WesWorld

A RSwN gun boat for coastal patrols, fishery patrols and border enforcement

Kanonbåten, Sweden gunboat laid down 1892
Armoured gunboat

Displacement:
1 577 t light; 1 670 t standard; 1 700 t normal; 1 717 t full load
Loading submergence 228 tons/feet

Dimensions:
246,06 ft x 39,37 ft x 8,20 ft (normal load)
75,00 m x 12,00 m x 2,50 m

Armament:
1 - 8,27" / 210 mm guns
Caution: Main guns limited to end-on fire
4 - 6,00" / 152 mm guns
8 - 0,79" / 20 mm QF guns
Weight of broadside 717 lbs / 325 kg

Armour:
Belt 4,00" / 102 mm, upper belt 3,00" / 76 mm, end belts 2,00" / 51 mm
Belts cover 100 % of normal area
Main belt does not fully protect magazines and engineering spaces
Main gun shields 4,00" / 102 mm, 2nd gun shields 2,00" / 51 mm
QF gun shields 0,50" / 13 mm
Armour deck 1,00" / 25 mm, Conning tower 4,00" / 102 mm

Machinery:
Coal fired boilers, simple reciprocating steam engines,
Direct drive, 3 shafts, 3 045 ihp / 2 271 Kw = 16,00 kts
Range 800nm at 8,00 kts

Complement:
132 - 172

Cost:
£0,193 million / $0,770 million

Distribution of weights at normal displacement:
Armament: 90 tons, 5,3 %
Armour: 646 tons, 38,0 %
Belts: 423 tons, 24,9 %, Armament: 63 tons, 3,7 %, Armour Deck: 148 tons, 8,7 %
Conning Tower: 12 tons, 0,7 %, Torpedo bulkhead: 0 tons, 0,0 %
Machinery: 444 tons, 26,1 %
Hull, fittings & equipment: 372 tons, 21,9 %
Fuel, ammunition & stores: 123 tons, 7,3 %
Miscellaneous weights: 25 tons, 1,5 %

Metacentric height 1,4

Remarks:
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage & compartmentation is cramped
Room for accommodation & workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1,06
Shellfire needed to sink: 646 lbs / 293 Kg = 2,3 x 8,3 " / 210 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 0,5
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 93 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0,41
Relative quality as seaboat: 1,09

Hull form characteristics:
Block coefficient: 0,749
Sharpness coefficient: 0,47
Hull speed coefficient 'M': 6,30
'Natural speed' for length: 15,69 kts
Power going to wave formation at top speed: 51 %
Trim: 85
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 126,7 %
Relative accommodation and working space: 113,3 %
(Average = 100%)
Displacement factor: 67 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0,49
(Structure weight / hull surface area: 35 lbs / square foot or 173 Kg / square metre)
Relative longitudinal hull strength: 0,70
(for 9,84 ft / 3,00 m average freeboard, freeboard adjustment -0,78 ft)
Relative composite hull strength: 0,51