WesWorld

Just one design is planned for this year...so far.

The Miraj class destroyers, like the Ahmadabad class cruisers, have been designed for the specific purpose of escorting the Talwar class aircraft carriers. To this end, there have been several changes from the preceding Bhubaneshwar class destroyers.

The gun armament has been increased to six guns, concentrated in three dual-purpose mounts. This is one less mount than found in the Bhubaneshwar, which has freed up space for additional anti-aircraft weapons. An additional twin 35 mm is installed aft, and a second 15 mm quadruple mount has also been added.

The ASW fit includes the standard depth charge racks aft and four depth-charge throwers amidships. A non-publicized addition is the enlargement of the sonar dome to accommodate a second oscillator angled at thrity five degrees from the horizontal (versus the ten degrees offset of the primary oscillator). In theory, this second oscillator will be used during an attack run, where the steeper angle should allow for contacts to be maintained longer - leading to a more accurate attack.

Speed has decreased as a result of the heavier armament and, as importantly, the longer operating range. The additional bunkerage has been supplied so that carrier operations are not too inhibited by a need to refuel escorts.

A less dramatic change from the Bhubaneshwar class is the different hull form, with a long, sloping forecastle that levels out aft of the second funnel. This should keep the forecastle dry and allow for decent seakeeping, while not costing too much hull strength.

Six untis are planned for 1933, two more for 1934.

<a href="http://photobucket.com/" target="_blank"><img src="http://img.photobucket.com/albums/v20/sharpj/miraj.png" border="0" alt="Photobucket - Video and Image Hosting"></a>

Miraj, laid down 1933

Displacement:
1,586 t light; 1,678 t standard; 1,951 t normal; 2,170 t full load

Dimensions: Length overall / water x beam x draught
394.14 ft / 372.05 ft x 34.45 ft x 13.32 ft (normal load)
120.13 m / 113.40 m x 10.50 m x 4.06 m

Armament:
6 - 4.92" / 125 mm guns (3x2 guns), 59.59lbs / 27.03kg shells, 1933 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority aft, 1 raised mount aft - superfiring
8 - 1.38" / 35.0 mm guns (4x2 guns), 1.31lbs / 0.59kg shells, 1933 Model
Anti-aircraft guns in deck mounts with hoists
on side, evenly spread, all raised mounts
8 - 0.59" / 15.0 mm guns (2x4 guns), 0.10lbs / 0.05kg shells, 1933 Model
Machine guns in deck mounts
on side, all aft, all raised mounts - superfiring
Weight of broadside 369 lbs / 167 kg
Shells per gun, main battery: 250
8 - 21.7" / 550 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.79" / 20 mm 0.79" / 20 mm -
2nd: 0.79" / 20 mm - -
3rd: 0.39" / 10 mm - -

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 36,192 shp / 26,999 Kw = 33.49 kts
Range 10,000nm at 12.00 kts (Bunkerage = 492 tons)

Complement:
146 - 190

Cost:
£1.038 million / $4.151 million

Distribution of weights at normal displacement:
Armament: 46 tons, 2.4 %
Armour: 18 tons, 0.9 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 18 tons, 0.9 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 895 tons, 45.9 %
Hull, fittings & equipment: 570 tons, 29.2 %
Fuel, ammunition & stores: 365 tons, 18.7 %
Miscellaneous weights: 58 tons, 3.0 %
15 t: Sonar
-10 t: DC racks
-16 t: 4 DCT + charges
-17 t: Weight reserve

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
510 lbs / 231 Kg = 8.6 x 4.9 " / 125 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.14
Metacentric height 1.3 ft / 0.4 m
Roll period: 12.7 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.66
Seaboat quality (Average = 1.00): 1.01

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.400
Length to Beam Ratio: 10.80 : 1
'Natural speed' for length: 22.17 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 69
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 26.90 ft / 8.20 m
- Forecastle (20 %): 19.03 ft / 5.80 m
- Mid (50 %): 11.15 ft / 3.40 m
- Quarterdeck (15 %): 11.15 ft / 3.40 m
- Stern: 11.15 ft / 3.40 m
- Average freeboard: 14.54 ft / 4.43 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 170.6 %
- Above water (accommodation/working, high = better): 75.2 %
Waterplane Area: 8,187 Square feet or 761 Square metres
Displacement factor (Displacement / loading): 76 %
Structure weight / hull surface area: 36 lbs/sq ft or 176 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.59
- Overall: 0.56
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Ship has slow, easy roll, a good, steady gun platform

Nice drawing and good story, Doc.

I like her general layout but she´s indeed a bit slow for my liking.

Regarding the drawing one question popped up in my mind: Will her bridge crew be hampered by smoke? Her director and upper bridge is quite close to the first funnel. So I´d try to either angle the funnels or at least use a funnel cap....

You'd certainly want geared turbines rather than the direct drive she currently has.

I have to say that I'm not thrilled with the second sonar oscillator idea, that sounds like an idea that should come after discovering the difficulty of keeping track of a submarine during an attack run.

I think you'd be better off in going to a raised forecastle with the break by the fore funnel. At the moment I wouldn't want to be by the fore torpedo bank as the waves come sweeping down the deck towards me.

With Sonar angled down at 35° you'll start getting wierd effects. The return signal won't be a strong because of the stepper angle. You'll likely get more returns off the denser water below. Working in shallower water [probably up to 500-1000m ish] means returns off the bottom as well. Trying to process these different signals will be difficult. Another option - a larger pattern aft so the submarine will be hit even if it does move. Or drop 10tons of explosive off the stern resulting in a 138m kill radius...

Good range, and I like the parabolic sheer. Even if it is difficult to build, it is very graceful.

I'm not so convinced about the speed, but it probably is adequate if she's intended solely for the carrier escort mission. The only catch is, it probably restricts her utility as a destroyer for general fleet work. Again, the twinned sonars might present problems from a data-processing point of view, and might be premature, depending on India's experience with submarines.

I agree that the speed is not ideal; however, I have to fit my requirements into a Type B hull - or at least something I can pass off as one - since I can only build 9,600 t of Type A destroyers. I reckoned I could give up a half knot from the preceding class since anti-surface ops are not on the top of the list. It does limit their utility elsewhere, but that's life, I guess.

Funnel caps may be an idea. I'll contemplate it.

On the sonar: India has precisely as much experience in ASW as everybody else in the past fifteen years. It's a first crack at innovation that might be explained through training ops. Perhaps I'll scale it back to an experimental installation in one unit and see what happens.

Geared turbines? Okay, I'll make that change. That's one part of Springsharp I have yet to fully figure out, and the choice doesn't seemt to affect the sim. But I'll make the revision.

The type of engines makes no difference to the sim, agreed, at least not in this version of SS. But no one in their right mind would be using direct drive turbines in the 1930s when they could use geared turbines.

Quoted

Originally posted by The Rock Doctor
On the sonar: India has precisely as much experience in ASW as everybody else in the past fifteen years. It's a first crack at innovation that might be explained through training ops. Perhaps I'll scale it back to an experimental installation in one unit and see what happens.

Well, there are other navies that introduced (more advanced) technology without any life fire testing under war conditions. So it should be a problem to have a second sonar set on an Indian DD.

I think Red Admiral may be correct concerning the need to redsign your DD with a raised forecastle. The forward boats could be in for rough time of it also. Raising the forward gun to fire directly over the bow at zero elevation might be a good idea too.

The forefunnel is very close to the bridge and there may be some smoke problems. Raking the funnels or installing funnel-caps would be helpful and reducing the height of the aft funnel would compensate for the additional weight.

The power output is not much of a concern for me. Given the size of Miraj, she should be able to maintain speeds close to her maximum even in heavy seas.

Here's my take on Miraj:
<a href="http://photobucket.com/" target="_blank"><img src="http://img.photobucket.com/albums/v79/BCRenown/miraj-2.png" border="0" alt="Photobucket - Video and Image Hosting"></a>

Quoted

Originally posted by Hrolf Hakonson
You'd certainly want geared turbines rather than the direct drive she currently has.

I have to say that I'm not thrilled with the second sonar oscillator idea, that sounds like an idea that should come after discovering the difficulty of keeping track of a submarine during an attack run.

Perfectly reasonable to conclude after a Danish sub put one in Hyderabad during the Andaman Sea Crisis, right Rocky?

Now that you mention it, yeah...although I think it was a different cruiser.

But I thought that was the reason we came up with for H not having a bigger role in the fighting?

I checked the Andaman Sea thread - it was Cochin that was damaged, not Hyderabad.

Ok, i must be remembering our PM chats trying to build the story!

I wouldnt worry about the speed, after all they are 1/2 a knot faster than my own destroyers. It just depends on what your priorities are.