WesWorld

Playing with SS for the first time in a while.

KMS Tärnö, Other Minewarfare laid down 1945

Displacement:
326 t light; 335 t standard; 424 t normal; 495 t full load

Dimensions: Length overall / water x beam x draught
137,80 ft / 137,80 ft x 22,97 ft x 8,53 ft (normal load)
42,00 m / 42,00 m x 7,00 m x 2,60 m

Armament:
4 - 1,57" / 40,0 mm guns (2x2 guns), 1,95lbs / 0,89kg shells, 1945 Model
Automatic rapid fire guns in turrets (on barbettes)
on centreline ends, evenly spread
4 - 0,52" / 13,2 mm guns (2x2 guns), 0,07lbs / 0,03kg shells, 1945 Model
Machine guns in deck mounts
on side, all amidships
Weight of broadside 8 lbs / 4 kg
Shells per gun, main battery: 150

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1,57" / 40 mm 0,79" / 20 mm 0,79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 3 905 shp / 2 913 Kw = 20,00 kts
Range 1 500nm at 20,00 kts
Bunker at max displacement = 160 tons

Complement:
46 - 60

Cost:
£0,181 million / $0,725 million

Distribution of weights at normal displacement:
Armament: 1 tons, 0,3 %
Armour: 6 tons, 1,4 %
- Belts: 0 tons, 0,0 %
- Torpedo bulkhead: 0 tons, 0,0 %
- Armament: 6 tons, 1,4 %
- Armour Deck: 0 tons, 0,0 %
- Conning Tower: 0 tons, 0,0 %
Machinery: 99 tons, 23,2 %
Hull, fittings & equipment: 171 tons, 40,2 %
Fuel, ammunition & stores: 98 tons, 23,1 %
Miscellaneous weights: 50 tons, 11,8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
702 lbs / 318 Kg = 359,4 x 1,6 " / 40 mm shells or 0,5 torpedoes
Stability (Unstable if below 1.00): 1,04
Metacentric height 0,6 ft / 0,2 m
Roll period: 12,5 seconds
Steadiness - As gun platform (Average = 50 %): 56 %
- Recoil effect (Restricted arc if above 1.00): 0,07
Seaboat quality (Average = 1.00): 1,27

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,550
Length to Beam Ratio: 6,00 : 1
'Natural speed' for length: 11,74 kts
Power going to wave formation at top speed: 75 %
Trim (Max stability = 0, Max steadiness = 100): 44
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: 13,12 ft / 4,00 m
- Forecastle (20 %): 13,12 ft / 4,00 m
- Mid (50 %): 13,12 ft / 4,00 m
- Quarterdeck (15 %): 13,12 ft / 4,00 m
- Stern: 13,12 ft / 4,00 m
- Average freeboard: 13,12 ft / 4,00 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 91,0 %
- Above water (accommodation/working, high = better): 120,0 %
Waterplane Area: 2 209 Square feet or 205 Square metres
Displacement factor (Displacement / loading): 162 %
Structure weight / hull surface area: 31 lbs/sq ft or 154 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,75
- Longitudinal: 16,84
- Overall: 1,02
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Good seaboat, rides out heavy weather easily

I'd say "Turret and Barbette" is overkill for a 40mm, even if it is a "Automatic Rapid Fire".

Cruise speed is too high, minesweeping is done at slow speed, and that's it's main job. I'd set cruising speed to 10-12kts (which is actually probably still faster than you'll be going while sweeping).

Armor on the 40mm is A) overkill and B) pointless. If something is shooting at this ship the 40mm won't matter cuz it will be on the bottom anyway. If you want weather shielding for the mount 5mm is plenty and anything over 10mm is too much.

How are you breaking down the 50t misc weight?

Good point about the armor, I havent broken down the misc weight but its for minesweeping and laying equipment as well as mines

KMS Tärnö, Other Minewarfare laid down 1945

Displacement:
326 t light; 335 t standard; 424 t normal; 495 t full load

Dimensions: Length overall / water x beam x draught
137,80 ft / 137,80 ft x 22,97 ft x 8,53 ft (normal load)
42,00 m / 42,00 m x 7,00 m x 2,60 m

Armament:
4 - 1,57" / 40,0 mm guns (2x2 guns), 1,95lbs / 0,88kg shells, 1945 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread
4 - 0,52" / 13,2 mm guns (2x2 guns), 0,07lbs / 0,03kg shells, 1945 Model
Machine guns in deck mounts
on side, all amidships
Weight of broadside 8 lbs / 4 kg
Shells per gun, main battery: 150

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

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 3 905 shp / 2 913 Kw = 20,00 kts
Range 1 500nm at 20,00 kts
Bunker at max displacement = 160 tons

Complement:
46 - 60

Cost:
£0,181 million / $0,725 million

Distribution of weights at normal displacement:
Armament: 1 tons, 0,3 %
Armour: 1 tons, 0,3 %
- Belts: 0 tons, 0,0 %
- Torpedo bulkhead: 0 tons, 0,0 %
- Armament: 1 tons, 0,3 %
- Armour Deck: 0 tons, 0,0 %
- Conning Tower: 0 tons, 0,0 %
Machinery: 99 tons, 23,2 %
Hull, fittings & equipment: 175 tons, 41,3 %
Fuel, ammunition & stores: 98 tons, 23,1 %
Miscellaneous weights: 50 tons, 11,8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
704 lbs / 319 Kg = 360,5 x 1,6 " / 40 mm shells or 0,5 torpedoes
Stability (Unstable if below 1.00): 1,05
Metacentric height 0,6 ft / 0,2 m
Roll period: 12,4 seconds
Steadiness - As gun platform (Average = 50 %): 56 %
- Recoil effect (Restricted arc if above 1.00): 0,07
Seaboat quality (Average = 1.00): 1,28

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,550
Length to Beam Ratio: 6,00 : 1
'Natural speed' for length: 11,74 kts
Power going to wave formation at top speed: 75 %
Trim (Max stability = 0, Max steadiness = 100): 44
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: 13,12 ft / 4,00 m
- Forecastle (20 %): 13,12 ft / 4,00 m
- Mid (50 %): 13,12 ft / 4,00 m
- Quarterdeck (15 %): 13,12 ft / 4,00 m
- Stern: 13,12 ft / 4,00 m
- Average freeboard: 13,12 ft / 4,00 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 91,0 %
- Above water (accommodation/working, high = better): 120,0 %
Waterplane Area: 2 209 Square feet or 205 Square metres
Displacement factor (Displacement / loading): 164 %
Structure weight / hull surface area: 32 lbs/sq ft or 158 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,77
- Longitudinal: 17,59
- Overall: 1,06
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Good seaboat, rides out heavy weather easily