WesWorld

Since my idea of a heavy destroyer was received as it was , I've decided to post some more 'sedate' designs here. These will be the patrol craft and smaller minelayers that I'm planning to add to my fleet over the next year or so. They are both going to be extremely small ships and pretty much in line with what one would expect from Siam... though the patrol ships will be a bit faster (24 knots) than people would expect in order to double as AA escorts for my Dhonburi class CDS.

So, here's the minelayer. She's very simple, perhaps a bit over-gunned for her size, but with aircraft becoming an increasing hazard, I'd prefer to over-gun than under-gun.

Quoted

ML-1, Siamese Minelayer laid down 1936

Displacement:
200 t light; 210 t standard; 245 t normal; 273 t full load

Dimensions: Length overall / water x beam x draught
164.04 ft / 164.04 ft x 20.51 ft x 4.92 ft (normal load)
50.00 m / 50.00 m x 6.25 m x 1.50 m

Armament:
2 - 3.00" / 76.2 mm guns (1x2 guns), 13.23lbs / 6.00kg shells, 1936 Model
Dual purpose guns in a deck mount with hoist
on centreline forward
6 - 0.79" / 20.0 mm guns (2x3 guns), 0.22lbs / 0.10kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
3 - 0.79" / 20.0 mm guns (1x3 guns), 0.22lbs / 0.10kg shells, 1936 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
Weight of broadside 28 lbs / 13 kg
Shells per gun, main battery: 300

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.79" / 20 mm 0.79" / 20 mm 0.79" / 20 mm
2nd: 0.79" / 20 mm - -
3rd: 0.79" / 20 mm - -

- Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 800 shp / 597 Kw = 15.43 kts
Range 2,000nm at 15.43 kts
Bunker at max displacement = 62 tons

Complement:
30 - 40

Cost:
£0.070 million / $0.279 million

Distribution of weights at normal displacement:
Armament: 4 tons, 1.5 %
Armour: 4 tons, 1.8 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 4 tons, 1.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 1 tons, 0.3 %
Machinery: 22 tons, 9.2 %
Hull, fittings & equipment: 116 tons, 47.3 %
Fuel, ammunition & stores: 45 tons, 18.2 %
Miscellaneous weights: 54 tons, 22.0 %
Storage for 72 mines (1500 lbs each)

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
603 lbs / 274 Kg = 44.7 x 3.0 " / 76 mm shells or 0.6 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 0.6 ft / 0.2 m
Roll period: 11.6 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.28
Seaboat quality (Average = 1.00): 1.87

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.518
Length to Beam Ratio: 8.00 : 1
'Natural speed' for length: 12.81 kts
Power going to wave formation at top speed: 51 %
Trim (Max stability = 0, Max steadiness = 100): 38
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: 14.76 ft / 4.50 m
- Forecastle (20 %): 9.02 ft / 2.75 m
- Mid (50 %): 8.20 ft / 2.50 m
- Quarterdeck (15 %): 7.38 ft / 2.25 m
- Stern: 6.56 ft / 2.00 m
- Average freeboard: 8.62 ft / 2.63 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 67.2 %
- Above water (accommodation/working, high = better): 118.2 %
Waterplane Area: 2,279 Square feet or 212 Square metres
Displacement factor (Displacement / loading): 185 %
Structure weight / hull surface area: 29 lbs/sq ft or 142 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.86
- Longitudinal: 3.62
- 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
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

And this is the patrol/escort ship. She's rather fast as far as WW sloops go (25 knots) to enable her to serve in formation with the Dhonburi. She's got a moderately heavy collection of 37mm and 20mm AA guns, and 2 twin 76mm DP mounts. She'll also mount ASDIC and depth charges in order to serve as an ASW screening vessel. Additionally, she'll also carry berthing for two squads of Marines (1 ton per man- a bunk, a locker and a couple of basic loads) to better help her conduct customs inspections during peacetime... and to give her the chance to capture the odd merchantman or disabled sub during wartime should the opportunity arise.

Quoted

Chiang Dao, Siamese Patrol Sloop laid down 1936

Displacement:
600 t light; 625 t standard; 674 t normal; 713 t full load

Dimensions: Length overall / water x beam x draught
236.23 ft / 229.66 ft x 26.25 ft x 9.84 ft (normal load)
72.00 m / 70.00 m x 8.00 m x 3.00 m

Armament:
4 - 3.00" / 76.2 mm guns (2x2 guns), 13.23lbs / 6.00kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1936 Model
Dual purpose guns in deck mounts
on side, all amidships, all raised mounts - superfiring
12 - 0.79" / 20.0 mm guns (4x3 guns), 0.22lbs / 0.10kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 62 lbs / 28 kg
Shells per gun, main battery: 300

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.98" / 25 mm 0.98" / 25 mm 0.98" / 25 mm
2nd: 0.98" / 25 mm - -
3rd: 0.98" / 25 mm - -

- Conning tower: 0.98" / 25 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 7,000 shp / 5,222 Kw = 24.95 kts
Range 3,000nm at 12.80 kts
Bunker at max displacement = 87 tons

Complement:
65 - 85

Cost:
£0.291 million / $1.163 million

Distribution of weights at normal displacement:
Armament: 8 tons, 1.2 %
Armour: 12 tons, 1.9 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 11 tons, 1.6 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.2 %
Machinery: 196 tons, 29.1 %
Hull, fittings & equipment: 336 tons, 49.8 %
Fuel, ammunition & stores: 74 tons, 10.9 %
Miscellaneous weights: 48 tons, 7.1 %
8 tons - ASDIC
20 tons - 40 depth charges
20 tons - Marine berthing (20 Marines)

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
845 lbs / 383 Kg = 62.6 x 3.0 " / 76 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.12
Metacentric height 0.8 ft / 0.3 m
Roll period: 12.1 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.25
Seaboat quality (Average = 1.00): 1.42

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.398
Length to Beam Ratio: 8.75 : 1
'Natural speed' for length: 17.74 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 20.00 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 %): 13.12 ft / 4.00 m
- Mid (50 %): 12.30 ft / 3.75 m
- Quarterdeck (10 %): 11.48 ft / 3.50 m
- Stern: 10.66 ft / 3.25 m
- Average freeboard: 12.70 ft / 3.87 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 112.5 %
- Above water (accommodation/working, high = better): 138.0 %
Waterplane Area: 3,845 Square feet or 357 Square metres
Displacement factor (Displacement / loading): 131 %
Structure weight / hull surface area: 41 lbs/sq ft or 198 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.82
- Longitudinal: 6.09
- 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

I note that Chiang Dao is trimmed down heavily. That means you likely have extra seakeeping. Now, light small craft can have less than 1.0 comp hull, so you can push the speed up if you want.

Don't know about ASDIC, seems a bunch of nations have it and many don't. No clue as to Siam/ Denmark. RAM indicated the Dutch didn't so until recently I've been installing hydrophones until Phillips Electronics came through for me...

Quoted

Originally posted by Kaiser Kirk
I note that Chiang Dao is trimmed down heavily. That means you likely have extra seakeeping. Now, light small craft can have less than 1.0 comp hull, so you can push the speed up if you want.

I kept it that strong for survivability reasons; seakeeping is maxed out at 50% anyway, nothing more to gain. I know I could have made them a bit faster, but I don't really need to. They can operate with their intended flagship pretty well, so that works in this case.

Quoted

Originally posted by Kaiser KirkDon't know about ASDIC, seems a bunch of nations have it and many don't. No clue as to Siam/ Denmark. RAM indicated the Dutch didn't so until recently I've been installing hydrophones until Phillips Electronics came through for me...

Again, it's one of those things that I'm unsure on due to lack of documentation. Probably Siam didn't have it, but I designed this ship with multi-role in mind. Would simple hydrophones be allowable for Siam? If so, I could easily change it.

Siam might be interested in the Bulgarian 499t design which is currently being built for the Black Sea. I wanted a slightly larger design with about three times the miscellaneous weight. In 1937 I'm also going to build a subchaser/patrol craft on 357t.

Bulgaria currently has empty slip space to build an example for Siam, if desired, and a willingness to sell the design for licensed Siamese home production.

Quoted

Struma, Bulgarian Minesweeper laid down 1935

Displacement:
430 t light; 442 t standard; 499 t normal; 544 t full load

Dimensions: Length overall / water x beam x draught
192.75 ft / 189.00 ft x 27.00 ft x 9.00 ft (normal load)
58.75 m / 57.61 m x 8.23 m x 2.74 m

Armament:
2 - 2.99" / 76.0 mm guns (1x2 guns), 13.39lbs / 6.08kg shells, 1935 Model
Dual purpose guns in deck mount
on centreline forward
2 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.88kg shells, 1935 Model
Quick firing guns in deck mounts
on side, all amidships
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1935 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 31 lbs / 14 kg
Shells per gun, main battery: 150

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.57" / 40 mm - -
2nd: 0.79" / 20 mm - -

Machinery:
Diesel Internal combustion motors,
Direct drive, 2 shafts, 1,098 shp / 819 Kw = 16.00 kts
Range 5,000nm at 12.00 kts
Bunker at max displacement = 101 tons

Complement:
52 - 68

Cost:
£0.115 million / $0.461 million

Distribution of weights at normal displacement:
Armament: 4 tons, 0.8 %
Armour: 5 tons, 1.0 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 5 tons, 1.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 31 tons, 6.3 %
Hull, fittings & equipment: 209 tons, 42.0 %
Fuel, ammunition & stores: 69 tons, 13.9 %
Miscellaneous weights: 180 tons, 36.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,104 lbs / 501 Kg = 82.4 x 3.0 " / 76 mm shells or 0.8 torpedoes
Stability (Unstable if below 1.00): 1.06
Metacentric height 0.8 ft / 0.2 m
Roll period: 12.8 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.06
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.380
Length to Beam Ratio: 7.00 : 1
'Natural speed' for length: 16.50 kts
Power going to wave formation at top speed: 48 %
Trim (Max stability = 0, Max steadiness = 100): 25
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: 14.00 ft / 4.27 m
- Forecastle (20 %): 10.00 ft / 3.05 m
- Mid (50 %): 10.00 ft / 3.05 m
- Quarterdeck (15 %): 10.00 ft / 3.05 m
- Stern: 10.00 ft / 3.05 m
- Average freeboard: 10.32 ft / 3.15 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 66.4 %
- Above water (accommodation/working, high = better): 118.2 %
Waterplane Area: 3,228 Square feet or 300 Square metres
Displacement factor (Displacement / loading): 179 %
Structure weight / hull surface area: 37 lbs/sq ft or 183 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 4.34
- Overall: 1.09
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Ships in class: Struma, Kamchiya, Varbitsa (all building Q3/35, finish Q4/35, working up Q1/36)

Quoted

Salzata, Bulgarian Subchaser laid down 1937

Displacement:
269 t light; 277 t standard; 357 t normal; 422 t full load

Dimensions: Length overall / water x beam x draught
174.75 ft / 174.75 ft x 23.00 ft x 7.50 ft (normal load)
53.26 m / 53.26 m x 7.01 m x 2.29 m

Armament:
2 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1936 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread
2 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on side, all amidships
3 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1936 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 28 lbs / 13 kg
Shells per gun, main battery: 100

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.50" / 13 mm - -
2nd: 0.25" / 6 mm - -
3rd: 0.25" / 6 mm - -

- Conning tower: 0.50" / 13 mm

Machinery:
Diesel Internal combustion motors,
Direct drive, 2 shafts, 2,200 shp / 1,641 Kw = 20.00 kts
Range 6,000nm at 14.00 kts
Bunker at max displacement = 144 tons

Complement:
40 - 53

Cost:
£0.110 million / $0.442 million

Distribution of weights at normal displacement:
Armament: 3 tons, 1.0 %
Armour: 2 tons, 0.6 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 2 tons, 0.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 1 tons, 0.2 %
Machinery: 62 tons, 17.3 %
Hull, fittings & equipment: 147 tons, 41.2 %
Fuel, ammunition & stores: 89 tons, 24.9 %
Miscellaneous weights: 54 tons, 15.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
681 lbs / 309 Kg = 50.5 x 3.0 " / 76 mm shells or 0.6 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 0.7 ft / 0.2 m
Roll period: 11.8 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.10
Seaboat quality (Average = 1.00): 1.42

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.415
Length to Beam Ratio: 7.60 : 1
'Natural speed' for length: 15.63 kts
Power going to wave formation at top speed: 62 %
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: 14.54 ft / 4.43 m
- Forecastle (20 %): 9.25 ft / 2.82 m
- Mid (50 %): 9.25 ft / 2.82 m
- Quarterdeck (15 %): 9.25 ft / 2.82 m
- Stern: 9.25 ft / 2.82 m
- Average freeboard: 9.67 ft / 2.95 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 80.4 %
- Above water (accommodation/working, high = better): 114.2 %
Waterplane Area: 2,592 Square feet or 241 Square metres
Displacement factor (Displacement / loading): 172 %
Structure weight / hull surface area: 31 lbs/sq ft or 150 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.85
- Longitudinal: 4.45
- 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

Ships in class named after the Seven Rila Lakes of Bulgaria

Siam also has a plan for a coastal subchaser and general patrol boat. They are very small... smaller than even Bulgaria's offered design. They will handle the lion's share of the patrolling of Siam's coastline. Carrying 44 depth charges and a small hydrophone array, they would spell trouble for any submarine they encountered.

Quoted

LBP-01, Siamese Partol Boat laid down 1936

Displacement:
160 t light; 168 t standard; 192 t normal; 211 t full load

Dimensions: Length overall / water x beam x draught
162.39 ft / 157.48 ft x 16.40 ft x 6.56 ft (normal load)
49.50 m / 48.00 m x 5.00 m x 2.00 m

Armament:
2 - 3.00" / 76.2 mm guns (1x2 guns), 13.50lbs / 6.12kg shells, 1936 Model
Dual purpose guns in a deck mount with hoist
on centreline forward
12 - 0.79" / 20.0 mm guns (4x3 guns), 0.24lbs / 0.11kg shells, 1936 Model
Dual purpose guns in deck mounts
on side, all amidships, all raised mounts - superfiring
8 - 0.51" / 13.0 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1936 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 30 lbs / 14 kg
Shells per gun, main battery: 200

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.79" / 20 mm 0.79" / 20 mm 0.79" / 20 mm
2nd: 0.79" / 20 mm - -

- Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 1,400 shp / 1,044 Kw = 18.75 kts
Range 3,000nm at 12.55 kts
Bunker at max displacement = 43 tons

Complement:
25 - 33

Cost:
£0.075 million / $0.302 million

Distribution of weights at normal displacement:
Armament: 4 tons, 2.0 %
Armour: 6 tons, 2.9 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 5 tons, 2.6 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 1 tons, 0.3 %
Machinery: 39 tons, 20.5 %
Hull, fittings & equipment: 93 tons, 48.2 %
Fuel, ammunition & stores: 32 tons, 16.5 %
Miscellaneous weights: 19 tons, 9.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
277 lbs / 126 Kg = 20.5 x 3.0 " / 76 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 0.4 ft / 0.1 m
Roll period: 11.0 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.42
Seaboat quality (Average = 1.00): 1.44

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.396
Length to Beam Ratio: 9.60 : 1
'Natural speed' for length: 12.55 kts
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 19.40 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 13.94 ft / 4.25 m
- Forecastle (20 %): 8.20 ft / 2.50 m
- Mid (50 %): 6.56 ft / 2.00 m
- Quarterdeck (15 %): 5.74 ft / 1.75 m
- Stern: 4.92 ft / 1.50 m
- Average freeboard: 7.27 ft / 2.22 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 93.6 %
- Above water (accommodation/working, high = better): 81.3 %
Waterplane Area: 1,587 Square feet or 147 Square metres
Displacement factor (Displacement / loading): 144 %
Structure weight / hull surface area: 28 lbs/sq ft or 137 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.86
- Longitudinal: 4.09
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is cramped
Good seaboat, rides out heavy weather easily

Not exactly 'light' by Siamese terms, but something that I'm thinking about... would be laid down in '36 or '37.

Quoted

Displacement:
3,900 t light; 4,224 t standard; 4,631 t normal; 4,956 t full load

Dimensions: Length overall / water x beam x draught
328.08 ft / 328.08 ft x 60.70 ft x 14.76 ft (normal load)
100.00 m / 100.00 m x 18.50 m x 4.50 m

Armament:
4 - 11.02" / 280 mm guns (2x2 guns), 771.62lbs / 350.00kg shells, 1936 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread
4 - 3.00" / 76.2 mm guns (2x2 guns), 13.23lbs / 6.00kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread, all raised mounts
8 - 3.00" / 76.2 mm guns (4x2 guns), 13.50lbs / 6.12kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on side, all amidships
12 - 1.46" / 37.0 mm guns (6x2 guns), 1.65lbs / 0.75kg shells, 1936 Model
Dual purpose guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 3,267 lbs / 1,482 kg
Shells per gun, main battery: 125

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.91" / 150 mm 164.04 ft / 50.00 m 9.84 ft / 3.00 m
Ends: Unarmoured
Main Belt covers 77 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 5.91" / 150 mm 1.97" / 50 mm 5.91" / 150 mm
2nd: 1.97" / 50 mm 1.97" / 50 mm 1.97" / 50 mm
3rd: 1.97" / 50 mm 1.97" / 50 mm 1.97" / 50 mm
4th: 0.98" / 25 mm - -

- Armour deck: 1.97" / 50 mm, Conning tower: 5.91" / 150 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 4,800 shp / 3,580 Kw = 16.07 kts
Range 4,000nm at 16.07 kts
Bunker at max displacement = 732 tons

Complement:
279 - 364

Cost:
£2.402 million / $9.610 million

Distribution of weights at normal displacement:
Armament: 357 tons, 7.7 %
Armour: 1,278 tons, 27.6 %
- Belts: 456 tons, 9.9 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 280 tons, 6.0 %
- Armour Deck: 507 tons, 10.9 %
- Conning Tower: 35 tons, 0.8 %
Machinery: 135 tons, 2.9 %
Hull, fittings & equipment: 2,080 tons, 44.9 %
Fuel, ammunition & stores: 731 tons, 15.8 %
Miscellaneous weights: 50 tons, 1.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
6,193 lbs / 2,809 Kg = 9.2 x 11.0 " / 280 mm shells or 1.8 torpedoes
Stability (Unstable if below 1.00): 1.18
Metacentric height 3.2 ft / 1.0 m
Roll period: 14.2 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.47
Seaboat quality (Average = 1.00): 1.14

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.551
Length to Beam Ratio: 5.41 : 1
'Natural speed' for length: 18.11 kts
Power going to wave formation at top speed: 44 %
Trim (Max stability = 0, Max steadiness = 100): 61
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: 14.76 ft / 4.50 m
- Forecastle (20 %): 9.84 ft / 3.00 m
- Mid (50 %): 8.20 ft / 2.50 m
- Quarterdeck (20 %): 8.20 ft / 2.50 m
- Stern: 9.02 ft / 2.75 m
- Average freeboard: 9.25 ft / 2.82 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 70.4 %
- Above water (accommodation/working, high = better): 81.8 %
Waterplane Area: 13,914 Square feet or 1,293 Square metres
Displacement factor (Displacement / loading): 104 %
Structure weight / hull surface area: 119 lbs/sq ft or 580 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.71
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is cramped
Ship has slow, easy roll, a good, steady gun platform

Thonburi on steroids. Interesting ship, what do you have in mind for her?

She reminds me more of the OTL Swedish pansarskepps, but slower.

Speaking of which... 16 knots is rather low... I'd advise at least a 20-knot speed just to keep her out of the way of the real battleships. At 16 knots she's just a target

I'd see a 6x8" 21-knot or even 25-knot ship being significantly more useful than this.

Quoted

Originally posted by Brockpaine
She reminds me more of the OTL Swedish pansarskepps, but slower.

She's a stretched copy of Ilmarinen, with more armor, a slightly heavier standard displacement (325t) and a much heavier AA suite.

Quoted

Originally posted by BrockpaineSpeaking of which... 16 knots is rather low... I'd advise at least a 20-knot speed just to keep her out of the way of the real battleships. At 16 knots she's just a target

Ilmarinen had a top speed of 16 knots
Sverige had a top speed of 23 knots.

I was inspired as much by the WW USA's monitors as I was the RL pansarskepps; this partially explains the slower speed and lower seaworthiness. I could try a partial redesign intending to make the ship faster, but I do not wish to get the tonnage up too high. 22 knots is a desirable figure for a CDS design, though it's still insufficient to even 'keep her out of the way of the real battleships'- battleships here are 30 knot affairs these days.

Quoted

Originally posted by BrockpaineI'd see a 6x8" 21-knot or even 25-knot ship being significantly more useful than this.

Why? It would still be in danger of being caught by battleships which could kill it, and would only be a much larger target upon being caught. I have designs for a 24 knot, 2500 ton (light) ship, but she's only armed with 130mm guns and armored against the same.

Bringing back the light craft thread, here's an idea for a 500t (light) AA escort that would be used to escort Siam's coast defense vessels. They aren't as fast as a proper destroyer, but they are loaded down with the heaviest AA guns that Siam has and would be easily produced.

Quoted

Tapi, Siamese Anti-Aircraft Escort laid down 1937

Displacement:
500 t light; 524 t standard; 576 t normal; 618 t full load

Dimensions: Length overall / water x beam x draught
239.52 ft / 229.66 ft x 26.25 ft x 8.20 ft (normal load)
73.00 m / 70.00 m x 8.00 m x 2.50 m

Armament:
4 - 3.00" / 76.2 mm guns in single mounts, 13.23lbs / 6.00kg shells, 1937 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
8 - 1.46" / 37.0 mm guns (4x2 guns), 1.65lbs / 0.75kg shells, 1937 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 66 lbs / 30 kg
Shells per gun, main battery: 300

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm - 1.97" / 50 mm
2nd: 0.98" / 25 mm - -

- Conning tower: 1.97" / 50 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 11,995 shp / 8,948 Kw = 29.05 kts
Range 2,500nm at 15.00 kts
Bunker at max displacement = 95 tons

Complement:
58 - 76

Cost:
£0.335 million / $1.340 million

Distribution of weights at normal displacement:
Armament: 8 tons, 1.4 %
Armour: 17 tons, 3.0 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 14 tons, 2.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.5 %
Machinery: 264 tons, 45.8 %
Hull, fittings & equipment: 210 tons, 36.4 %
Fuel, ammunition & stores: 77 tons, 13.3 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
248 lbs / 112 Kg = 18.3 x 3.0 " / 76 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.21
Metacentric height 1.0 ft / 0.3 m
Roll period: 11.3 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.30
Seaboat quality (Average = 1.00): 0.93

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.408
Length to Beam Ratio: 8.75 : 1
'Natural speed' for length: 17.71 kts
Power going to wave formation at top speed: 71 %
Trim (Max stability = 0, Max steadiness = 100): 54
Bow angle (Positive = bow angles forward): 20.90 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17.22 ft / 5.25 m
- Forecastle (20 %): 13.12 ft / 4.00 m
- Mid (65 %): 11.48 ft / 3.50 m
- Quarterdeck (15 %): 11.48 ft / 3.50 m
- Stern: 11.48 ft / 3.50 m
- Average freeboard: 12.51 ft / 3.81 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 160.5 %
- Above water (accommodation/working, high = better): 153.1 %
Waterplane Area: 3,870 Square feet or 359 Square metres
Displacement factor (Displacement / loading): 77 %
Structure weight / hull surface area: 26 lbs/sq ft or 129 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 3.48
- Overall: 0.61
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Why the emphasis on light AA crafts? They are poor AA plataforms and wast money on something you don't need. If you don't plan on leaving the Gulf of Siam, all you need is lots and lots of fighters. A constant CAP will be a lot more effective and cheaper than a light AA destroyer.

A slow PGB design for fisheries protection and general/ASW patrol duties. The hydrophones and depth charges in the design are oversized and inefficient to reflect their experimental status.

Quoted

Enter ship name, Enter country Enter ship type laid down 1936

Displacement:
350 t light; 369 t standard; 414 t normal; 450 t full load

Dimensions: Length overall / water x beam x draught
173.88 ft / 173.88 ft x 24.61 ft x 8.20 ft (normal load)
53.00 m / 53.00 m x 7.50 m x 2.50 m

Armament:
2 - 3.94" / 100 mm guns in single mounts, 33.07lbs / 15.00kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.65lbs / 0.75kg shells, 1936 Model
Dual purpose guns in deck mounts
on side, all amidships
6 - 0.51" / 13.0 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1936 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 73 lbs / 33 kg
Shells per gun, main battery: 250

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.57" / 40 mm - 1.57" / 40 mm
2nd: 0.98" / 25 mm - -

- Conning tower: 1.57" / 40 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 3,000 shp / 2,238 Kw = 20.05 kts
Range 4,000nm at 12.00 kts
Bunker at max displacement = 81 tons

Complement:
45 - 59

Cost:
£0.164 million / $0.656 million

Distribution of weights at normal displacement:
Armament: 8 tons, 2.0 %
Armour: 11 tons, 2.7 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 9 tons, 2.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.5 %
Machinery: 84 tons, 20.3 %
Hull, fittings & equipment: 213 tons, 51.4 %
Fuel, ammunition & stores: 64 tons, 15.6 %
Miscellaneous weights: 33 tons, 8.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
737 lbs / 334 Kg = 24.1 x 3.9 " / 100 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 0.8 ft / 0.2 m
Roll period: 11.8 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.38
Seaboat quality (Average = 1.00): 1.67

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.413
Length to Beam Ratio: 7.07 : 1
'Natural speed' for length: 13.19 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 30
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: 15.58 ft / 4.75 m
- Forecastle (20 %): 12.30 ft / 3.75 m
- Mid (50 %): 11.48 ft / 3.50 m
- Quarterdeck (15 %): 10.66 ft / 3.25 m
- Stern: 9.84 ft / 3.00 m
- Average freeboard: 11.70 ft / 3.57 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 92.2 %
- Above water (accommodation/working, high = better): 128.7 %
Waterplane Area: 2,655 Square feet or 247 Square metres
Displacement factor (Displacement / loading): 148 %
Structure weight / hull surface area: 38 lbs/sq ft or 184 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.79
- Longitudinal: 8.42
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

33t - Misc. Weight
-------------------------
15t - Hydrophone array
10t - 40 depth charges (225kg each)
8t - small brig (5 man capacity)

Quoted

Originally posted by Carthaginian
A slow PGB design for fisheries protection and general/ASW patrol duties. The hydrophones and depth charges in the design are oversized and inefficient to reflect their experimental status.

If you're trying 'homegrown' designs that might make sense, otherwise you have friends with first line gear

RA once noted on one of my small designs that a bow in the 6m range is useful for most seas, regardless of seaboat rating. May not be needed for the south china sea, but likely doesn't hurt anything to have a rise at the bow.

Other than that, looks pretty good.

Quoted

Originally posted by Kaiser Kirk

Quoted

Originally posted by Carthaginian
The hydrophones and depth charges in the design are oversized and inefficient to reflect their experimental status.

If you're trying 'homegrown' designs that might make sense, otherwise you have friends with first line gear

Well, Siam likes those friends, and would keep them.
Thus, our second-line ships feature second-line gear- home-made copies of the Dutch equipment- in order to keep from over stressing our suppliers. I do have a request for 6 new advanced hydrophone units to be delivered in 1936, so I can affix them to the new destroyers that I'm purchasing from the US. With the addition of first-rate hydrophones, the Caldwell class will be fine general purpose destroyers.

Quoted

Originally posted by Kaiser KirkRA once noted on one of my small designs that a bow in the 6m range is useful for most seas, regardless of seaboat rating. May not be needed for the south china sea, but likely doesn't hurt anything to have a rise at the bow.

Well, to get to 6m, I'd have to limit my over-the-prow firing to long ranges. The flush-deck design just seemed simpler to design and construct. I think it'll be adequate for it's intended task.

Quoted

Originally posted by Kaiser KirkOther than that, looks pretty good.

Thanks!

I decided that I didn't like the prior light destroyer that I posted here... primarily because after careful consideration, I decided that it wasn't going to have the necessary deckspace to hold what I wanted to to. So, here's a revised version of the ship.

Deciding that the 330 ton Surasdra class torpedo boats were too light to be used in fleet duties, the Royal Siamese Navy put forth a call for a design that could actually serve as a blue-water escort for Siamese capital ships. The result is the Bang Pa Kong class light destroyer. Though smaller and slower than many destroyers fielded by other nation, the Bang Pa Kong more than meets the needs of Siam.

Her main guns are dual purpose 100mm guns derived from the Maeklong's anti-aircraft battery, arranged with one mount forward and two aft. A quartet of 37mm AA mounts are also mounted to protect the ship and whatever it's escorting from enemy aircraft. Finally, a quintuple torpedo mount, armed with 500mm torpedoes, provides striking power against large vessels.



Bang Pa Kong, Siamese Coastal Destroyer laid down 1936

Displacement:
815 t light; 851 t standard; 980 t normal; 1,084 t full load

Dimensions: Length overall / water x beam x draught
285.45 ft / 275.59 ft x 27.07 ft x 11.48 ft (normal load)
87.00 m / 84.00 m x 8.25 m x 3.50 m

Armament:
3 - 3.94" / 100 mm guns in single mounts, 30.86lbs / 14.00kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority aft, 1 raised mount aft
8 - 1.46" / 37.0 mm guns (4x2 guns), 1.65lbs / 0.75kg shells, 1936 Model
Dual purpose guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 106 lbs / 48 kg
Shells per gun, main battery: 250
5 - 19.7" / 500 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.57" / 40 mm 0.39" / 10 mm 1.57" / 40 mm
2nd: 1.57" / 40 mm - -

- Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 20,000 shp / 14,920 Kw = 31.06 kts
Range 4,500nm at 15.00 kts
Bunker at max displacement = 233 tons

Complement:
86 - 113

Cost:
£0.546 million / $2.182 million

Distribution of weights at normal displacement:
Armament: 13 tons, 1.3 %
Armour: 17 tons, 1.8 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 14 tons, 1.4 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.3 %
Machinery: 457 tons, 46.7 %
Hull, fittings & equipment: 307 tons, 31.3 %
Fuel, ammunition & stores: 165 tons, 16.8 %
Miscellaneous weights: 20 tons, 2.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
320 lbs / 145 Kg = 10.5 x 3.9 " / 100 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 0.9 ft / 0.3 m
Roll period: 12.2 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.42
Seaboat quality (Average = 1.00): 1.03

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.400
Length to Beam Ratio: 10.18 : 1
'Natural speed' for length: 19.17 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 68
Bow angle (Positive = bow angles forward): 26.60 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 %): 18.04 ft / 5.50 m
- Mid (50 %): 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: 13.01 ft / 3.97 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 164.0 %
- Above water (accommodation/working, high = better): 77.6 %
Waterplane Area: 4,766 Square feet or 443 Square metres
Displacement factor (Displacement / loading): 78 %
Structure weight / hull surface area: 29 lbs/sq ft or 143 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.51
- Longitudinal: 2.96
- Overall: 0.61
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


20t - Misc. Weight
-------------------------
8t - Hydrophone array
4t - Depth charges
8t - 5 x 500mm torpedoes

Not a bad design considering Siams limited resources. How many will be build?

Quoted

Originally posted by HoOmAn
Not a bad design considering Siams limited resources. How many will be build?

I'm planning at least one 6-unit production run for 1937. Further ships could be possible during 1938. I would need to contract some dock space from a willing nation to build 3 of the units, however, as Siam only has 3 drydocks capable of holding ships of this size.

Unfortunately, you can only do so much with a Type 0 drydock.

Quoted

Originally posted by Carthaginian

Quoted

Originally posted by HoOmAn
Not a bad design considering Siams limited resources. How many will be build?

I'm planning at least one 6-unit production run for 1937. Further ships could be possible during 1938. I would need to contract some dock space from a willing nation to build 3 of the units, however, as Siam only has 3 drydocks capable of holding ships of this size.

Unfortunately, you can only do so much with a Type 0 drydock.

In 1937 I left a space in my program for buying used vessels, so I have three quarters with only one ship on the slips (on a D1). I'll essentially have one Type 2, three Type 1s, and 4 Type 0s available. If I don't have any purchase deals in the works by Q1/37, I'll either start a pair of DDs or a series of minesweepers in Q2: if Siam would like to use the empty spaces, tell me in Q1 before I start building.

Australia will have a bunch of Type 1 Docks/Slips available. If you need to use them just ask.