Shipbucket

Is that suppose to upset me? lol@u.

A turbine is only as efficient as it's boiler. Thermodynamics.

http://en.wikipedia.org/wiki/BM-40A_reactor

"The BM-40A reactor is the nuclear fission reactor used to power four of the seven boats of the Soviet Navy's Project 705 Лира (Lira or Alfa in NATO designation) fourth generation submarines. It is a liquid metal cooled reactor (LMR), using highly enriched uranium-235 fuel to produce 155 MWt of power."

Produce 155 MWt of power. I'm aware it's megawatt thermal, Tim. What do you think it's using to create steam in the first place? That's right. Heat. Duh. But oh that's right, you were just trying to get one up on me. And failed miserably. :: plays the world's smallest violin ::

Enjoy the serenade.

Since we can't really specify that exact efficiency, it's just easiest to dictate a specific output.

The Alfa class had a turbine rated at 40,000 hp connected to the shaft. That's 30 MW right there. Only reason you wouldn't use a high power turbine is because they probably didn't want it going faster (design limits) or didn't have enough space for a bigger turbine. Either way, even if you tried to maintain your argument, the ship is a lot bigger than the sub, thus you'd add another reactor if need be. But of course there's a problem with your cherry picking argument there which I detail below.

Of course, the Sierra class doesn't list it as MWt (megawatt thermal). Simply lists 190 MW. The Akula II class's OK-650 is the same way. With the Alfa classes 155 MWt, it's hard to discern the intrinsic losses in the system, so even you don't have a single clue as to what it's actual power output is since it wasn't stated and we don't know the listed efficiency for the plant setup.

For example, the Embalse Nuclear Plant produces 2,109 MW of thermal power, and of that, 648 MW of electricity. That's 30% efficiency. Construction began in 1974, so it's pretty close to the era of the ship. But of course, naval nuke plants tend to be a little less efficient. But overall, every setup is different. And also, that's a pressurized heavy water reactor. Liquid metal plants have higher energy densities and are lighter and smaller in size overall. Rather than bother with all that, it's ten times easier to say 180 MW and be done with it. Another problem with your statement, is that reactors don't tend to be huge. Most have a fuel load the size of a baseball. You don't need a huge reactor to house a lot of power. The cooling systems tend to take up all the space.

http://en.wikipedia.org/wiki/OK-650_reactor

So Tim, I suppose I'd simply reply with...what do you want me to do? I could specify more reactors, but that doesn't get us anywhere. We could say, alright, let's set it at 30% efficiency, and figure something from there. But that's a huge pain in the ass and requires a lot of assumptions. So I did it the easy way, and stated the desired electrical/hp output from the reactor and turbine setup. And the idea that you can't generate 180 MW on an 8,000 ton ship is downright silly.

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sit here and laugh, but will not say anything. For I will surely get that hat fits of admin.

greetings
a naval architect student

as our teacher says: "When you think that everything between heaven and earth is possible, then you are the best in the engineering profession!" but then he is a bit odd. a bit like: "Back to the Future" movie

You don't have the displacement add things willy-nilly, especially when you don't have guidance radars for your SAMs (your SAMs by themselves mass over 240 metric tons). This is a really interesting point - The only US Ships to use more displacement for SAMs were the double ended Cruisers and Frigates* (Long Beach, Albany, Leahy, and Bainbridge Classes). Both nuclear power ships in the above list displaced more than your ship.

*Discounting the Carriers Kitty Hawk, Constellation, and America as didn't carry enough terriers to count, heck technically the Leahy and Bainbridge classes don't either.
We can however calculate a rough efficiency of the system. The Reactor outputs 155MWt, while the turbine outputs 30MW. 30/155 is about .19. This is a far cry for your .79 .

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𝐌𝐀𝐓𝐇𝐍𝐄𝐓- 𝑻𝒐 𝑪𝒐𝒈𝒊𝒕𝒂𝒕𝒆 𝒂𝒏𝒅 𝒕𝒐 𝑺𝒐𝒍𝒗𝒆

That doesn't tell us anything. We don't know if it's using all of that just for the propulsion. We also don't know if they maxed the system out, or only used what was needed for the desired speed.

And lastly, we're not even close to home. Because even using a rough efficiency doesn't give us the required weights for the reactor/s or the size of it or it's cooling systems. I'm figuring all the weights into Springsharp. Including the SAM's. 250 tons is chump change with this particular ship.

And as I said, I wasn't calculating it at 79%. I simply indicated a reactor setup that produces 180 MW of power usable for propulsion and grid needs. So technically it wasn't 79% at all. It was 100%. It's just that only 79% went to propulsion. The rest went to grid. It's a lot easier than trying to build a graph using the Carnot cycle, and then somehow try and figure out the weight and size of the reactor. If you want to do that, by all means go ahead.

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"All your base are belong to us"

It'll take about 600 MWt to produce 180 MW.

Using the Alfa class as our basis (since it used a liquid metal reactor as well), this equates out to about 3.8 times the output of the Alfa class. Since the ship in question is 3.5 times the tonnage of the Alfa class, and far larger size wise, it shouldn't be too much of a problem. Of course we still don't know the weights and sizes involved. We just have to assume that if it could fit in the Alfa class, it'll fit in the CLN.

Interesting tidbit. The reactor compartment of the D2G reactors were 1,200 tons. So 2,400 tons altogether. The A4W reactor used on the Nimitz was based off a 1960s design intended to replace the typical two reactor 60,000 SHP D2G plants found in DLGNs/CGNs with a single reactor. So we can assume that it may weigh around 2,400 tons. But of course it has higher energy density than the D2G, so it probably weighs less. But who knows. The Navy doesn't give info like that out.

Either way, my design is budgeted for 3,900 tons total propulsion weight, and 750 + 143 t for additional armaments or fuel and misc crap. That's why I said 250 tons for the SAM's (along with 120 t for AShM) is chump change. I tend to over-design in order to allow leeway room for error.

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"All your base are belong to us"

Springsharp doesn't calculate the technology curve beyond 1950. So really, the situation is much better than listed simply because technology would have come a long way in thirty years. I made it a couple hundred tons heavier overall.

Alagalagos Class CLN,

Displacement:
8,559 t light; 8,734 t standard; 8,778 t normal; 8,813 t full load

Dimensions: Length overall / water x beam x draught
570.12 ft / 545.00 ft x 66.60 ft x 20.90 ft (normal load)
173.77 m / 166.12 m x 20.30 m x 6.37 m

Machinery:
x? Lead-Bismuth cooled fast reactors @ 180 MW rated output, steam turbines,
geared drive, 4 shafts, 163,088 shp / 121,664 Kw = 40.00 kts
Range unlimited at 30.00 kts
Bunker at max displacement = 79 tons

Complement:
453 - 589

Cost:
£6.612 million / $26.450 million

Distribution of weights at normal displacement:
Armament: 0 tons, 0.0 %
Machinery: 3,902 tons, 44.4 %
Hull, fittings & equipment: 3,907 tons, 44.5 %
Fuel, ammunition & stores: 219 tons, 2.5 %
Miscellaneous weights: 750 tons, 8.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
6,057 lbs / 2,747 Kg = 56.1 x 6 " / 152 mm shells or 1.0 torpedoes
Stability (Unstable if below 1.00): 1.21
Metacentric height 3.8 ft / 1.2 m
Roll period: 14.3 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 1.00

Hull form characteristics:
Hull has raised forecastle, rise forward of midbreak, low quarterdeck
and transom stern
Block coefficient: 0.405
Length to Beam Ratio: 8.18 : 1
'Natural speed' for length: 27.46 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): -57.00 degrees
Stern overhang: 25.12 ft / 7.66 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 29.68 ft / 9.05 m
- Forecastle (20 %): 28.28 ft / 8.62 m (27.28 ft / 8.31 m aft of break)
- Mid (50 %): 25.28 ft / 7.71 m (25.15 ft / 7.67 m aft of break)
- Quarterdeck (15 %): 25.12 ft / 7.66 m (25.15 ft / 7.67 m before break)
- Stern: 25.15 ft / 7.67 m
- Average freeboard: 26.22 ft / 7.99 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 153.1 %
- Above water (accommodation/working, high = better): 251.0 %
Waterplane Area: 23,257 Square feet or 2,161 Square metres
Displacement factor (Displacement / loading): 103 %
Structure weight / hull surface area: 96 lbs/sq ft or 469 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.87
- Longitudinal: 3.43
- Overall: 1.00
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent

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"All your base are belong to us"

This is an innapropriate response to advice from a Moderator; and also, erik_t was (in moving this post) doing what I and any member of the admin team would have done. I have already warned you unofficially, so in fairness this is now an official warning. If I see anything else like the above I will ban you for a month.

I'll apologize.

Sorry for the disturbance.

But telling me to delete my post/thread and go read a book wasn't very nice.

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"All your base are belong to us"

Apology accepted

Just to interject, "taddah!"



Not probably going to much with it, any one is welcome to "fix" it in anyway foreseeable way (oh and thanks Gollevainen for the Russian missiles and Gun!)

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Miscellaneous|Victorian Colonial Navy|Murray Riverboats|Colony of Victoria AU|Project Sail-fixing SB's sail shortage
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"Loitering on the High Seas" (Named after the good ship Rodondo)
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