P-1 Class Patrol Boat
P-1 to P-10, laid down 1932
P-1, Persia Patrolboat laid down 1932
Displacement:
50 t light; 52 t standard; 56 t normal; 59 t full load
Dimensions: Length overall / water x beam x draught
72,39 ft / 72,18 ft x 11,48 ft x 5,91 ft (normal load)
22,07 m / 22,00 m x 3,50 m x 1,80 m
Armament:
1 - 2,95" / 75,0 mm guns in single mounts, 12,87lbs / 5,84kg shells, 1932 Model
Breech loading gun in deck mount
on centreline forward
2 - 0,98" / 25,0 mm guns (1x2 guns), 0,48lbs / 0,22kg shells, 1932 Model
Anti-aircraft guns in deck mount
on centreline aft
4 - 0,52" / 13,2 mm guns in single mounts, 0,07lbs / 0,03kg shells, 1932 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 14 lbs / 6 kg
Shells per gun, main battery: 75
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0,79" / 20 mm - -
2nd: 0,79" / 20 mm - -
Machinery:
Diesel Internal combustion motors,
Geared drive, 1 shaft, 714 shp / 532 Kw = 17,00 kts
Range 1 000nm at 11,00 kts
Bunker at max displacement = 7 tons
Complement:
9 - 13
Cost:
£0,028 million / $0,111 million
Distribution of weights at normal displacement:
Armament: 2 tons, 3,2 %
Armour: 1 tons, 2,5 %
- Belts: 0 tons, 0,0 %
- Torpedo bulkhead: 0 tons, 0,0 %
- Armament: 1 tons, 2,5 %
- Armour Deck: 0 tons, 0,0 %
- Conning Tower: 0 tons, 0,0 %
Machinery: 21 tons, 36,7 %
Hull, fittings & equipment: 27 tons, 47,9 %
Fuel, ammunition & stores: 5 tons, 9,7 %
Miscellaneous weights: 0 tons, 0,0 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
36 lbs / 17 Kg = 2,8 x 3,0 " / 75 mm shells or 0,1 torpedoes
Stability (Unstable if below 1.00): 1,00
Metacentric height 0,2 ft / 0,1 m
Roll period: 11,0 seconds
Steadiness - As gun platform (Average = 50 %): 67 %
- Recoil effect (Restricted arc if above 1.00): 0,62
Seaboat quality (Average = 1.00): 1,21
Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,400
Length to Beam Ratio: 6,29 : 1
'Natural speed' for length: 8,50 kts
Power going to wave formation at top speed: 76 %
Trim (Max stability = 0, Max steadiness = 100): 55
Bow angle (Positive = bow angles forward): 1,50 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 8,20 ft / 2,50 m
- Forecastle (20 %): 7,22 ft / 2,20 m
- Mid (50 %): 7,22 ft / 2,20 m
- Quarterdeck (15 %): 7,22 ft / 2,20 m
- Stern: 7,22 ft / 2,20 m
- Average freeboard: 7,30 ft / 2,22 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 141,9 %
- Above water (accommodation/working, high = better): 73,7 %
Waterplane Area: 482 Square feet or 45 Square metres
Displacement factor (Displacement / loading): 97 %
Structure weight / hull surface area: 17 lbs/sq ft or 83 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,65
- Longitudinal: 28,84
- Overall: 0,95
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Good seaboat, rides out heavy weather easily