Why has there been a general 30kt speed limit on the vast majority

>>29732316
Hydrodynamics and hull speed. Hull speed is proportional to the square root of water line length. So longer goes faster, but not by much. Pushing a ship over hull speed takes a lot of power.

physics

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Shimakaze was getting 40 knots back in the 40's

>>29732316
>30kt
Public knowledge has most modern war ships at 30kt. But unofficial reports from civilian ships with radar have reported speeds as high as 50+kt for a nuke carriers.

>>29732526

I really doubt that

>>29732526
Lol no

>>29732526
>>29732548

People who are much smarter than me have calculated top speeds of the Nimitz class to be roughly 40-43 knots (maybe a bit more), based on the hull design and power available. I don't know if they've ever gone that fast, but it is at least theoretically possible.

Likewise, US SSNs are likely able to go quite a bit faster than the stated 25 knots.

>>29732602
And of course now that I've said that, I've found other people who are again much smarter than me saying that no, the max speed should be less than 33 knots.

But if 30 knots is fast enough for operations in dead calm waters, then that should be fast enough in general.

Nuke carriers tend run at full speed into wind for launching aircraft. But not much over 35 kts.

There really is no need to go any faster than your escort

also, two 15kt or even 3 10kt warships are more cost effective than a single 30kt warship

A trimaran design like LCS wiuls have better top spwed compared ro conventional layout ship

>>29732646
>There really is no need to go any faster than your escort

Guess what's holding them back?

hydrofoil carrier/destroyers when?

>>29732672
are you okay?

>>29733644
might be a mild stroke

>>29732646
>There really is no need to go any faster than your escort

Rather, there's no need to go any faster than "Five days across the Atlantic" because no matter how fast you go, you'll never be fast enough to outrun a ASM

>>29732672
Lol Jesus Christ anon.

>>29732316
There wasn't one, really, but most larger ships didn't travel much faster than 30 kts since that was the point of decreasing returns. Adding another 100k horsepower wouldn't give you another two knots.

How about we replace warships with massive ground effect planes

thoughts?

>>29732672
See a doctor. You're having a stroke.

>>29735840

It's useful in other ways.

Ex. A RORSAT passes overhead, and spots the CBG.

CBG knows the satellite is overhead, and once it goes over the horizon, turns from their old trajectory.

Say the CBG has 4 hours (not unreasonable), before the bombers show up, it can displace itself 140nm in any direction, giving a search area of 60,000 NM^2.

You don't launch ASHM's without knowing the CBG's exact location, so that's more time added to the kill-chain for the ASHM bombers. not only time, but also a bigger area to hide and plan counterattacks with.

With the slow Brit carriers, the search area goes down to 30,000 NM^2. But then again, they were never designed for that specific threat.

The other thing that running at 35 does is that it allows you to outpace submarines significantly. The new Russian subs can stay pretty silent at 20 knots, so with 25 knots you can't pull distance on them well. If they SSN want's to tail a 35 knot CBG, it has to go loud and make itself audible to the CBG's own SSN and ASW escorts.

>>29732430
/thread

cause they spent the money on the F-35 instead

>>29732526

The State of Maine (officially a whale research vessel) and its sister the State of California with their original diesels could reach 40 knots.


The State of Maine though since the Maine Maritime Academy has taken control of it has had its twin V-12 diesels removed and a single inline 6 with an electric secondary motor installed, with both running it can push at 26 knots.

It also boasts a variable pitch propeller. A very expensive item for a whale research vessel. And considering its official top speed is 20 knots. These two "whale research" ships are in fact not what they seem to be.

>>29736934
What was the name of those sneaki-breeki so or boats? SURTASS maybe?

Odds are that's what it is.

>>29732473
>Shimakaze was getting 40 knots back in the 40's
I googled it and all I found were pics of some anime character. WTF?

>>29737089

turn back now, before it's too late

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>>29737089
Oh you sweet summer child.
Best sloot comin' through

I'd love to share the top speed of a Nimitz, but I have an aversion to black Suburbans with blue lights on my front lawn.

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>>29737089
welcome 2 the innanet

>>29732652
1,000 piston powered dive bombers are more cost effective then 1 B-2.

>>29737217

It's pure physics, you can only push a literal brick through the water so fast.

>>29737089
You must have mistakenly put "best girl" into the google search, here try "shimakaze"

Is there any real point? Genuinely curious

First strike would be conducted by an ICBM, air strike from a strategic bomber/long range cruise missile etc

whether the CSG is there in 5 days or 7 does it really matter?

It would stand to reason as new ships come online, speeds will increase marginally, until in 50 years or so as materials and designs advance yes in fact warships will be significantly faster if doctrine includes an increase in speed

Speed will not outrun a torpedo or strike fighter, hide you from radar/sonar etc. so the purpose for speed in the case of, well, everything is getting you point A to B

When air assets get from A to B in a tiny fraction of time for first strikes and such, the marginal increase in speed that *could* be gained with slightly faster warships literally doesn't matter in the grand scheme of things


I am no expert, and am talking out of my ass. If you have a reasonable argument otherwise feel free to tell me, or point out something I may have missed. I am not convinced I am right, nor am I trying with real effort to convince others just my 2cents

>>29737620

see >>29736632

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The USburger military refuses to adapt its air-launched cruise missiles to an anti-ship role because the idea frightens Burger Admirals since ships can be attacked well beyond a Burger Carrier Strike Group defensive perimeter.

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OP, I know you said MOST warships, but here, the Avro Arrow of the Seas. At least she didn't get dismembered. 80 knots. We'd love this one today. Eat this Somalian pirates! Who's the captain now!

>>29739916
>the Avro Arrow of the Seas
So an overhyped piece of shit that Canadians nonetheless cling to as DA BEST THING EVER, EH?

>>29739344
Hi there Comrade Vatnik. The US Navy is many things but an ostrich it is not. Nice try though.

>>29737051
SURTASS is the name of the sonar system. We know that it is mounted on the USNS Stalwart and Victorious, as well as the JDS Hibiki and I think the Harima. It started with an H, in any case.

>>29739916

So the only way to go fast in the water is to get out of the water?

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>>29737128
A cute mom.

>>29732418
This, it takes a lot of fugging power since power requirements to propel through a fluid isn't linear, it's either square or cube, I forget.

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>>29741977

Air is a fluid.

>>29742264
Which is why aerospace engineering is so difficult. Fluid dynamics are a bitch.

Why don't we put big foils on the bottom so they can lift out of the water going high speeds or something?

>>29742273

Yes, but I mean what power requirement are we comparing ships to that are a square root smaller?

Even cars have to travel through a fluid.

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>>29742264
with much lower density and viscosity, yes.

>>29736523
No. Or rather the Russians found the upper limit of ground effect with a cold war amphibious bomber that never seemed to pan out.

>>29732652
That's just dumb.

>>29732473
That was a test run done while she was completely empty wit no wartime load.

>>29737089
First time here? By here I mean the internet, not 4chan, not /k/.

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>>29736934

So much fail in one post...

>The State of Maine (officially a whale research vessel) and its sister the State of California with their original diesels could reach 40 knots.

Nope, you even got other ships name wrong.

Those were oceanographic research vessels built for US Navy. In military context that means making maps of sea floor. Accurate maps are extremely useful, especially when it comes to submarine and anti-submarine warfare.

Engine change happened because one originals fucking blew up and those were maintenance nightmares. A school ship meant to train merchant marine sailors doesn't need expensive acoustically isolated engines to conduct accurate sonar surveys of ocean floor and such ship stationed on US coast doesn't need capability relocate other side of globe fast on regular basis.

Original 20kt speed is relatively fast for a survey ship, now it goes 16kt. Those usually go bit slower as it's more economical.

>It also boasts a variable pitch propeller. A very expensive item for a whale research vessel.

Nope, pic related... It's a fucking podded thruster with variable pitch screw for a fucking cruise ship. Where is your god now? Fuck off to /x/ to talk about fucking contrails and conspiracies. Also maps ain't whales.

>>29736523

Can't stay on station to monitor everything and can't sealift 'muhreens heavy armor or at least substantial amount of heavy armor. Expensive as fuck as well.

>>29741899
Yup, also the reason speed boats lift the front, air resistance is alot less than water resistance. So the less hull you have in the water the less resistance there is and the faster you can go.

>>29746643
Azipods are the sex.

>>29739344

What would they sink with those big ALCM's?

The Soviet Navy? with it's zero carriers, zero CAP, and non-integrated air defense?

Harpoons do the job just fine for a lot cheaper.

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>>29737089
Oh boy...

>>29739344
> .5 rubles have been added to your account

>>29749041
Chinks are finally producing plenty of frigates and destroyers to sink

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>>29749041

>>29745779

A record's a record

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>>29737089
>mfw anime boats are taking over real boat google searches

>>29736523

three words: iowa class hydrofoil

>>29737089
Soon... One of us. Gooble-gobble, gooble-gobble. One of us.

>>29732526
>But unofficial reports from civilian ships with radar have reported speeds as high as 50+kt for a nuke carriers.
Bullshit.

http://www.navweaps.com/index_tech/tech-028.htm

>>29737620
Carriers are positioned to geopolitical hot-zones, sometimes in emergency situations at higher speeds then their escorts can match (after 9/11 and in some disaster releaf missions carriers have outpaced their surface group and gotten into position days faster then their escorts).

In the even of world war 3 there's significant tactical advantage to carrier's speed and range.

>>29749206
You don't need ALCM to sink the PLAN, sea state 3 would do it.

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>>29749168

>>29732316
This is completely irrelevant but I just realized that if you read 30kt as 30k tons, it could be interpreted as 30,000 tons or 30 kilo-tons and both are accurate.

...I need to sleep.

>>29732473
>Shimakaze was getting 40 knots back in the 40's
This a sfw board

>>29754026
nonsense, pop another addy and stay up another 16 hours

it's what I'm doing

>>29732418
>Pushing a ship over hull speed takes a lot of power.

No amount of power will get a displacement hull above hull speed - the energy just creates a bigger bow wave

The only way to exceed hull speed is a planing hull

Planing air craft carriers, now there's a thought...

>>29759947

Forgot to add, max hull speed = 1.2 x square root of the waterline length (in metres)

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>>29732418
so why not make it faster?

>>29759947
Llike the sound barrier enough power can overcome hull speed. It's just uneconomical.

>>29760227
What about water's effective incompressibility?

>>29736528
kek

>>29759947
>>29760227
>>29760457
wouldn't the hull just crumble if you try to go 2fast2furious?

>>29732316
Hahahahaha.

Its "30+" anon ;)

Most us warships will go well above their so called offficial speed when needed.

>>29760227
>Llike the sound barrier enough power can overcome hull speed. It's just uneconomical.

No it can't - it just creates a bigger and bigger bow wave. Water is incompressible, air isn't

>>29765541
by almost 5 knots sometimes even

>>29760457
>>29765824
If it weren't just bloody energy intensive but outright physically impossible as you claim there would be no way bullets fired underwater can exceed their hull speed. But they do. And the cross section of bullets is very similar to the waterline of a ship.

>>29765843

They also travel orders of magnitude less distance than they normally would.....

>>29765890
>moving the goal post
Yeah, of course, because water is denser than air, hence more drag and more deceleration. But don't distract from the original point. If it was literally physically impossible to exceed hull speed and not just so energy intensive to the point where it's simply uneconomical, they should never be able to accelerate beyond their hull speed in the first place.

>>29765843
>But they do. And the cross section of bullets is very similar to the waterline of a ship

Go to a pool. Walk through the water - quite easy. Now try and RUN through the water. Simple fact is that the faster you go, the resistance increases disproportionately. Applies to bullets too-

http://uk.businessinsider.com/what-happens-when-you-shoot-a-gun-underwater-2016-1

>>29765969
and?

>>29765454
Only if it runs into resistance

>>29765953
>they should never be able to accelerate beyond their hull speed in the first place.

Watch some rich guy in his gin palace. As they accelarate, the bow wave gets bigger and bigger and the stern of the boats squats. This is the boats trying to climb its ever increasing bow wave. In a planing hull the boat finally "unsticks", rises over the wave and starts to plane. Unless the hull is specifically designed to do that, the boat cannot ever climb its own bow wave - with more power it just gets bigger and bigger

There are some very special hull forms which are the exception - generally when the beam is less than 6% of the water line length, but they wouldn't make good carriers, would they?

>>29765995
You're missing the point.

>>29765824
Water is displaceable, which is equivalent to the "compressibility" of air in this case due to one key difference between these otherwise-similar phenomena.
>Gravity waves != pressure/shock waves

>>29766002
>You're missing the point.

Which is?

>>29766007
learn to fucking read you dumb cuck

>>29766005
>Water is displaceable

Yes it is. However, its NOT compressible, so where does the "displaced water go? - it's constrained by more, incompressible water, so the only place for it to go is up- hence the bigger bow wave. You're shooting down your own agrgument

>>29765995
>In a planing hull the boat finally "unsticks"
The more accurate way of putting it is that hydrodynamic hull lift begins to take precedent over hydrostatic displacement in countering the weight of the vessel, and proportionately to the reduced displacement the wave-making resistance decreases accordingly.

>>29766007
The rather academic discussion of pure possibility/impossibility. I am well aware that nobody outfits his ship with that much power to overcome hull speed without taking other, easier shortcuts, like a planing hull, hydrofoils etc.

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>>29766012
>learn to fucking read you dumb cuck

No YOU learn to read you ignorant fuck

https://en.wikipedia.org/wiki/Hull_speed

>>29766007

hair splitting

>>29766056
>hair splitting

LMFAO

Yeah, whatever

>>29765454
In the mythology aboard the Enterprise (CVN-65) she used to have speed screws (cavitating?) but they took them off after discovering the damage the bow was taking from operating at those speeds.

>>29765984
Do you understand what fluid friction is?

>>29766056
>>29766071
You aren't the first guys to stumble over your own reading comprehension (or lack thereof). And you won't be the last.

This post: >>29759947 spawned this discussion. It's not like that anon didn't mean it literally. He really did as is evident from the statement he was referring to and what he said in reply.

>>29766018
>so where does the "displaced water go?
Up. At lower speeds it goes less up and more around. Equivalently to how at low subsonic speeds, (effectively incompressible) air rushes around a body but at transonic speeds it is more prone to compressing as the body passes through it.
>it's constrained by more, incompressible water, so the only place for it to go is up- hence the bigger bow wave.
Yes, but UNLIKE with air and the sound barrier and the Prandtl-Glauert singularity, there is no singularity at hull speed. There is no "wave barrier." Hull speed merely represents a point where wave-making drag begins to increase dramatically.

It's worth noting that, unlike with pressure/sound waves, gravity waves vary with wavelength; and the faster a displacement hull passes through the water, the longer the bow wave's wavelength becomes.

Don't you have a larger turning radius the faster you go? Also, how long does it take to stop a ship? Couple minutes?

>>29766102
Which is why it's streamline to reduce that but I'm not Bullshitting like I know the threshold of that

>>29766124
In what way is my "reading comprehension" lacking?

I allowed for the possible exceptions in this post -


>There are some very special hull forms which are the exception - generally when the beam is less than 6% of the water line length, but they wouldn't make good carriers, would they?

The topic of the thread, was why don't we build faster warships - and I explained why

>>29766205
>In what way is my "reading comprehension" lacking?
In regarding this hint: >>29766002 as hair splitting as it shows that you're apparently unaware of the prior discussion.

Just like cars are limited to approximately 220 mph because of wind resistance. After that going faster has exponentially higher energy requirements

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>>29768294
Aerodynamic drag begins to be the main source of energy consumption in cars already at speeds of about 70 km/h.