Slightly larger versions of the previous
Bumroong Boonyuen class with more reliable diesels, primitive hydrophones based on Dutch designs and 3 depth charge rails (2 drop off the beams aft the lifeboats and 1 off the stern) with 45 depth charges.
Ko Phuket, Siamese Patrol Boat laid down 1936
Displacement:
350 t light; 369 t standard; 414 t normal; 450 t full load
Dimensions: Length overall / water x beam x draught
183.72 ft / 173.88 ft x 24.61 ft x 8.20 ft (normal load)
56.00 m / 53.00 m x 7.50 m x 2.50 m
Armament:
2 - 3.94" / 100 mm guns in single mounts, 33.07lbs / 15.00kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.65lbs / 0.75kg shells, 1936 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread, 1 raised mount
6 - 0.51" / 13.0 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1936 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 73 lbs / 33 kg
Shells per gun, main battery: 250
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.57" / 40 mm - 1.57" / 40 mm
2nd: 0.98" / 25 mm - -
- Conning tower: 1.57" / 40 mm
Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 3,000 shp / 2,238 Kw = 20.05 kts
Range 4,000nm at 12.00 kts
Bunker at max displacement = 81 tons
Complement:
45 - 59
Cost:
£0.164 million / $0.656 million
Distribution of weights at normal displacement:
Armament: 8 tons, 2.0 %
Armour: 11 tons, 2.7 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 9 tons, 2.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.5 %
Machinery: 84 tons, 20.3 %
Hull, fittings & equipment: 214 tons, 51.7 %
Fuel, ammunition & stores: 64 tons, 15.6 %
Miscellaneous weights: 32 tons, 7.7 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
740 lbs / 336 Kg = 24.3 x 3.9 " / 100 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 0.8 ft / 0.2 m
Roll period: 11.8 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.39
Seaboat quality (Average = 1.00): 1.67
Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.413
Length to Beam Ratio: 7.07 : 1
'Natural speed' for length: 13.19 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 30
Bow angle (Positive = bow angles forward): 17.50 degrees
Stern overhang: 4.92 ft / 1.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 15.58 ft / 4.75 m
- Forecastle (20 %): 12.30 ft / 3.75 m
- Mid (50 %): 11.48 ft / 3.50 m
- Quarterdeck (15 %): 10.66 ft / 3.25 m
- Stern: 9.84 ft / 3.00 m
- Average freeboard: 11.70 ft / 3.57 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 91.9 %
- Above water (accommodation/working, high = better): 128.7 %
Waterplane Area: 2,655 Square feet or 247 Square metres
Displacement factor (Displacement / loading): 148 %
Structure weight / hull surface area: 38 lbs/sq ft or 185 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.79
- Longitudinal: 8.45
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Excellent seaboat, comfortable, can fire her guns in the heaviest weather
32t - Misc. Weight
-------------------------
15t - Hydrophone array
15t - Depth charges
2t - (empty)
Laid Down JAN 36
Ko Phuket
Ko Chang
Ko Pha Ngan
Ko Tarutao