WesWorld

The Aurangabad class destroyers follow from the preceding Rawalpindi class with only a few minor adjustments:

-Slightly increased bunkerage
-A slightly heavier electronics fit
-The light AA armament is six twin 25mm, rather than ten singles.

Six units are to be built in 1947, plus two under contract for Hedjaz.


Enter ship name, Enter country Enter ship type laid down 1947

Displacement:
2,076 t light; 2,209 t standard; 2,546 t normal; 2,816 t full load

Dimensions: Length overall / water x beam x draught
390.74 ft / 379.10 ft x 42.65 ft x 13.12 ft (normal load)
119.10 m / 115.55 m x 13.00 m x 4.00 m

Armament:
6 - 4.92" / 125 mm guns (3x2 guns), 59.59lbs / 27.03kg shells, 1947 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority aft, 1 raised mount aft - superfiring
4 - 2.24" / 57.0 mm guns (2x2 guns), 5.65lbs / 2.56kg shells, 1947 Model
Dual purpose guns in deck mounts
on side, all amidships, all raised mounts - superfiring
2 - 2.24" / 57.0 mm guns (1x2 guns), 5.65lbs / 2.56kg shells, 1947 Model
Dual purpose guns in deck mount
on centreline forward, all raised guns - superfiring
12 - 0.98" / 25.0 mm guns (6x2 guns), 0.48lbs / 0.22kg shells, 1947 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 397 lbs / 180 kg
Shells per gun, main battery: 350
5 - 21.7" / 550 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.79" / 20 mm 1.97" / 50 mm
3rd: 0.98" / 25 mm 0.39" / 10 mm -
4th: 0.98" / 25 mm 0.39" / 10 mm -
5th: 0.39" / 10 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 48,258 shp / 36,000 Kw = 34.38 kts
Range 7,500nm at 15.00 kts
Bunker at max displacement = 608 tons

Complement:
178 - 232

Cost:
£1.959 million / $7.835 million

Distribution of weights at normal displacement:
Armament: 50 tons, 1.9 %
Armour: 30 tons, 1.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 30 tons, 1.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 1,107 tons, 43.5 %
Hull, fittings & equipment: 739 tons, 29.0 %
Fuel, ammunition & stores: 470 tons, 18.5 %
Miscellaneous weights: 151 tons, 5.9 %
-60 t: Radar, sonar, fire control, and other electronics
-31 t: Weight reserve
-20 t: Rails, throwers, and 60 depth charges
-20 t: Mangus ASW system and five reload salvoes (abaft "B" gun)
-10 t: Blast shielding around Mangus and deck reinforcement below
-10 t: Torpedo reloads and equipment

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
835 lbs / 379 Kg = 14.0 x 4.9 " / 125 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric height 1.9 ft / 0.6 m
Roll period: 12.9 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.35
Seaboat quality (Average = 1.00): 0.87

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.420
Length to Beam Ratio: 8.89 : 1
'Natural speed' for length: 22.68 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 69
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22.97 ft / 7.00 m
- Forecastle (20 %): 19.03 ft / 5.80 m
- Mid (50 %): 15.09 ft / 4.60 m
- Quarterdeck (15 %): 15.09 ft / 4.60 m
- Stern: 15.09 ft / 4.60 m
- Average freeboard: 16.78 ft / 5.12 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 163.8 %
- Above water (accommodation/working, high = better): 138.6 %
Waterplane Area: 10,465 Square feet or 972 Square metres
Displacement factor (Displacement / loading): 86 %
Structure weight / hull surface area: 41 lbs/sq ft or 198 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.68
- Overall: 0.56
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

The armament and speed is impressive; however, the seaworthiness of the design would concern me. Your mileage may vary, of course.

Considering its size, it is not going to be that much worse than a similar-sized destroyer with a seaboat rating of 1. I feel that with simming such small ships like destroyers and torpedo boats, we are too worried about the seaboat rating and try to keep it above 1 while it is probably totally acceptable to go as low as 0.70 like I did when I tried to sim the Shimakaze (which is at 0.72).

It was intended that the LSD Colonel Asaf Kripalani would undergo a couple of years of trials and operational evaluations before Bharat moved to build any other amphibs with a large well deck. That plan didn't even last untl the Kripalani's completion in 1946.

By then, Bharat had mobilized a major portion of its navy to react to the Balochi earthquake, saving thousands of lives using everything from aircraft carriers down to landing craft. While the operation proved the utility of naval vessels, there was also the realization that the navy had been stretched fairly thin by an event on its most sparsely populated coast. Another cyclone hitting Bengal would affect millions of people; more ships would be needed.

At the same time, the two-year guarantees of confidence supplied to the Sardesei government by some parties in the House of Representatives was coming to an end, and Sardesei recognized that he'd need to throw some bones to the more militant parties, if only to scare the militantly anti-militant parties a bit and ensure that, whatever the case, Sardesei could continue to lead the government.

Through it all, the Naval Infantry Brigade had been making the case that it needed new landing ships for amphibious assaults. The converted troopships it had were two decades old, and had been at best adequate for their roles even when new to service. They wanted newer, more capable ships to permit Bharati force projection ashore. Their initial attempt to acquire such a ship had been only partially successful with the Kripalani, which was too small to land a battalion of troops.

These differing interests came together in 1946. With a 1947 lay-down planned for the lead unit of a new class, designing from scratch was impractical. Instead, some of the larger designs prepared in advance of the Kripalani decision were examined, and one was selected after a few revisions were made.

The Subedar Yugi Talsania is named for a heroic junior officer killed in the 1857 rising against Great Britain. She can embark a naval infantry battalion, plus vehicles, plus cargo, plus landing craft. Other facilities include limited workshops for vehicle and small craft repair, working facilities for the naval infantry, and a well-equipped medical facility including two operating rooms. It's expected that additional temporary medical facilities could be set up in the vehicle deck if it were empty, but studies haven't progressed very far on this so far.

The well deck is larger and more optimized than that of the Kripalani. The aft 80 metres is 22 metres wide, while the forward 40 metres is 11 metres wide. This permits two possible configurations of landing craft: Either three LCT up the middle, with five LCM on either side, or four LCM forward and four LCT in two rows aft, either case also leaving a couple of metres for bumpers and open water. Four sets of davits are available to store LCMs amidships.

A simple helicopter pad, capable of accommodating one machine, has been hastily added over the well deck, but the ship is not intended to embark or operate such machines at this time.

Two units will be built in 1947-8, with expectations of a second pair in the early fifties.

TWO NOTES ON COSTING:

-->For the purpose of assigning landing craft weight to the LSD, the cargo capacity of the landing craft has been discounted. This cargo is already accounted for elsewhere in the ship as troops, cargo, or vehicles.

-->For the purpose of assigning cost to the LSD, the cost of landing craft has been discounted; these are being built separately in the Bharati budget.


Subedar Yugi Talsania, Bharati landing ship dock, laid down 1947

Displacement:
9,528 t light; 9,878 t standard; 14,529 t normal; 18,251 t full load

Dimensions: Length overall / water x beam x draught
529.91 ft / 524.93 ft x 98.43 ft x 16.40 ft (normal load)
161.52 m / 160.00 m x 30.00 m x 5.00 m

Armament:
4 - 4.92" / 125 mm guns (2x2 guns), 59.59lbs / 27.03kg shells, 1947 Model
Dual purpose guns in deck mounts with hoists
on centreline, all forward, 1 raised mount - superfiring
12 - 2.24" / 57.0 mm guns (6x2 guns), 5.65lbs / 2.56kg shells, 1947 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
16 - 0.98" / 25.0 mm guns (8x2 guns), 0.48lbs / 0.22kg shells, 1947 Model
Machine guns in deck mounts
on side, evenly spread
8 - 0.59" / 15.0 mm guns in single mounts, 0.10lbs / 0.05kg shells, 1947 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 315 lbs / 143 kg
Shells per gun, main battery: 300

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.79" / 20 mm 1.97" / 50 mm
2nd: 0.79" / 20 mm 0.39" / 10 mm -
3rd: 0.39" / 10 mm - -
4th: 0.39" / 10 mm - -

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 13,405 shp / 10,000 Kw = 18.36 kts
Range 9,200nm at 15,00 kts
Bunker at max displacement = 2,203 tons
(Simmed as Range 35,000nm at 15.00 kts
Bunker at max displacement = 8,373 tons)

Complement:
661 - 860

Cost:
£3.003 million / $12.011 million

Distribution of weights at normal displacement:
Armament: 39 tons, 0.3 %
Armour: 27 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 27 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 331 tons, 2.3 %
Hull, fittings & equipment: 4,740 tons, 32.6 %
Fuel, ammunition & stores: 5,001 tons, 34.4 %
Miscellaneous weights: 4,391 tons, 30.2 %
-5,280 t: 80x22x2.4m and 40x11x 2.4 m well deck (simmed as bunkerage)
-1,800 t: Accommodation for 900 naval infantry, vehicle crews, and passengers
-890 t: Low-slung cargo/fuel/supplies (simmed as bunkerage)
-870 t: Vehicle deck
-700 t: 3 LCT and 12 LCM (cargo capacity of these craft is discounted per costing notes)
-200 t: Working space for naval infantry
-200 t: Additional cranes
-100 t: Landing craft repair
-160 t: Davits for four LCM
-100 t: Medical facilities
-100 t: Vehicle repair facilities
-50 t: Helicopter pad (no embarkation facilities)
-91 t: Weight reserve

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
51,193 lbs / 23,221 Kg = 859.0 x 4.9 " / 125 mm shells or 6.6 torpedoes
Stability (Unstable if below 1.00): 1.48
Metacentric height 9.6 ft / 2.9 m
Roll period: 13.4 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.01
Seaboat quality (Average = 1.00): 1.71

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.600
Length to Beam Ratio: 5.33 : 1
'Natural speed' for length: 27.30 kts
Power going to wave formation at top speed: 38 %
Trim (Max stability = 0, Max steadiness = 100): 41
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 28.22 ft / 8.60 m
- Forecastle (20 %): 24.28 ft / 7.40 m
- Mid (50 %): 24.28 ft / 7.40 m (16.40 ft / 5.00 m aft of break)
- Quarterdeck (15 %): 16.40 ft / 5.00 m
- Stern: 16.40 ft / 5.00 m
- Average freeboard: 20.66 ft / 6.30 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 43.8 %
- Above water (accommodation/working, high = better): 227.4 %
Waterplane Area: 39,384 Square feet or 3,659 Square metres
Displacement factor (Displacement / loading): 269 %
Structure weight / hull surface area: 100 lbs/sq ft or 486 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.38
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Looks like a nice ship; I don't see anything to comment on other than its apparent suitability. :P

I'll never turn down a comment of that nature.

To me it looks a bit messy. As it is now, the 5280 tons of the well deck suggests it is part of the miscellaneous weights but you only have 4391 tons of those. There is no clear indication where all the ~6000 tons of fuel that is not part of the ship's actual bunkerage is used for except the "890 t: Low-slung cargo/fuel/supplies (simmed as bunkerage)". Also maybe I am doing something wrong but with 10,000 kW the speed I get is 17.771 knots and not 18.36 knots. Same is true for the range of 9,200nm at 15,00 kts. Those values roughly match that of a vessel with a draught of 3.75 meters, not 5 meters.

Edit: @#$% forgot to mark the transom stern box. Sorry about that.

Another thing is that removing the tonnage of the well deck only raises the ship by about 1.8 meters while I get the impression from such ships that the bottom of the well deck when empty should be above the waterline. Assuming it should be 30 cm above the waterline when the well deck is empty, adding the 5280 tons of water to the ship will only make the well deck about 1.5 meters deep and not 2.4 meters. I messed around a lot with the CAV design and that is the main reason I have the ballast tanks there. That way the ship can be lowered and raised enough so that the well deck has the proper depth when full and above the waterline when empty.

Quoted from "Rooijen10"

To me it looks a bit messy. As it is now, the 5280 tons of the well deck suggests it is part of the miscellaneous weights but you only have 4391 tons of those. There is no clear indication where all the ~6000 tons of fuel that is not part of the ship's actual bunkerage is used for except the "890 t: Low-slung cargo/fuel/supplies (simmed as bunkerage)". Also maybe I am doing something wrong but with 10,000 kW the speed I get is 17.771 knots and not 18.36 knots. Same is true for the range of 9,200nm at 15,00 kts. Those values roughly match that of a vessel with a draught of 3.75 meters, not 5 meters.

Edit: @#$% forgot to mark the transom stern box. Sorry about that.

I believe adding a "Simmed as bunkerage" comment after the well-deck tonnage has sufficed for this.

I always lay out all my "add-ons" and special weight allocations under "Miscellaneous Weight", even if it's not sourced from "Miscellaneous Weight", so I have all these things together in one place.

Quoted

Another thing is that removing the tonnage of the well deck only raises the ship by about 1.8 meters while I get the impression from such ships that the bottom of the well deck when empty should be above the waterline. Assuming it should be 30 cm above the waterline when the well deck is empty, adding the 5280 tons of water to the ship will only make the well deck about 1.5 meters deep and not 2.4 meters. I messed around a lot with the CAV design and that is the main reason I have the ballast tanks there. That way the ship can be lowered and raised enough so that the well deck has the proper depth when full and above the waterline when empty.

This well-deck thing is a bit of a puzzle for me, too; after all, none of our calculations account for the volume of the well deck occupied by the landing craft - which probably gets to be significant. Assuming you're right, 1.5 metres is still enough to float out an LCT. So I'm just going to go with "flooding historical well decks to historical water depths is good enough."

...and I'm not trying to be flippant or dismissive of your observations, Walter, believe me. But having modeled my previous LSD very tightly on the historical USS Ashland - while somehow still coming out with a light displacement almost 25% larger - this is clearly an area of SS ship design that is more art than science. We've got a convention in place for dealing with well decks - which I believe I'm following - and it'll have to do until we generate another.

Quoted

I believe adding a "Simmed as bunkerage" comment after the well-deck tonnage has sufficed for this.

The thing is the with the quick glance I gave it the first time, it did not come over like that. It came over as being part of the miscellaneous weights. With the second glance, I noticed that that would not be possible, given the amount of miscellaneous weights available.

Quoted

I always lay out all my "add-ons" and special weight allocations under "Miscellaneous Weight", even if it's not sourced from "Miscellaneous Weight", so I have all these things together in one place.

I prefer to keep that all below my sim and then clearly keep both the miscellaneous breakdown and the bunker breakdown separate.

Quoted

none of our calculations account for the volume of the well deck occupied by the landing craft - which probably gets to be significant.

Yes, that is something I noticed as well. Using your design as example, if you have a well deck with 5,280 t of water, once you put all those LCTs and LCMs in there, you would be left with 4580 tons of water in the well deck since the volume of those landing craft would have pushed those 700 tons out of the well deck. However more logical to me is that, considering that all those tonnages are included in the design, the actual volume of the well deck is 5980 tons and once the 700 tons of landing craft leave the ship, the 'void' they leave behind is filled with 700 tons of water from the outside untill those landing craft return and 'push' those 700 tons of water out of the ship again. Therefore everything inside the dock, both water and landing craft, should be included into the total volume of the well deck.

Quoted

But having modeled my previous LSD very tightly on the historical USS Ashland - while somehow still coming out with a light displacement almost 25% larger

I think there is one thing you are forgetting with your Colonel Asaf Kripalani design. At light displacement all your miscellaneous weights are still included, but I am pretty sure that in the real world the light displacement of the USS Ashland does not included the "Landing craft, vehicles, and cargo" and other such loose stuff that is included into the light displacement value of your Colonel Asaf Kripalani design. If you remove the 1300 tons for the "Landing craft, vehicles, and cargo", you'll end up with a light displacement for the Colonel Asaf Kripalani of 4005 tons which is actually 27 tons lighter than the light displacement value that wiki gives for the USS Ashland.

Quoted

We've got a convention in place for dealing with well decks - which I believe I'm following - and it'll have to do until we generate another.

The thing is that what Bruce pointed out to me back when I posted the original CAV design I posted and looking into is some more, we have something that works out the well decks themselves but not really something that would actually lower the ship enough to get the proper well deck depth for that amount of water.

While it is probably not a good example due to the significant depth of its well deck, the CAV design requires almost the same amount of water in ballast tanks as in the well deck itself (9800t vs 10200t) in order to lower the ship enough in the water to give me that 3 meter depth for the well deck. Now with the landing ships it is not necessary to go all the way to 3 meters, but in theory that depth allows the CAV to even take some of Japan's Ha-100 class submarine along instead of the landing craft.