at trans- and super-sonic speeds, but that’s another matter). You might be thinking of the wave-making drag, which, along with frictional and spray drag, are limiting factors to the speed of a vessel, but these have nothing to do with compressibility.
