6
   

The Ironclads

 
 
edgarblythe
 
  1  
Reply Tue 10 Jan, 2017 01:51 pm
The destroyer I was on had five inch guns on the front and three inchers on the back. During my hitch the three inch ones were done away with, as the ship was upgraded, eventually acquiring nuclear missile capability. I was told that research was advancing so rapidly that by the time a new system could be installed newer more advanced systems already were available.
Walter Hinteler
 
  2  
Reply Tue 10 Jan, 2017 02:19 pm
@edgarblythe,
I've always liked the Fletcher-class destroyers as being elegant ships. (The crews in our navy were quite the opposite)

We had only a 40 mm Bofors gun on the minesweeper. But the wooden planks on the bow moved quite a bit up and down during shooting periods ... not speak of other parts more "downstairs" (Teak, mahagoni and oak were on more than just stress tests Wink )
0 Replies
 
georgeob1
 
  1  
Reply Tue 10 Jan, 2017 02:24 pm
@centrox,
centrox wrote:

farmerman wrote:
deGauss the metal so didnt set off the ammo by static charges.

Er... that was so that the ships didn't set off floating mines sensitive to the change in the Earth's magnetic field caused by an untreated ship's hull


Actually they served both purposes. With the advent of magnetically activated delayed action fuses for general purpose aircraft low drag bombs in the late 1960s, this did become a problem for aircraft carriers and added degaussing cables were installed for selected hangar and flight deck areas of our carriers.
0 Replies
 
edgarblythe
 
  1  
Reply Tue 10 Jan, 2017 03:37 pm
http://blog.uspatriottactical.com/wp-content/uploads/USS-Zumwalt-612x324.jpg
http://blog.uspatriottactical.com/are-the-ironclad-ships-making-a-comeback/
georgeob1
 
  1  
Reply Tue 10 Jan, 2017 04:30 pm
@edgarblythe,
I wonder what it's seakeeping qualities are like. An inward sloping freeboard and sharp prow are the exact opposite of what is needed for hydrodynamic stability. Stealthy aircraft have that problem too, but it is overcome with computer augmentted stability via the flight controls. Hard to do with a ship in the water.
edgarblythe
 
  1  
Reply Tue 10 Jan, 2017 04:39 pm
From my link:
Of course, the program to develop these ships has stirred a lot of controversy. As with many modern weapon systems that are being developed, they have experienced huge cost overruns that have resulted in changes to the initial numbers of them that were planned to be developed. Originally 31 of the Zumwalt Class Destroyers were scheduled to be built, but that has been scaled down to a mere 10 vessels now. That puts the cost of each ship at around 4 billion dollars apiece. That figure jeopardizes even reducing the number of planned ships down to the one that was christened at the iron works and two others that are currently under construction.

It will be interesting to see just how many of these technological marvels the Navy will actually produce in the upcoming few years.

farmerman
 
  1  
Reply Tue 10 Jan, 2017 05:38 pm
@edgarblythe,
have they screwed the number of nuke subs down from the 65 thqt were itemized among the fleets
0 Replies
 
farmerman
 
  1  
Reply Tue 10 Jan, 2017 05:43 pm
@georgeob1,
I remember the radical "balloon nose" chosen for the new subs. They became an asset for underwater speed. Do you think these Zumwalts have something in their designs that assist in the (square of the wetted- length rule). My only experience has been with piloting my little lobster boat. I tried racing it against some Deal Island trawlers with thinner, longer wetted surfaces qnd they just left me in their wakes. They would basically "Surf" on their own bow waves.

farmerman
 
  1  
Reply Tue 10 Jan, 2017 05:47 pm
@farmerman,
I have no idea what a "tumblehome" prow has to offer beyond stealth. Seems interesting that these hulls were in use on French Battleships during the Franco-Prussian War
georgeob1
 
  1  
Reply Tue 10 Jan, 2017 06:12 pm
@farmerman,
I think that's the only benefit. A overhanging prow adds to the ship's stability in pitch. Why theey were fashionable around 1900 has always been a mystery to me (perhaps the designers were thinking of Athenian rams).
0 Replies
 
georgeob1
 
  1  
Reply Tue 10 Jan, 2017 06:23 pm
@farmerman,
Over the last 15 years most surface ships have incorporated a bulbous bow protrusion just below the waterline. It significantly reduces the underwater hydrodynamic drag. Conversely a sharp prow at the surface interface reduces the wave drag. It took a little art to optimize the two simultaneously.

The so called wave (differential) equation governs (with suitable coefficients & parameters) both supersonic flow around an airfoil and the waves at the air water interface for a moving vehicle or ship. For many years engineers used shallow flows with vertically immersed airfoils to map the Mach waves based on the geometry of the bow waves in the water table.
farmerman
 
  1  
Reply Tue 10 Jan, 2017 10:34 pm
@georgeob1,
I guess warships dont use any of the "Pod" type thrusters that theyve been incorporating on passenger and container ships?
You mean they mapped it in Darcy Flow? Wink

farmerman
 
  1  
Reply Tue 10 Jan, 2017 10:45 pm
@georgeob1,
I did some more searching on those old ships with the "Zumwalt" bow and it read that the Russian ships were quite prone to leakage. I guess metallurgy and sheet metal work has improved a whole lot since then. (I assume they dont use glas hulls over steel in smaller navy boats (like Destroyers or DE's (Do they even have DE's any more? ?).


georgeob1
 
  1  
Reply Fri 13 Jan, 2017 09:49 am
@farmerman,
Nope. That's a geologist's view of hydrodynamics ( though in the perverse way of geologists, Darcy was somewhat ahead of his peers).

In a subsonic fluid flow drag is minimized by streamlining the back end of a moving body, while a suitably rounded, blunt front end is best. In a superxonic flow the situation is reversed: a sharp leading edge is required and the shap of the back end has little influence on the outcome.

For surface ships travelling (at subsonic speed) at the interface of two fluid mediums, there is an added factor involving the ship's effects on that fluid medium interface. It, like supersonic flow, is descrtibed by a suitably parameterized version of the Wave Equation.

goddam geologists !
georgeob1
 
  1  
Reply Fri 13 Jan, 2017 10:06 am
@farmerman,
farmerman wrote:

I did some more searching on those old ships with the "Zumwalt" bow and it read that the Russian ships were quite prone to leakage. I guess metallurgy and sheet metal work has improved a whole lot since then. (I assume they dont use glas hulls over steel in smaller navy boats (like Destroyers or DE's (Do they even have DE's any more? ?).


DEs were mosly low cost escorts for protection of convoys from submarines. ( I think the Brits called theirs "Corvettes" ). The nomenclature for naval ships changes over time ( the term "cruiser" , originally applied to a well armed, long-range ship that could operate independently , has virtually disappeared.)

I'm not sure what time period you had in mind in your reference to Russian ships. Many of the USSR's ships in the 1970s & 1980s appeared well designed, incorporating very innovative features, and letal (looking, at lest) weaponry. Their large surface ships bristled with weaponry; they had deep diving very fast submarines and advanced torpedo technology, However, as we began to learn in the 1980s ( through submarine taps on underwater cables in the White and Okhotsk Seas) none of it worked very well or was reliably maintained.
farmerman
 
  1  
Reply Fri 13 Jan, 2017 10:11 am
@georgeob1,
I always got ll workd up with laminar flow. I like being relaxed in my life, So all my fluids move in a Darcy mode.

It was my research team that developed a first model applying soil carbon content to contaminant sorption kinetics at darcy flows . We got a medal for what seemed to me to be "common sense"

farmerman
 
  1  
Reply Fri 13 Jan, 2017 10:13 am
@georgeob1,
The ""Zumwalt " style prows of Russian ships were back in the pre WWI era
georgeob1
 
  1  
Reply Fri 13 Jan, 2017 10:27 am
@farmerman,
OK. That makes sense. In that era the Russian economy was, by a wide margin, the fastest growing economy in Europe. They were building railroads and manufacturing infrastructure at a very rapid pace. ( another element of the tragedy of WWI).

Russia started a massive Naval buildup early in Nicholas II s reign, and did yet another after their disastrous losses in the 1905 war with Japan. During this period they added substantially to their own ship construction, but throughout the period depended a lot on ships manufactured in the UK and Germany under contract.

I'm not aware of any particularly Russian problems in this area, but they may well have existed. Ships hulls were then made of riveted sheet steel. and the seams were inherently leaky. Moreover steel fabrication and heat treatment were still a bit immature and problems with brittleness and crack propagation were fairly common. All that changed fairly quickly in the years after WWI.
0 Replies
 
Walter Hinteler
 
  1  
Reply Fri 13 Jan, 2017 10:42 am
@farmerman,
The Austro-Hungarian navy had similar dreadnought battleships: the Tegetthoff class.
0 Replies
 
panzade
 
  1  
Reply Fri 13 Jan, 2017 10:52 am
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0 Replies
 
 

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