Refitted old sloop

[Korpen]

Well the combat value of the old Provence-class war sloops (light cruisers) are somewhat debated, as with a speed of less then 20kts, and only four guns they stand little chance in a fight against more modern ships.

But rather then scrapping them, it has been suggested they should undergo the following refit.
-all 15cm guns and ammo removed
-all but two 8,8cm guns removed
-Mine rails bolted on to the deck, enogh to carry about 200 mines
-a 10ton radio set added

The ships would then fullfill the role of fast minelayer for the next decade.

Provence Class, Netherlands minelayer laid down 1889

Displacement:
   3 652 t light; 3 742 t standard; 4 359 t normal; 4 853 t full load

Dimensions: Length overall / water x beam x draught
   328,08 ft / 328,08 ft x 49,21 ft x 19,03 ft (normal load)
   100,00 m / 100,00 m x 15,00 m  x 5,80 m

Armament:
      2 - 3,46" / 88,0 mm guns in single mounts, 19,84lbs / 9,00kg shells, 1900 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread
   Weight of broadside 40 lbs / 18 kg
   Shells per gun, main battery: 100

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   1,97" / 50 mm   328,08 ft / 100,00 m   9,84 ft / 3,00 m
   Ends:   Unarmoured
     Main Belt covers 154 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,39" / 10 mm         -               -

   - Armour deck: 1,97" / 50 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 9 000 ihp / 6 714 Kw = 19,33 kts
   Range 4 000nm at 12,00 kts
   Bunker at max displacement = 1 111 tons (100% coal)

Complement:
   267 - 348

Cost:
   £0,368 million / $1,470 million

Distribution of weights at normal displacement:
   Armament: 5 tons, 0,1 %
   Armour: 627 tons, 14,4 %
      - Belts: 235 tons, 5,4 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 1 tons, 0,0 %
      - Armour Deck: 391 tons, 9,0 %
      - Conning Tower: 0 tons, 0,0 %
   Machinery: 1 681 tons, 38,6 %
   Hull, fittings & equipment: 1 131 tons, 25,9 %
   Fuel, ammunition & stores: 707 tons, 16,2 %
   Miscellaneous weights: 208 tons, 4,8 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     2 709 lbs / 1 229 Kg = 132,3 x 3,5 " / 88 mm shells or 0,7 torpedoes
   Stability (Unstable if below 1.00): 1,56
   Metacentric height 3,7 ft / 1,1 m
   Roll period: 10,8 seconds
   Steadiness   - As gun platform (Average = 50 %): 72 %
         - Recoil effect (Restricted arc if above 1.00): 0,01
   Seaboat quality  (Average = 1.00): 1,45

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0,497
   Length to Beam Ratio: 6,67 : 1
   'Natural speed' for length: 18,11 kts
   Power going to wave formation at top speed: 50 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): -15,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      16,40 ft / 5,00 m
      - Forecastle (20 %):   13,12 ft / 4,00 m
      - Mid (35 %):      13,12 ft / 4,00 m (9,84 ft / 3,00 m aft of break)
      - Quarterdeck (15 %):   9,84 ft / 3,00 m
      - Stern:      9,84 ft / 3,00 m
      - Average freeboard:   11,25 ft / 3,43 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 131,2 %
      - Above water (accommodation/working, high = better): 81,1 %
   Waterplane Area: 10 724 Square feet or 996 Square metres
   Displacement factor (Displacement / loading): 103 %
   Structure weight / hull surface area: 69 lbs/sq ft or 337 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,94
      - Longitudinal: 1,67
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[maddox]

3,6 Ktons for transporting a few mines...

[Korpen]

3,6 Ktons for transporting a few mines...

I know it is overkill, but i can get them converted in less then two months.
Proper mine layers will be built as well :)

As i am surrounded everywhere by countries with much larger fleets (or simply much more concentrated) i feel the mine has to be a important weapon in the Dutch arsenal.
And they really have to be refitted if they are to continue in service, and i cannot afford to replace them all at once.

[maddox]

French shipyards would be glad to build minelayers for the Dutch neighbors.


Mineur, N/A Minelayer laid down 1906

Displacement:
   1.600 t light; 1.638 t standard; 1.724 t normal; 1.792 t full load

Dimensions: Length overall / water x beam x draught
   262,47 ft / 262,47 ft x 44,29 ft x 10,04 ft (normal load)
   80,00 m / 80,00 m x 13,50 m  x 3,06 m

Armament:
      2 - 3,94" / 100 mm guns in single mounts, 30,51lbs / 13,84kg shells, 1906 Model
     Breech loading guns in deck mounts
     on centreline, all forward, 1 raised mount
      2 - 0,31" / 8,0 mm guns in single mounts, 0,02lbs / 0,01kg shells, 1906 Model
     Breech loading guns in deck mounts
     on centreline, all aft, all raised mounts - superfiring
   Weight of broadside 61 lbs / 28 kg
   Shells per gun, main battery: 120
   2 - 17,7" / 450 mm above water torpedoes

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   No drive to shaft, 2 shafts, 6.550 ihp / 4.886 Kw = 20,00 kts
   Range 3.000nm at 8,00 kts
   Bunker at max displacement = 154 tons (100% coal)

Complement:
   133 - 173

Cost:
   £0,176 million / $0,703 million

Distribution of weights at normal displacement:
   Armament: 8 tons, 0,4%
   Machinery: 809 tons, 46,9%
   Hull, fittings & equipment: 563 tons, 32,7%
   Fuel, ammunition & stores: 124 tons, 7,2%
   Miscellaneous weights: 220 tons, 12,8%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     935 lbs / 424 Kg = 30,6 x 3,9 " / 100 mm shells or 0,4 torpedoes
   Stability (Unstable if below 1.00): 1,49
   Metacentric height 2,9 ft / 0,9 m
   Roll period: 10,9 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0,02
   Seaboat quality  (Average = 1.00): 1,21

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,517
   Length to Beam Ratio: 5,93 : 1
   'Natural speed' for length: 16,20 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   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:      19,69 ft / 6,00 m
      - Forecastle (20%):   13,12 ft / 4,00 m
      - Mid (50%):      11,35 ft / 3,46 m
      - Quarterdeck (15%):   11,35 ft / 3,46 m
      - Stern:      11,35 ft / 3,46 m
      - Average freeboard:   12,50 ft / 3,81 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 168,7%
      - Above water (accommodation/working, high = better): 121,3%
   Waterplane Area: 7.867 Square feet or 731 Square metres
   Displacement factor (Displacement / loading): 80%
   Structure weight / hull surface area: 51 lbs/sq ft or 247 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,92
      - Longitudinal: 2,03
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is excellent
   Good seaboat, rides out heavy weather easily

[Borys]

I would put 4 inch guns on her, as to keep enemy torpedoboats away.

Borys

[Korpen]

A modern purpose-built minelayer would look something like this.
Space for 300 mines, most under the deck as well as a 10t radio set.
A singel gun, it is expected that the ship will be escorted on offensive missions.
Enough speed and range to be able to operate with the fleet units.

Grävlingen, Netherlands Minelayer laid down 1906 (Engine 1905)

Displacement:
   1 800 t light; 1 846 t standard; 2 229 t normal; 2 535 t full load

Dimensions: Length overall / water x beam x draught
   335,73 ft / 328,08 ft x 42,65 ft x 9,84 ft (normal load)
   102,33 m / 100,00 m x 13,00 m  x 3,00 m

Armament:
      1 - 3,94" / 100 mm guns in single mounts, 37,48lbs / 17,00kg shells, 1906 Model
     Breech loading gun in deck mount
     on centreline forward
   Weight of broadside 37 lbs / 17 kg
   Shells per gun, main battery: 100

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,39" / 10 mm         -               -

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 8 800 shp / 6 564 Kw = 21,21 kts
   Range 4 000nm at 12,00 kts
   Bunker at max displacement = 689 tons (90% coal)

Complement:
   161 - 210

Cost:
   £0,168 million / $0,671 million

Distribution of weights at normal displacement:
   Armament: 4 tons, 0,2 %
   Armour: 1 tons, 0,0 %
      - Belts: 0 tons, 0,0 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 1 tons, 0,0 %
      - Armour Deck: 0 tons, 0,0 %
      - Conning Tower: 0 tons, 0,0 %
   Machinery: 726 tons, 32,6 %
   Hull, fittings & equipment: 759 tons, 34,1 %
   Fuel, ammunition & stores: 429 tons, 19,3 %
   Miscellaneous weights: 310 tons, 13,9 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     2 363 lbs / 1 072 Kg = 77,4 x 3,9 " / 100 mm shells or 0,7 torpedoes
   Stability (Unstable if below 1.00): 1,38
   Metacentric height 2,4 ft / 0,7 m
   Roll period: 11,5 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0,01
   Seaboat quality  (Average = 1.00): 1,40

Hull form characteristics:
   Hull has rise aft of midbreak
   Block coefficient: 0,566
   Length to Beam Ratio: 7,69 : 1
   'Natural speed' for length: 18,11 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 25,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      16,40 ft / 5,00 m
      - Forecastle (20 %):   12,47 ft / 3,80 m
      - Mid (70 %):      12,47 ft / 3,80 m (16,40 ft / 5,00 m aft of break)
      - Quarterdeck (15 %):   16,40 ft / 5,00 m
      - Stern:      16,40 ft / 5,00 m
      - Average freeboard:   13,96 ft / 4,26 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 122,1 %
      - Above water (accommodation/working, high = better): 156,9 %
   Waterplane Area: 9 917 Square feet or 921 Square metres
   Displacement factor (Displacement / loading): 124 %
   Structure weight / hull surface area: 52 lbs/sq ft or 255 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,95
      - Longitudinal: 1,52
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[Borys]

Pretty.

[Korpen]

Space for more then 200 mines and a small radio set.

Prikkeldraad, The Netherlands Minelayer laid down 1906 (Engine 1905)

Displacement:
   1 250 t light; 1 283 t standard; 1 588 t normal; 1 832 t full load

Dimensions: Length overall / water x beam x draught
   295,28 ft / 295,28 ft x 39,37 ft x 9,84 ft (normal load)
   90,00 m / 90,00 m x 12,00 m  x 3,00 m

Armament:
      1 - 3,94" / 100 mm guns in single mounts, 37,48lbs / 17,00kg shells, 1906 Model
     Breech loading gun in deck mount
     on centreline forward
   Weight of broadside 37 lbs / 17 kg
   Shells per gun, main battery: 80

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 6 000 shp / 4 476 Kw = 20,32 kts
   Range 4 000nm at 12,00 kts
   Bunker at max displacement = 548 tons (90% coal)

Complement:
   125 - 163

Cost:
   £0,116 million / $0,465 million

Distribution of weights at normal displacement:
   Armament: 4 tons, 0,2 %
   Machinery: 495 tons, 31,2 %
   Hull, fittings & equipment: 531 tons, 33,4 %
   Fuel, ammunition & stores: 338 tons, 21,3 %
   Miscellaneous weights: 220 tons, 13,9 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1 663 lbs / 754 Kg = 54,5 x 3,9 " / 100 mm shells or 0,6 torpedoes
   Stability (Unstable if below 1.00): 1,41
   Metacentric height 2,3 ft / 0,7 m
   Roll period: 11,0 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0,01
   Seaboat quality  (Average = 1.00): 1,39

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,486
   Length to Beam Ratio: 7,50 : 1
   'Natural speed' for length: 17,18 kts
   Power going to wave formation at top speed: 52 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   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:      19,69 ft / 6,00 m
      - Forecastle (20 %):   13,12 ft / 4,00 m
      - Mid (50 %):      9,84 ft / 3,00 m
      - Quarterdeck (15 %):   9,84 ft / 3,00 m
      - Stern:      9,84 ft / 3,00 m
      - Average freeboard:   11,52 ft / 3,51 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 118,1 %
      - Above water (accommodation/working, high = better): 123,5 %
   Waterplane Area: 7 647 Square feet or 710 Square metres
   Displacement factor (Displacement / loading): 128 %
   Structure weight / hull surface area: 48 lbs/sq ft or 232 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,96
      - Longitudinal: 1,48
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[Borys]

Nice.

[Korpen]

Nice.

And cheap :)

[Korpen]

Original ship: http://www.navalism.org/index.php?topic=679.msg4309#msg4309

The suggested modifications consist of replacing the engines with modern turbines and boilers

The suggested modifications consist of replacing the engines with modern turbines and boilers, mounting one more gun on the forecastle, this time in a raised position, fitting hoists to the guns and removing all the guns mounted behind the midbreak. Most of the space behind the midbreak will be taken up by a new mine hangar, allowing the ship to increase its carry capacity of mines to about 500. By sheltering the mines from the weather it is also possible for other high density cargo to be carried, such as ammunition, or for carrying troops short distances (sleeping in hammocks).
Oh, and all but the two forward torpedo tubes is removed.
The cost of the mod is estimated to be 1,7BP and €4,42.

While the hull shape does not really allow for the use of full speed in any but the calmest conditions (sea keeping is 1,0 at 24,85 kts), the speed should allow her to operate together with the fast elements of the fleet now under construction, giving rapid mine laying capacity to every part of the navy.



Simbawa, Netherlands Mine Sloop  laid down 1900 (Engine 1909)

Displacement:
   5 249 t light; 5 405 t standard; 6 358 t normal; 7 121 t full load

Dimensions: Length overall / water x beam x draught
   360,89 ft / 360,89 ft x 54,79 ft x 21,00 ft (normal load)
   110,00 m / 110,00 m x 16,70 m  x 6,40 m

Armament:
      2 - 5,91" / 150 mm guns in single mounts, 99,21lbs / 45,00kg shells, 1900 Model
     Breech loading guns in deck mounts with hoists
     on centreline, all forward, 1 raised mount
      2 - 5,91" / 150 mm guns in single mounts, 99,21lbs / 45,00kg shells, 1900 Model
     Breech loading guns in deck mounts with hoists
     on side, all forward
      4 - 3,46" / 88,0 mm guns in single mounts, 19,84lbs / 9,00kg shells, 1900 Model
     Quick firing guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 476 lbs / 216 kg
   Shells per gun, main battery: 100
   2 - 17,7" / 450 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   4,13" / 105 mm   328,08 ft / 100,00 m   9,84 ft / 3,00 m
   Ends:   1,97" / 50 mm     32,81 ft / 10,00 m   6,56 ft / 2,00 m
   Upper:   1,97" / 50 mm   328,08 ft / 100,00 m   8,20 ft / 2,50 m
     Main Belt covers 140 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,98" / 25 mm         -         1,97" / 50 mm
   2nd:   0,98" / 25 mm         -         1,97" / 50 mm
   3rd:   0,98" / 25 mm         -               -

   - Armour deck: 1,97" / 50 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 4 shafts, 36 682 shp / 27 365 Kw = 25,94 kts
   Range 9 500nm at 12,00 kts
   Bunker at max displacement = 1 715 tons

Complement:
   355 - 462

Cost:
   £0,469 million / $1,876 million

Distribution of weights at normal displacement:
   Armament: 62 tons, 1,0 %
   Armour: 1 283 tons, 20,2 %
      - Belts: 764 tons, 12,0 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 23 tons, 0,4 %
      - Armour Deck: 496 tons, 7,8 %
      - Conning Tower: 0 tons, 0,0 %
   Machinery: 1 667 tons, 26,2 %
   Hull, fittings & equipment: 1 706 tons, 26,8 %
   Fuel, ammunition & stores: 1 110 tons, 17,5 %
   Miscellaneous weights: 530 tons, 8,3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     6 659 lbs / 3 020 Kg = 64,7 x 5,9 " / 150 mm shells or 1,2 torpedoes
   Stability (Unstable if below 1.00): 1,24
   Metacentric height 3,0 ft / 0,9 m
   Roll period: 13,3 seconds
   Steadiness   - As gun platform (Average = 50 %): 45 %
         - Recoil effect (Restricted arc if above 1.00): 0,12
   Seaboat quality  (Average = 1.00): 0,81

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0,536
   Length to Beam Ratio: 6,59 : 1
   'Natural speed' for length: 19,00 kts
   Power going to wave formation at top speed: 65 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): -15,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      21,33 ft / 6,50 m
      - Forecastle (20 %):   21,33 ft / 6,50 m
      - Mid (40 %):      21,33 ft / 6,50 m (13,12 ft / 4,00 m aft of break)
      - Quarterdeck (15 %):   13,12 ft / 4,00 m
      - Stern:      13,12 ft / 4,00 m
      - Average freeboard:   16,40 ft / 5,00 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 101,8 %
      - Above water (accommodation/working, high = better): 108,7 %
   Waterplane Area: 13 620 Square feet or 1 265 Square metres
   Displacement factor (Displacement / loading): 113 %
   Structure weight / hull surface area: 78 lbs/sq ft or 381 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,90
      - Longitudinal: 2,38
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is adequate
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather



Any thoughts?

[The Rock Doctor]

For the cost of the refit, and the ship's scrap value, can you do better?

[Korpen]

For the cost of the refit, and the ship's scrap value, can you do better?

Not really I am afraid, as such a ship would only weight in at 2500 ton.
While I normally prefer mine warfare vessels to be smaller (as it is a high-risk job) then this one, in this case it does offer a ships that is quite usefull for autonomous operations.
The 2,5k ton ships I have been looking at can maybe take the same mine load, but are then pretty much unarmed and unarmoured, they are relatively better seaboats however, but I suspect the size difference closes the gap there. I imagine that simbawa would make a nice companion for the frigates now under construction, laying mines in your wake is a nice way to discourage pursuit.

But if anyone feels they got a design of a 2,5ton mine cruiser (25kts max speed, 9000nm@12kts, 500 mines/cargo, effective self defence armament, armour a plus) that would be an improvement over the refit; I would very much like to see it! :)

[The Rock Doctor]

Not quite, but I reckon it's not a bad design for a new-build with 1912 engines:


Enter ship name, Enter country Enter ship type laid down 1910 (Engine 1912)

Displacement:
   2,552 t light; 2,645 t standard; 3,177 t normal; 3,602 t full load

Dimensions: Length overall / water x beam x draught
   397.63 ft / 393.70 ft x 36.09 ft x 17.39 ft (normal load)
   121.20 m / 120.00 m x 11.00 m  x 5.30 m

Armament:
      4 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1910 Model
     Breech loading guns in deck mounts with hoists
     on centreline ends, evenly spread, 2 raised mounts - superfiring
      2 - 3.46" / 88.0 mm guns in single mounts, 20.79lbs / 9.43kg shells, 1910 Model
     Breech loading guns in deck mounts
     on side, all amidships
   Weight of broadside 252 lbs / 115 kg
   Shells per gun, main battery: 200

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.95" / 75 mm   255.91 ft / 78.00 m   7.51 ft / 2.29 m
   Ends:   0.98" / 25 mm   137.76 ft / 41.99 m   7.51 ft / 2.29 m
   Upper:   0.98" / 25 mm   255.91 ft / 78.00 m   8.01 ft / 2.44 m
     Main Belt covers 100 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.98" / 25 mm         -         0.98" / 25 mm
   2nd:   0.98" / 25 mm         -               -

   - Armour deck: 0.98" / 25 mm, Conning tower: 2.95" / 75 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 18,000 shp / 13,428 Kw = 25.10 kts
   Range 9,000nm at 12.00 kts (Bunkerage = 957 tons)

Complement:
   211 - 275

Cost:
   £0.216 million / $0.865 million

Distribution of weights at normal displacement:
   Armament: 32 tons, 1.0 %
   Armour: 549 tons, 17.3 %
      - Belts: 355 tons, 11.2 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 15 tons, 0.5 %
      - Armour Deck: 165 tons, 5.2 %
      - Conning Tower: 14 tons, 0.4 %
   Machinery: 718 tons, 22.6 %
   Hull, fittings & equipment: 974 tons, 30.7 %
   Fuel, ammunition & stores: 625 tons, 19.7 %
   Miscellaneous weights: 280 tons, 8.8 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,458 lbs / 1,569 Kg = 65.6 x 4.7 " / 120 mm shells or 0.9 torpedoes
   Stability (Unstable if below 1.00): 1.11
   Metacentric height 1.3 ft / 0.4 m
   Roll period: 13.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 58 %
         - Recoil effect (Restricted arc if above 1.00): 0.25
   Seaboat quality  (Average = 1.00): 1.19

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.450
   Length to Beam Ratio: 10.91 : 1
   'Natural speed' for length: 19.84 kts
   Power going to wave formation at top speed: 50 %
   Trim (Max stability = 0, Max steadiness = 100): 49
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      22.31 ft / 6.80 m
      - Forecastle (20 %):   16.40 ft / 5.00 m
      - Mid (40 %):      16.40 ft / 5.00 m (8.53 ft / 2.60 m aft of break)
      - Quarterdeck (15 %):   8.53 ft / 2.60 m
      - Stern:      8.53 ft / 2.60 m
      - Average freeboard:   12.15 ft / 3.70 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 91.4 %
      - Above water (accommodation/working, high = better): 89.6 %
   Waterplane Area: 9,063 Square feet or 842 Square metres
   Displacement factor (Displacement / loading): 126 %
   Structure weight / hull surface area: 59 lbs/sq ft or 290 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.39
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is cramped

[Korpen]

Orginal ship: http://www.navalism.org/index.php?topic=691.0
Fairly simple modification, the eight torpedo tubes are landed, and instead she is fitted with a mine hangar and mine rails with a capacity for 120 mines (or other cargo), new engines and boilers raise her speed with 2,5 kts and range by 3000nm.  One more gun is added forward is a raised position, and she will get a better looking superstructure.
The total cost of the modifications would be 1,3 BP, and about 3€.
The mod would allow the ship to fulfil the role of minelayer-leader of TB squadrons, or as autonomous minelayers, possibly in support of frigates.
So is it worth it?

Jäger-class, Netherlands Corvette laid down 1901 (Engine 1909)

Displacement:
   2 536 t light; 2 620 t standard; 3 080 t normal; 3 447 t full load

Dimensions: Length overall / water x beam x draught
   354,43 ft / 344,49 ft x 42,65 ft x 17,06 ft (normal load)
   108,03 m / 105,00 m x 13,00 m  x 5,20 m

Armament:
      4 - 4,72" / 120 mm guns in single mounts, 52,91lbs / 24,00kg shells, 1901 Model
     Quick firing guns in deck mounts with hoists
     on centreline ends, evenly spread, 2 raised mounts - superfiring
      2 - 3,46" / 88,0 mm guns in single mounts, 19,84lbs / 9,00kg shells, 1901 Model
     Quick firing guns in deck mounts
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 251 lbs / 114 kg
   Shells per gun, main battery: 150

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,98" / 25 mm         -               -
   2nd:   0,98" / 25 mm         -               -

   - Conning tower: 0,98" / 25 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 4 shafts, 28 000 shp / 20 888 Kw = 27,55 kts
   Range 7 000nm at 12,00 kts
   Bunker at max displacement = 828 tons

Complement:
   206 - 268

Cost:
   £0,293 million / $1,174 million

Distribution of weights at normal displacement:
   Armament: 32 tons, 1,0 %
   Armour: 18 tons, 0,6 %
      - Belts: 0 tons, 0,0 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 14 tons, 0,5 %
      - Armour Deck: 0 tons, 0,0 %
      - Conning Tower: 4 tons, 0,1 %
   Machinery: 1 273 tons, 41,3 %
   Hull, fittings & equipment: 1 034 tons, 33,6 %
   Fuel, ammunition & stores: 543 tons, 17,6 %
   Miscellaneous weights: 180 tons, 5,8 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1 745 lbs / 791 Kg = 33,1 x 4,7 " / 120 mm shells or 0,5 torpedoes
   Stability (Unstable if below 1.00): 1,35
   Metacentric height 2,4 ft / 0,7 m
   Roll period: 11,6 seconds
   Steadiness   - As gun platform (Average = 50 %): 51 %
         - Recoil effect (Restricted arc if above 1.00): 0,15
   Seaboat quality  (Average = 1.00): 0,99

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0,430
   Length to Beam Ratio: 8,08 : 1
   'Natural speed' for length: 18,56 kts
   Power going to wave formation at top speed: 62 %
   Trim (Max stability = 0, Max steadiness = 100): 51
   Bow angle (Positive = bow angles forward): 25,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      21,33 ft / 6,50 m
      - Forecastle (20 %):   19,69 ft / 6,00 m
      - Mid (35 %):      19,69 ft / 6,00 m (11,48 ft / 3,50 m aft of break)
      - Quarterdeck (15 %):   11,48 ft / 3,50 m
      - Stern:      11,48 ft / 3,50 m
      - Average freeboard:   14,48 ft / 4,42 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 148,0 %
      - Above water (accommodation/working, high = better): 114,1 %
   Waterplane Area: 9 226 Square feet or 857 Square metres
   Displacement factor (Displacement / loading): 103 %
   Structure weight / hull surface area: 65 lbs/sq ft or 317 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,91
      - Longitudinal: 2,32
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is adequate
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather