Harbour defense vessels

[swamphen]

Concept Anton. 'Heavy' harbour defense gunboat. Intended to operate in concert with slighly smaller vessels mounting more, smaller guns. 1x170mm for punching big holes, torpedoes for finishing off vessels crippled by the lighter, non-torpedo-armed ships. Splinterproof decking. Minimal speed and bunkerage - it's not intended to operate very far, if any, outside the harbour perimeter.

PB09A, Brandenburgian Harbour Patrol Vessel laid down 1909

Displacement:
   446 t light; 470 t standard; 503 t normal; 529 t full load

Dimensions: Length overall / water x beam x draught
   205.05 ft / 205.05 ft x 32.81 ft x 4.76 ft (normal load)
   62.50 m / 62.50 m x 10.00 m  x 1.45 m

Armament:
      1 - 6.69" / 170 mm guns in single mounts, 149.91lbs / 68.00kg shells, 1909 Model
     Breech loading gun in a deck mount with hoist
     on centreline forward
      2 - 1.97" / 50.0 mm guns in single mounts, 3.86lbs / 1.75kg shells, 1903 Model
     Quick firing guns in deck mounts
     on side, all aft
      4 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.01kg shells, 1909 Model
     Machine guns in deck mounts
     on side ends, evenly spread

   Weight of broadside 158 lbs / 72 kg
   Shells per gun, main battery: 150

   2 - 17.7" / 450 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.98" / 25 mm   0.39" / 10 mm      0.79" / 20 mm

   - Armour deck: 0.39" / 10 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 250 ihp / 186 Kw = 9.83 kts
   Range 1,500nm at 9.83 kts (Bunkerage = 60 tons)

Complement:
   53 - 69

Cost:
   £0.035 million / $0.139 million

Distribution of weights at normal displacement:
   Armament: 20 tons, 3.9 %
   Armour: 38 tons, 7.5 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 3 tons, 0.7 %
      - Armour Deck: 34 tons, 6.8 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 19 tons, 3.8 %
   Hull, fittings & equipment: 320 tons, 63.6 %
   Fuel, ammunition & stores: 57 tons, 11.3 %
   Miscellaneous weights: 50 tons, 9.9 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,851 lbs / 840 Kg = 12.4 x 6.7 " / 170 mm shells or 1.2 torpedoes
   Stability (Unstable if below 1.00): 1.16
   Metacentric height 1.2 ft / 0.4 m
   Roll period: 12.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 72 %
         - Recoil effect (Restricted arc if above 1.00): 0.35
   Seaboat quality  (Average = 1.00): 1.70

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.550
   Length to Beam Ratio: 6.25 : 1
   'Natural speed' for length: 14.32 kts
   Power going to wave formation at top speed: 25 %
   Trim (Max stability = 0, Max steadiness = 100): 42
   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:      18.04 ft / 5.50 m
      - Forecastle (20 %):   17.22 ft / 5.25 m
      - Mid (35 %):      16.40 ft / 5.00 m (8.20 ft / 2.50 m aft of break)
      - Quarterdeck (15 %):   8.20 ft / 2.50 m
      - Stern:      8.20 ft / 2.50 m
      - Average freeboard:   11.36 ft / 3.46 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 54.4 %
      - Above water (accommodation/working, high = better): 146.9 %
   Waterplane Area: 4,695 Square feet or 436 Square metres
   Displacement factor (Displacement / loading): 177 %
   Structure weight / hull surface area: 48 lbs/sq ft or 235 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.87
      - Longitudinal: 3.39
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[The Rock Doctor]

To my own thinking, the harbour defence vessel is primarily a police craft - something big enough to fire a warning shot, a few machine guns to cover boarders, and enough speed to catch most merchants.  It shouldn't be their job to repel attacks - only to warn of them so that the larger ships in harbour, or the shore batteries, can deal with them.

Might make a useful fire-support vessel along coasts or up rivers, though...

[Korpen]

Concept Anton. 'Heavy' harbour defense gunboat. Intended to operate in concert with slighly smaller vessels mounting more, smaller guns. 1x170mm for punching big holes, torpedoes for finishing off vessels crippled by the lighter, non-torpedo-armed ships. Splinterproof decking. Minimal speed and bunkerage - it's not intended to operate very far, if any, outside the harbour perimeter.

PB09A, Brandenburgian Harbour Patrol Vessel laid down 1909

I think it is pointless.
For the same cost as one of these ships you could emplace 2-3 17cm guns instead, something that is MUCH more survivable if attacked. These ships are a 60m long, vulnerable target, a well-emplaced 17cm gun is a 2m2  large target that needs a direct hit to destroy.
The same goes for costal torpedo batteries, they are minimal targets, and very hard to hit at any distance.

[Carthaginian]

This is what my Santa Bouge class was conceived for. Something small, armored against light surface combatant gunfire, and capable of delivering a frightening punch. Granted, she's a lot more expensive, but she's also able to make a cruiser thing twice about coming too close ashore.

[Korpen]

While I do not believe in the concept, it does offer some outlandish designs. :)
So here is a design for a dedicated harbour defence ship.
She is armoured against cruiser fire, and the weather deck is also the armoured deck, so all parts of the ship above water is armoured, the main bale going from stern to stem. The single torpedo tube is places below water in the stern, and have three torpedoes.
A full turret was selected as under the circumstances a barbarette would not fit, and deck mounts are too vulnerable.

I would name her "Monitor" ;)

Monitor, DKB Monitor laid down 1909

Displacement:
   400 t light; 416 t standard; 419 t normal; 421 t full load

Dimensions: Length overall / water x beam x draught
   114,92 ft / 114,83 ft x 26,25 ft x 5,91 ft (normal load)
   35,03 m / 35,00 m x 8,00 m  x 1,80 m

Armament:
      1 - 6,69" / 170 mm guns in single mounts, 149,90lbs / 68,00kg shells, 1909 Model
     Breech loading gun in Coles/Ericsson turret
     on centreline amidships
      4 - 0,30" / 7,7 mm guns in single mounts, 0,01lbs / 0,01kg shells, 1909 Model
     Machine guns in casemate mounts
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 150 lbs / 68 kg
   Shells per gun, main battery: 100
   1 - 17,7" / 450 mm submerged torpedo tubes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   4,13" / 105 mm   114,83 ft / 35,00 m   5,91 ft / 1,80 m
   Ends:   Unarmoured
     Main Belt covers 154 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   4,13" / 105 mm   4,13" / 105 mm            -

   - Armour deck: 2,17" / 55 mm

Machinery:
   Diesel Internal combustion motors,
   Direct drive, 2 shafts, 187 shp / 139 Kw = 9,00 kts
   Range 200nm at 5,00 kts
   Bunker at max displacement = 5 tons

Complement:
   46 - 60

Cost:
   £0,031 million / $0,124 million

Distribution of weights at normal displacement:
   Armament: 19 tons, 4,5 %
   Armour: 236 tons, 56,2 %
      - Belts: 104 tons, 24,8 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 24 tons, 5,8 %
      - Armour Deck: 108 tons, 25,7 %
      - Conning Tower: 0 tons, 0,0 %
   Machinery: 8 tons, 2,0 %
   Hull, fittings & equipment: 134 tons, 31,9 %
   Fuel, ammunition & stores: 19 tons, 4,6 %
   Miscellaneous weights: 3 tons, 0,7 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     873 lbs / 396 Kg = 5,8 x 6,7 " / 170 mm shells or 1,0 torpedoes
   Stability (Unstable if below 1.00): 1,32
   Metacentric height 1,1 ft / 0,3 m
   Roll period: 10,5 seconds
   Steadiness   - As gun platform (Average = 50 %): 55 %
         - Recoil effect (Restricted arc if above 1.00): 0,21
   Seaboat quality  (Average = 1.00): 1,10

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,824
   Length to Beam Ratio: 4,38 : 1
   'Natural speed' for length: 10,72 kts
   Power going to wave formation at top speed: 47 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 1,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      4,92 ft / 1,50 m
      - Forecastle (20 %):   3,94 ft / 1,20 m
      - Mid (50 %):      3,94 ft / 1,20 m
      - Quarterdeck (15 %):   3,94 ft / 1,20 m
      - Stern:      3,94 ft / 1,20 m
      - Average freeboard:   4,02 ft / 1,22 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 47,5 %
      - Above water (accommodation/working, high = better): 43,8 %
   Waterplane Area: 2 687 Square feet or 250 Square metres
   Displacement factor (Displacement / loading): 103 %
   Structure weight / hull surface area: 41 lbs/sq ft or 202 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,93
      - Longitudinal: 1,88
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is extremely poor

[maddox]

Something the MK was cooking up, before Phoenix started using SS herself. These  tough guys are bigger than the DKB proposals, but still good value for money.

Renzi class, Middle Kingdom river monitor laid down 1908

Displacement:
   1.000 t light; 1.051 t standard; 1.114 t normal; 1.164 t full load

Dimensions: Length overall / water x beam x draught
   204,97 ft / 196,85 ft x 37,73 ft x 7,22 ft (normal load)
   62,48 m / 60,00 m x 11,50 m  x 2,20 m

Armament:
      2 - 5,51" / 140 mm guns (1x2 guns), 83,72lbs / 37,98kg shells, 1908 Model
     Breech loading guns in a turret (on a barbette)
     on centreline amidships
      6 - 2,95" / 75,0 mm guns in single mounts, 12,87lbs / 5,84kg shells, 1908 Model
     Quick firing guns in deck mounts
     on side ends, evenly spread
      10 - 0,98" / 25,0 mm guns in single mounts, 0,48lbs / 0,22kg shells, 1908 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 249 lbs / 113 kg
   Shells per gun, main battery: 180
   2 - 20,0" / 508 mm submerged torpedo tubes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3,15" / 80 mm   196,85 ft / 60,00 m   6,56 ft / 2,00 m
   Ends:   Unarmoured
   Upper:   3,15" / 80 mm   131,23 ft / 40,00 m   6,56 ft / 2,00 m
     Main Belt covers 154% of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   3,15" / 80 mm   3,15" / 80 mm      3,15" / 80 mm
   2nd:   0,79" / 20 mm   0,39" / 10 mm            -

   - Armour deck: 1,97" / 50 mm

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 1 shaft, 612 shp / 457 Kw = 11,00 kts
   Range 1.500nm at 10,00 kts
   Bunker at max displacement = 113 tons (100% coal)

Complement:
   96 - 125

Cost:
   £0,066 million / $0,264 million

Distribution of weights at normal displacement:
   Armament: 31 tons, 2,8%
   Armour: 536 tons, 48,2%
      - Belts: 272 tons, 24,5%
      - Torpedo bulkhead: 0 tons, 0,0%
      - Armament: 43 tons, 3,8%
      - Armour Deck: 221 tons, 19,9%
      - Conning Tower: 0 tons, 0,0%
   Machinery: 34 tons, 3,1%
   Hull, fittings & equipment: 377 tons, 33,8%
   Fuel, ammunition & stores: 113 tons, 10,2%
   Miscellaneous weights: 22 tons, 2,0%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3.558 lbs / 1.614 Kg = 42,5 x 5,5 " / 140 mm shells or 2,0 torpedoes
   Stability (Unstable if below 1.00): 1,38
   Metacentric height 2,0 ft / 0,6 m
   Roll period: 11,1 seconds
   Steadiness   - As gun platform (Average = 50 %): 72 %
         - Recoil effect (Restricted arc if above 1.00): 0,16
   Seaboat quality  (Average = 1.00): 1,45

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0,727
   Length to Beam Ratio: 5,22 : 1
   'Natural speed' for length: 14,03 kts
   Power going to wave formation at top speed: 39 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10,00 degrees
   Stern overhang: 6,56 ft / 2,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      8,86 ft / 2,70 m
      - Forecastle (20%):   8,86 ft / 2,70 m (7,55 ft / 2,30 m aft of break)
      - Mid (50%):      7,55 ft / 2,30 m
      - Quarterdeck (15%):   7,55 ft / 2,30 m
      - Stern:      8,20 ft / 2,50 m
      - Average freeboard:   7,86 ft / 2,40 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 40,0%
      - Above water (accommodation/working, high = better): 91,0%
   Waterplane Area: 6.079 Square feet or 565 Square metres
   Displacement factor (Displacement / loading): 127%
   Structure weight / hull surface area: 50 lbs/sq ft or 243 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,95
      - Longitudinal: 1,63
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

Harbor and coastal defence ship.

30 tons misc.
4 reloads for each of the 2 broadside tubes

10 tons for a short ranged maroni.