MS-1 Minesweeper

Jeremy · January 23, 2025, 05:30:18 PM

MS-1, Laksmanavati Minesweeper, laid down 1908

Although primarily intended as minesweepers, the MS-1 class can also serve as submarine chasers or light minelayers. Seven ships were constructed (numbers MS-1 through MS-7) but all were scrapped by 1930 when the RLN finally eliminated all coal-fired ships from the active navy. Some ships received four 40/39 AA guns during refits in the early 1920s.

Displacement:
497 t light; 516 t standard; 583 t normal; 636 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(171.10 ft / 164.04 ft) x 25.26 ft x (9.84 / 10.52 ft)
(52.15 m / 50.00 m) x 7.70 m x (3.00 / 3.21 m)

Armament:
1 - 4.33" / 110 mm 45.0 cal gun - 40.96lbs / 18.58kg shells, 150 per gun
Quick firing gun in deck mount, 1908 Model
1 x Single mount on centreline, forward deck forward
4 - 1.57" / 40.0 mm 39.0 cal guns - 1.85lbs / 0.84kg shells, 900 per gun
Anti-air guns in deck mounts, 1920 Model
2 x Single mounts on sides, aft deck forward
1 x Twin mount on sides amidships
1 raised mount
4 - 0.47" / 12.0 mm 90.0 cal guns - 0.07lbs / 0.03kg shells, 2,000 per gun
Machine guns in deck mounts, 1908 Model
4 x Single mounts on sides, evenly spread
4 raised mounts
Weight of broadside 49 lbs / 22 kg

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.98" / 25 mm - -
2nd: 0.79" / 20 mm - -

Machinery:
Coal and oil fired boilers, steam turbines,
Direct drive, 2 shafts, 925 shp / 690 Kw = 13.97 kts
Range 3,000nm at 10.00 kts
Bunker at max displacement = 120 tons (75% coal)

Complement:
59 - 77

Cost:
£0.027 million / $0.108 million

Distribution of weights at normal displacement:
Armament: 9 tons, 1.6 %
- Guns: 9 tons, 1.6 %
Armour: 4 tons, 0.7 %
- Armament: 4 tons, 0.7 %
Machinery: 50 tons, 8.6 %
Hull, fittings & equipment: 308 tons, 52.9 %
Fuel, ammunition & stores: 86 tons, 14.7 %
Miscellaneous weights: 125 tons, 21.5 %
- On freeboard deck: 105 tons
- Above deck: 20 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
2,537 lbs / 1,151 Kg = 62.5 x 4.3 " / 110 mm shells or 1.9 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 0.8 ft / 0.2 m
Roll period: 12.2 seconds
Steadiness - As gun platform (Average = 50 %): 32 %
- Recoil effect (Restricted arc if above 1.00): 0.14
Seaboat quality (Average = 1.00): 1.28

Hull form characteristics:
Hull has a flush deck,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0.500 / 0.511
Length to Beam Ratio: 6.49 : 1
'Natural speed' for length: 12.81 kts
Power going to wave formation at top speed: 51 %
Trim (Max stability = 0, Max steadiness = 100): 16
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 3.94 ft / 1.20 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 17.72 ft / 5.40 m, 13.78 ft / 4.20 m
- Forward deck: 50.00 %, 13.78 ft / 4.20 m, 13.78 ft / 4.20 m
- Aft deck: 15.00 %, 13.78 ft / 4.20 m, 13.78 ft / 4.20 m
- Quarter deck: 15.00 %, 13.78 ft / 4.20 m, 13.78 ft / 4.20 m
- Average freeboard: 14.09 ft / 4.30 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 34.5 %
- Above water (accommodation/working, high = better): 122.8 %
Waterplane Area: 2,761 Square feet or 257 Square metres
Displacement factor (Displacement / loading): 230 %
Structure weight / hull surface area: 46 lbs/sq ft or 225 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.06
- Longitudinal: 18.99
- Overall: 1.42
Excellent machinery, storage, compartmentation space
Excellent accommodation and workspace room
Good seaboat, rides out heavy weather easily

Fittings:
-2 t: Fire control (1918) (above deck)
-1 t: Spotlight (above deck)
-25 t: Sweeping gear (on deck)
-60 t: Mines (on deck)
-10 t: 50x 90 kg DC (on deck)
-17 + 15 t: Weight reserve (above deck + on deck)

MS-1 Minesweeper

Jeremy