GB-9 Class
These second-hand German patrol boats, laid down in 1935-6, were acquired in 1942. Their low cost and relatively low age, in combination with the effective design, were quite popular with Hedjazi officials.
GB-9 to GB-12 (ex-VP11 to VP14), laid down 1935, refitted 1944-5
GB-13-14 (ex-VP15 to VP16), laid down 1936
VP-11, German Patrol Boat laid down 1934
Displacement: 288 t light; 299 t standard; 337 t normal; 367 t full load
Dimensions: Length overall / water x beam x draught
180.45 ft / 180.45 ft x 18.04 ft x 6.89 ft (normal load) [55.00 m / 55.00 m x 5.50 m x 2.10 m]
Armament:
2 - 3.46" / 88.0 mm guns in single mounts, 20.79lbs / 9.43kg shells, 1934 Model Dual purpose guns in deck mounts on centreline ends, evenly spread, 1 raised mount
2 - 1.46" / 37.0 mm guns (1x2 guns), 1.55lbs / 0.70kg shells, 1929 Model Anti-aircraft guns in deck mount on centreline aft, all raised guns - superfiring
8 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1928 Model Machine guns in deck mounts on side, evenly spread, 4 raised mounts
Weight of broadside 47 lbs / 21 kg
Shells per gun, main battery: 150
Armour:
Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.79" / 20 mm - -
2nd: 0.79" / 20 mm - -
3rd: 0.39" / 10 mm - -
Conning tower: 1.18" / 30 mm
Machinery:
Diesel Internal combustion motors, Geared drive, 2 shafts, 5,598 shp / 4,176 Kw = 25.00 kts
Range 4,000nm at 12.00 kts
Bunker at max displacement = 68 tons
Complement: 39 - 51
Cost: £0.170 million / $0.680 million
Distribution of weights at normal displacement:
Armament: 6 tons, 1.7 %
Armour: 5 tons, 1.4 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 4 tons, 1.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 1 tons, 0.4 %
Machinery: 140 tons, 41.7 %
Hull, fittings & equipment: 117 tons, 34.7 %
Fuel, ammunition & stores: 49 tons, 14.5 %
Miscellaneous weights: 20 tons, 5.9 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship): 130 lbs / 59 Kg = 6.3 x 3.5 " / 88 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.14
Metacentric height 0.5 ft / 0.1 m
Roll period: 10.8 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.32
Seaboat quality (Average = 1.00): 1.50
Hull form characteristics:
Hull has raised forecastle and transom stern
Block coefficient: 0.525
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 15.29 kts
Power going to wave formation at top speed: 72 %
Trim (Max stability = 0, Max steadiness = 100): 40
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 20.51 ft / 6.25 m
- Forecastle (35 %): 19.69 ft / 6.00 m (8.20 ft / 2.50 m aft of break)
- Mid (50 %): 8.20 ft / 2.50 m
- Quarterdeck (15 %): 8.20 ft / 2.50 m
- Stern: 8.20 ft / 2.50 m
- Average freeboard: 12.34 ft / 3.76 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 154.7 %
- Above water (accommodation/working, high = better): 92.5 %
Waterplane Area: 2,310 Square feet or 215 Square metres
Displacement factor (Displacement / loading): 85 %
Structure weight / hull surface area: 17 lbs/sq ft or 84 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 9.26
- Overall: 0.67
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Good seaboat, rides out heavy weather easily
15 tons for hydrophones and sonar
10 tons for depth charges and rails