WesWorld

Here's a possible design for a destroyer that could be the standard for future Indian destroyer construction - though I'd probably go to quad torpedo mounts and more light guns in later runs. The 4.9" (125mm) gun is a new model; gun layout is similar to a Fletcher, but with the 1.4" guns in the "X" position.

Speed seems low, but the powerplant gives about four knots less speed than similar historical ships were getting from theirs. I can't top 33 kts without getting a hull failure warning - which seems odd since both hull strength values remain above .5.

Thoughts?


G-131, laid down 1921

Length, 345 ft x Beam, 34.0 ft x Depth, 10.5 ft
1408 tons normal displacement (1301 tons standard)

Main battery: 4 x 4.9-inch
Secondary battery: 2 x 1.4-inch
AA battery: 4 x 0.6-inch

Weight of broadside: 238 lbs

6 TT, 19.7"

Hull unarmored

Battery armor:
Main, 2.0" shields / secondary, 1.0" shields
AA, 1.0" shields

Maximum speed for 34017 shp = 32.89 knots
Approximate cruising radius, 4000 nm / 12 kts

Typical complement: 115-149


Estimated cost, $1.768 million (£442,000)

Remarks:

Caution: Hull structure is subject to strain in open-sea
conditions.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 30 tons = 2 pct
Armor, total ..................... 14 tons = 1 pct

Armament 14 tons = 1 pct

Machinery ........................ 748 tons = 53 pct
Hull and fittings; equipment ..... 431 tons = 31 pct
Fuel, ammunition, stores ......... 155 tons = 11 pct
Miscellaneous weights ............ 30 tons = 2 pct
-----
1408 tons = 100 pct

Estimated metacentric height, 1.6 ft

Displacement summary:

Light ship: 1253 tons
Standard displacement: 1301 tons
Normal service: 1408 tons
Full load: 1487 tons

Loading submergence 181 tons/foot

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.31

Shellfire needed to sink: 359 lbs = 6.1 x 4.9-inch shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.3
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 62 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.21

Relative quality as a seaboat: 1.03

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.40
Sharpness coefficient: 0.29
Hull speed coefficient 'M' = 9.41
'Natural speed' for length = 18.6 knots
Power going to wave formation
at top speed: 66 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 190 percent

Relative accommodation and working space: 107 percent


Displacement factor: 54 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.52
(Structure weight per square
foot of hull surface: 36 lbs)

Relative longitudinal hull strength: 1.24
(for 14.4 ft average freeboard;
freeboard adjustment +4.2 ft)

Relative composite hull strength: 0.56

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

345.00 x 34.00 x 10.50; 14.40 -- Dimensions
0.40 -- Block coefficient
1921 -- Year laid down
32.89 / 4000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
30 tons -- Miscellaneous weights
++++++++++
4 x 4.90; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
2 x 1.40; 0 -- Secondary battery; turrets
Gun-shields
:
4 x 0.60 -- Tertiary (QF/AA) battery
Gun-shields
:
0 -- No fourth (light) battery
6 / 0 / 19.70 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
2.00 / 1.00 / 1.00 / 0.00 -- Battery armor


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

Hello the doctor:

I think the speed prob is due to the fact that historically speeds were given at light or standard displacement whereas SS calculates the speed at "normal" displacement.

to get the speed at standard reduce our draught until your "normal" = your "standard" displacement and readjust hp to your old figure (or rather 40% higher for trials conditions).

this is how I do mine ....

cheers

Bernhard