Surasdra, Saimese Torpedo Boat laid down 1935
Displacement:
330 t light; 343 t standard; 383 t normal; 415 t full load
Dimensions: Length overall / water x beam x draught
229.66 ft / 225.56 ft x 19.69 ft x 7.38 ft (normal load)
70.00 m / 68.75 m x 6.00 m x 2.25 m
Armament:
3 - 3.00" / 76.2 mm guns in single mounts, 13.23lbs / 6.00kg shells, 1935 Model
Dual purpose guns in deck mounts
on centreline ends, majority aft, 2 raised mounts - superfiring
6 - 0.98" / 25.0 mm guns (2x3 guns), 0.55lbs / 0.25kg shells, 1935 Model
Anti-aircraft guns in deck mounts
on side, all amidships
3 - 0.98" / 25.0 mm guns (1x3 guns), 0.55lbs / 0.25kg shells, 1935 Model
Anti-aircraft guns in deck mount
on centreline amidships
Weight of broadside 45 lbs / 20 kg
Shells per gun, main battery: 200
3 - 19.7" / 500 mm above water torpedoes
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.59" / 15 mm - -
2nd: 0.59" / 15 mm - -
3rd: 0.59" / 15 mm - -
Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 14,001 shp / 10,444 Kw = 30.71 kts
Range 2,000nm at 15.43 kts
Bunker at max displacement = 71 tons
Complement:
43 - 56
Cost:
£0.224 million / $0.895 million
Distribution of weights at normal displacement:
Armament: 6 tons, 1.5 %
Armour: 3 tons, 0.9 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.9 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 198 tons, 51.7 %
Hull, fittings & equipment: 120 tons, 31.4 %
Fuel, ammunition & stores: 53 tons, 13.8 %
Miscellaneous weights: 3 tons, 0.8 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
95 lbs / 43 Kg = 7.1 x 3.0 " / 76 mm shells or 0.1 torpedoes
Stability (Unstable if below 1.00): 1.16
Metacentric height 0.6 ft / 0.2 m
Roll period: 10.9 seconds
Steadiness - As gun platform (Average = 50 %): 52 %
- Recoil effect (Restricted arc if above 1.00): 0.20
Seaboat quality (Average = 1.00): 0.71
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.409
Length to Beam Ratio: 11.46 : 1
'Natural speed' for length: 15.02 kts
Power going to wave formation at top speed: 71 %
Trim (Max stability = 0, Max steadiness = 100): 73
Bow angle (Positive = bow angles forward): 13.40 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17.22 ft / 5.25 m
- Forecastle (20 %): 13.94 ft / 4.25 m
- Mid (35 %): 13.94 ft / 4.25 m (5.74 ft / 1.75 m aft of break)
- Quarterdeck (15 %): 5.74 ft / 1.75 m
- Stern: 6.56 ft / 2.00 m
- Average freeboard: 8.94 ft / 2.72 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 179.4 %
- Above water (accommodation/working, high = better): 54.9 %
Waterplane Area: 2,748 Square feet or 255 Square metres
Displacement factor (Displacement / loading): 45 %
Structure weight / hull surface area: 21 lbs/sq ft or 102 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.51
- Longitudinal: 1.98
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather
Thirteen units.