Hefring, Netherlands gunboat laid down 1940, launched 1940, completed
1941 (engine 1940)
Displacement:
1 060 t light;
1 135 t standard; 1 401 t normal; 1 613 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(280,26 ft / 273,29 ft)
x 36,42 ft x (10,83 / 11,99 ft)
(85,42 m / 83,30 m) x
11,10 m x (3,30 / 3,66 m)
Armament:
2 - 5,87" / 149 mm 50,0
cal guns - 102,96lbs / 46,70kg shells, 150 per gun
Quick firing guns in deck and hoist mounts,
1921 Model
2 x Single mounts on centreline ends, evenly
spread
2 - 4,13" / 105 mm 46,0
cal guns - 35,27lbs / 16,00kg shells, 250 per gun
Dual purpose guns in deck mount, 1931 Model
1 x Twin mount on centreline aft deck aft
1 raised
mount
6 - 1,57" / 40,0 mm
60,0 cal guns - 2,05lbs / 0,93kg shells, 2 500 per gun
Anti-air guns in deck mounts, 1937 Model
1 x Twin mount on centreline, forward deck
forward
1 raised
mount
2 x Twin mounts on sides, aft deck centre
2 raised mounts
6 - 0,79" / 20,0 mm
60,0 cal guns - 0,35lbs / 0,16kg shells, 3 000 per gun
Anti-air guns in deck mounts, 1938 Model
2 x Twin mounts on sides, aft deck centre
2 raised
mounts
2 x Single mounts on sides, forward deck
centre
2 double raised
mounts
Weight of broadside 286 lbs
/ 130 kg
Main DC/AS Mortars
2 - 396,83 lbs / 180,00 kg
Depth Charges + 36 reloads - 6,732 t total
in Stern depth charge
racks
2nd DC/AS Mortars
2 - 396,83 lbs / 180,00 kg
Depth Charges + 24 reloads - 4,606 t total
in Depth charge throwers
Armour:
- Belts: Width (max) Length
(avg) Height (avg)
Main: 1,57" / 40 mm 185,70 ft / 56,60 m 11,15
ft / 3,40 m
Ends: Unarmoured
Main Belt covers 105% of normal length
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist
(max)
Main: 1,57" / 40 mm - 0,98" / 25 mm
2nd: 0,51" / 13 mm -
-
- Armoured deck - single deck:
For and Aft decks:
0,98" / 25 mm
- Conning towers: Forward
0,98" / 25 mm, Aft 0,00" / 0 mm
Machinery:
Diesel Internal
combustion motors,
Geared drive, 2 shafts,
4 800 shp / 3 581 Kw = 19,54 kts
Range 12 500nm at
12,00 kts
Bunker normal = 266
tons, at max displacement = 478 tons
Complement:
113 - 148
Cost:
£0,495 million / $1,979
million
Distribution of weights at normal displacement:
Armament: 93 tons, 6,7%
- Guns: 79 tons, 5,6%
- Weapons: 14 tons, 1,0%
Armour: 247 tons, 17,6%
- Belts: 136 tons, 9,7%
- Armament: 10 tons, 0,7%
- Armour Deck: 98 tons, 7,0%
- Conning Tower: 3 tons, 0,2%
Machinery: 128 tons,
9,2%
Hull, fittings &
equipment: 591 tons, 42,2%
Fuel, ammunition &
stores: 341 tons, 24,4%
Miscellaneous weights:
0 tons, 0,0%
Overall survivability and seakeeping ability:
Survivability (Non-critical
penetrating hits needed to sink ship):
3 955 lbs / 1 793 Kg = 39,2 x 5,9 " /
149 mm shells or 1,3 torpedoes
Stability (Unstable if
below 1.00): 1,32
Metacentric height 1,8
ft / 0,6 m
Roll period: 11,4
seconds
Steadiness - As gun platform (Average = 50 %): 70 %
-
Recoil effect (Restricted arc if above 1.00): 0,40
Seaboat quality (Average = 1.00): 2,00
Hull form characteristics:
Hull has a flush deck,
a normal bow and a round stern
Block coefficient
(normal/deep): 0,455 / 0,473
Length to Beam Ratio:
7,50 : 1
'Natural speed' for
length: 16,53 kts
Power going to wave
formation at top speed: 51 %
Trim (Max stability =
0, Max steadiness = 100): 35
Bow angle (Positive =
bow angles forward): 18,00 degrees
Stern overhang: 1,64 ft
/ 0,50 m
Freeboard (% = length
of deck as a percentage of waterline length):
Fore
end, Aft end
- Forecastle: 20,00%, 16,40 ft /
5,00 m, 14,11 ft / 4,30 m
- Forward deck: 34,00%, 14,11 ft / 4,30
m, 14,11 ft / 4,30 m
- Aft deck: 34,00%, 14,11 ft / 4,30 m, 14,11 ft / 4,30 m
- Quarter deck: 12,00%, 14,11 ft /
4,30 m, 14,11 ft / 4,30 m
- Average freeboard: 14,29 ft / 4,36 m
Ship tends to be wet
forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low =
better): 50,8%
- Above
water (accommodation/working, high = better): 151,6%
Waterplane Area:
6 375 Square feet or 592 Square metres
Displacement factor
(Displacement / loading): 183%
Structure weight / hull
surface area: 57 lbs/sq ft or 277 Kg/sq metre
Hull strength
(Relative):
-
Cross-sectional: 0,88
-
Longitudinal: 3,85
- Overall:
1,02
Excellent machinery,
storage, compartmentation space
Excellent accommodation
and workspace room
Ship has slow, easy
roll, a good, steady gun platform
Excellent seaboat,
comfortable, can fire her guns in the heaviest weather
Hefring (1941)
Ulfr (1941)