Backward x 2 CV Photo

[reg113]

Worked nights aboard CVAN 65 in the early 70's. One "morning" was going to work in shop on hanger deck from rack on 03 level, sumpthin didn't feel right. Passed the #1 elevator and the sea was going in the wrong direction. Decideed to go up to flight deck to see what was happening. Came out on catwalk and immediatly got drenched. Captain was doing a speed run in reverse and the "bow wake" thrown up by the stern was getting the whole flight deck wet. What a sight! Scuttbutt was we were doing 22 knots....

[Apollo11]

Hi all,

ORIGINAL: reg113

Worked nights aboard CVAN 65 in the early 70's. One "morning" was going to work in shop on hanger deck from rack on 03 level, sumpthin didn't feel right. Passed the #1 elevator and the sea was going in the wrong direction. Decideed to go up to flight deck to see what was happening. Came out on catwalk and immediatly got drenched. Captain was doing a speed run in reverse and the "bow wake" thrown up by the stern was getting the whole flight deck wet. What a sight! Scuttbutt was we were doing 22 knots....

Aren't the CVN-65 Enterprise speeds still top secret? [8D]


Leo "Apollo11"

[reg113]

30+ Not sure how much extra you get for a +...

[ChezDaJez]

Aren't the CVN-65 Enterprise speeds still top secret?

Technically, they are still secret. However, I remember a time when she came through our sonobuoy field at high speed. Measured her prop RPMs and computed a speed based on TPK. I had to recompute her speed several times before I believed it. It was "somewhat" in excess of 30 knots.

Chez

[diesel7013]

CVN's can scoot upwards of 40 - but don't tell anyone...[:D][:D][:D]

[witpqs]

ORIGINAL: Feinder

Hm. Kinda surprised it let me remote link an image.

This is an avenger off of Hornet.



-F-

Great picture - thanks!

[Ian R]

ORIGINAL: diesel7013

CVN's can scoot upwards of 40 - but don't tell anyone...[:D][:D][:D]

So that must mean in a 70s/80s scenario of a nuclear BG of say Enterprise, Truxtun, Bainbridge, Long Beach and Arkansas, the BG can far outpace (and outlast) conventinally powered TFs and most SSNs as well.

Adm Rickover's views come into context.

[Raverdave]

ORIGINAL: ChezDaJez

Aren't the CVN-65 Enterprise speeds still top secret?

Technically, they are still secret. However, I remember a time when she came through our sonobuoy field at high speed. Measured her prop RPMs and computed a speed based on TPK. I had to recompute her speed several times before I believed it. It was "somewhat" in excess of 30 knots.

Chez

It is the hull design which limits the speed of the CVN (of course there is also the small issue of the shaft bearings
).....they have the raw power to go faster.

[Apollo11]

Hi all,

ORIGINAL: Raverdave

It is the hull design which limits the speed of the CVN (of course there is also the small issue of the shaft bearings
).....they have the raw power to go faster.

And that's why CVN-65 Enterprise is still believed to be champion - her hull was different than those follow up super carriers (Enterprise is one and only in her class)...


Leo "Apollo11"

[witpqs]

If you can explain it to land-lubbers: How is her hull different?

[herwin]

ORIGINAL: Coach Z

I know they were designed to go in reverse as fast as forward to allow for launching and retrieving planes in both directions. But from what I know it was never done in combat or non-safe settings, and that the forward arrestor wires were removed fairly quickly when in  fleet service.

The early Essex class carriers also had a hanger deck catapult...

[wdolson]

Aren't the CVN-65 Enterprise speeds still top secret?

ORIGINAL: ChezDaJez
Technically, they are still secret. However, I remember a time when she came through our sonobuoy field at high speed. Measured her prop RPMs and computed a speed based on TPK. I had to recompute her speed several times before I believed it. It was "somewhat" in excess of 30 knots.

Chez

I know someone who was on the USS Gearing during Vietnam. He said they were on their way home and were getting topped up by the Enterprise 100-200 miles off the west coast. Enterprise was headed to San Diego and they were headed to Long Beach. He said standard procedure was for the smaller, more nimble ship to pull away first and go to full power. They started running up to 30+ knots and the Enterprise broke away from them and left them sitting there like they weren't even moving. He knew they were doing at least 30 knots and the Enterprise was doing at least twice their speed when he last saw her. He said there was a rooster tail coming off the back taller than the flight deck.

I don't have any way of verifying it, but he never struck me as the sort of person to tell tall tales.

Bill

[Raverdave]

 
Hull speed

From Wikipedia, the free encyclopedia
[/align]Jump to: navigation, search[/align]Hull speed is a common rule of thumb based on the speed/length ratio of a displacement hull, used to provide the approximate speed potential (i.e. maximum speed possible) of the hull. It is the speed of a deep water wave whose wavelength is equal to the waterline length of the hull. The most commonly used hull speed constant is the wave propagation speed for the hull length, and it serves well for traditional sailing hulls. In English units, it is expressed as:

Or, in metric units:

where "l" is the length of the waterline (LWL) in feet or meters.
Hull speed is typically not a term used by naval architects (they use, instead, a specific speed/length ratio for the hull in question) but is often used by amateur builders of displacement hulls, such as small sailboats and rowboats.
The concept has to do with the effect of drag from the water on the hull. With all else being equal, a longer boat will have a higher hull speed. In yacht racing this is demonstrated by looking at handicap ratings such as PHRF; generally speaking longer boats have higher handicap, although there are other factors.[/align] 
 
http://en.wikipedia.org/wiki/Hull_speed

[herwin]

So she had picked up her skirts and was running?

Ships at those speeds are power-limited. The power goes up as the fifth power or so of the speed, and even a nuclear power plant has its limits.

[Raverdave]

Yup you are correct.....but it is also the length of the hull that helps in the speed, don't ask me why but the longer the hull the faster you can go.  I did have it explained to me once but all I remember is the headache that it gave me.[:(] 

[Terminus]

ORIGINAL: wdolson

Aren't the CVN-65 Enterprise speeds still top secret?

ORIGINAL: ChezDaJez
Technically, they are still secret. However, I remember a time when she came through our sonobuoy field at high speed. Measured her prop RPMs and computed a speed based on TPK. I had to recompute her speed several times before I believed it. It was "somewhat" in excess of 30 knots.

Chez

I know someone who was on the USS Gearing during Vietnam. He said they were on their way home and were getting topped up by the Enterprise 100-200 miles off the west coast. Enterprise was headed to San Diego and they were headed to Long Beach. He said standard procedure was for the smaller, more nimble ship to pull away first and go to full power. They started running up to 30+ knots and the Enterprise broke away from them and left them sitting there like they weren't even moving. He knew they were doing at least 30 knots and the Enterprise was doing at least twice their speed when he last saw her. He said there was a rooster tail coming off the back taller than the flight deck.

I don't have any way of verifying it, but he never struck me as the sort of person to tell tall tales.

Bill

Except for the fact that he told you the Enterprise was doing 60+ knots. Not possible, even with eight nuclear reactors.

[String]

Here is a good article which debunks the many myths about CVN speeds.

edit: This one also explains some stuff.

[Speedysteve]

ORIGINAL: Terminus

Except for the fact that he told you the Enterprise was doing 60+ knots. Not possible, even with eight nuclear reactors.

LOL T[:D]

[wdolson]

ORIGINAL: String

Here is a good article which debunks the many myths about CVN speeds.

edit: This one also explains some stuff.

It all makes sense. Another bit they don't talk about is that propellers get less efficient the faster they turn. In air, they get separation at the tips and less of the propeller is biting the air. This is the reason propeller planes can fly faster than the speed of sound in level flight.

In water, I would expect similar dynamics with the water. Spin the propeller fast enough and it ends up churning foam. Though I'm sure the hull can be crafted to minimize turbulance ahead of the propellers.

I never had to take a full fluid dynamics course (Electronic Engineering major), so I only learned the basics from some other engineering courses. (I did have to take several Mechanical Engineering courses.)

I've heard a lot of stories about the speeds of the CVNs over the years. This one was from an eye witness, but while I don't think he made anything up, he probably mistook the accelleration for high speed. I'm sure that anything the size of the Enterprise moving 30+ knots fairly close to you would be quite impressive. I've seen a B-17 do knife edges at a couple of hundred feet and it was far more impressive than a P-51 doing the same maneuver.

Bill

[Apollo11]

Hi all,

ORIGINAL: String

Here is a good article which debunks the many myths about CVN speeds.

edit: This one also explains some stuff.

Interesting - thanks for he links!


Leo "Apollo11"