WesWorld

Siam has recently purchased the six Caldwell class destroyers from the United States and has decided to modernize them for fleet use. They would serve as main-line units for the Siamese Navy for at least 10 years, so I feel that this rather extensive refit is justified.

First, the ships will be taken into drydock and will have their engines gutted and replaced by modern units. Their old breech loading 4"/L50 deck guns would be replaced by new dual-purpose 100mm/L45 in mounts and hoists on a 1:1 basis. The aft pair of triple 533mm torpedo mounts would be removed, and 4 twin 37mm AA guns would be installed in their place. Finally, they would be equipped with hydrophone arrays purchased from the Dutch and a large complement of depth charges for ASW duties.

Siam would refurbish these ships during 1936, and would do 3 at the time. The entire class would be back in service by the end of the first quarter of 1937.

Quoted

Chao Phya (ex-Caldwell), Siamese Destroyer laid down 1916 (Engine 1936)

Displacement:
1,100 t light; 1,154 t standard; 1,345 t normal; 1,497 t full load

Dimensions: Length overall / water x beam x draught
315.49 ft / 314.00 ft x 31.10 ft x 9.50 ft (normal load)
96.16 m / 95.71 m x 9.48 m x 2.90 m

Armament:
2 - 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, evenly spread
2 - 3.94" / 100 mm guns in single mounts, 30.86lbs / 14.00kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on side, all amidships
8 - 1.46" / 37.0 mm guns (4x2 guns), 1.65lbs / 0.75kg shells, 1916 Model
Breech loading guns in deck mounts
on side, evenly spread
8 - 0.51" / 13.0 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1916 Model
Breech loading guns in deck mounts
on side, evenly spread, 4 raised mounts
Weight of broadside 137 lbs / 62 kg
Shells per gun, main battery: 300
6 - 21.0" / 533 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 0.39" / 10 mm 1.57" / 40 mm
3rd: 0.98" / 25 mm - -
4th: 0.59" / 15 mm - -

- Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 26,000 shp / 19,396 Kw = 30.21 kts
Range 2,360nm at 20.00 kts
Bunker at max displacement = 343 tons

Complement:
110 - 144

Cost:
£0.230 million / $0.921 million

Distribution of weights at normal displacement:
Armament: 17 tons, 1.3 %
Armour: 19 tons, 1.4 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 15 tons, 1.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 4 tons, 0.3 %
Machinery: 629 tons, 46.8 %
Hull, fittings & equipment: 401 tons, 29.8 %
Fuel, ammunition & stores: 245 tons, 18.2 %
Miscellaneous weights: 35 tons, 2.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
487 lbs / 221 Kg = 16.0 x 3.9 " / 100 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.24
Metacentric height 1.3 ft / 0.4 m
Roll period: 11.6 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.30
Seaboat quality (Average = 1.00): 1.03

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.507
Length to Beam Ratio: 10.10 : 1
'Natural speed' for length: 17.72 kts
Power going to wave formation at top speed: 68 %
Trim (Max stability = 0, Max steadiness = 100): 68
Bow angle (Positive = bow angles forward): 5.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17.00 ft / 5.18 m
- Forecastle (20 %): 16.00 ft / 4.88 m
- Mid (50 %): 14.00 ft / 4.27 m
- Quarterdeck (15 %): 12.00 ft / 3.66 m
- Stern: 10.00 ft / 3.05 m
- Average freeboard: 13.98 ft / 4.26 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 164.8 %
- Above water (accommodation/working, high = better): 91.2 %
Waterplane Area: 6,551 Square feet or 609 Square metres
Displacement factor (Displacement / loading): 82 %
Structure weight / hull surface area: 32 lbs/sq ft or 154 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.53
- Longitudinal: 1.94
- Overall: 0.60
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform

So, does anyone think it would be worth this:
25% refit
275 tons per ship
2.5 months for refit

I traditionally complain about high cruising speeds leading to higher peacetime consumption and additional supply line burdens, which mostly is ignored.
Otherwise,
Looks like a pretty decent refit to me.

Not bad, Mexico however skipped on the engine upgrade. It's probably not worth it, for the speed gained. Money saved can then be spent buying some nice, 'like new', Australian Patrol Boats in great condition.

Quoted

Originally posted by Kaiser Kirk
I traditionally complain about high cruising speeds leading to higher peacetime consumption and additional supply line burdens, which mostly is ignored.
Otherwise,
Looks like a pretty decent refit to me.

Well, that's a 'wartime cruising speed.'
During peacetime, they would only cruise at about 10-12 knots, meaning that their range would be much, much longer. In reality, their peacetime patrols would be limited more by the amount of food carried aboard than fuel.

Quoted

Originally posted by Desertfox
Not bad, Mexico however skipped on the engine upgrade. It's probably not worth it, for the speed gained. Money saved can then be spent buying some nice, 'like new', Australian Patrol Boats in great condition.

There were two reasons for the engine replacement:
1.) OoC Reason - adding 'mount & hoist' guns was a 25% refit, as was an engine replacement. Since I had to go that far to get the guns I wanted aboard, I decided to go ahead and replace the engines.
2.) IC Reason - to provide enough room for the new amidships gun arrangement, the engine spaces had to be reduced. As a reduction in speed was viewed as intolerable, the Admiralty decided to replace the engines with more modern units to both preserve speed and provide adequate room for the guns.

engines is 50%

Doh missed the rule change,

Its 25%!

Myself, I'd be a bit wary of reducing the ship's primary weapons (her torpedoes) by 50%. I'd probably try to keep all 4 torpedo banks, and probably settle for only 3 100mm guns, all on the centerline.

Quoted

Originally posted by Hrolf Hakonson
Myself, I'd be a bit wary of reducing the ship's primary weapons (her torpedoes) by 50%. I'd probably try to keep all 4 torpedo banks, and probably settle for only 3 100mm guns, all on the centerline.

Well, I did that because these ships are now going to serve primarily as fleet escorts/screening vessels. I can build lighter, more expendable ships for concentrated torpedo attacks if necessary (and am indeed planning on doing so). Does that line of reasoning make good sense?

Quoted

Originally posted by Carthaginian

Quoted

Originally posted by Hrolf Hakonson
Myself, I'd be a bit wary of reducing the ship's primary weapons (her torpedoes) by 50%. I'd probably try to keep all 4 torpedo banks, and probably settle for only 3 100mm guns, all on the centerline.

Well, I did that because these ships are now going to serve primarily as fleet escorts/screening vessels. I can build lighter, more expendable ships for concentrated torpedo attacks if necessary (and am indeed planning on doing so). Does that line of reasoning make good sense?

The question I'd have, then, is screening how, and if gunfire is rated more highly than torpedoes, why is the current design limited by having half of it's mounts on the sides, where 1 of them probably can't be used at any given time. The idea I had gives you the same number of effective guns, but keeps more torpedoes for use against anything of any size.

Well, for the multi-purpose screening role (against aircraft, other DD's and MTB's as much as for attacking cruisers) I felt that guns were more important than torps. These would be large, important ships to the Siamese. I wouldn't want them trying to do torpedo attacks when I could easily build smaller ships that are more expendable to do the same thing.

Out of curiosity, do you think that the deck is wide enough for a twin gunhouse? if that's a possibility, I'd just reduce it to two twin mount & hoists and keep the torps the same.

What are you going to be screening? You already got rid of half your fleet.

Quoted

Originally posted by Desertfox
What are you going to be screening? You already got rid of half your fleet.

Give the guy a chance!
YOU can't be the only one one here with crazy fleet plans!!

Quoted

Originally posted by Carthaginian
Out of curiosity, do you think that the deck is wide enough for a twin gunhouse? if that's a possibility, I'd just reduce it to two twin mount & hoists and keep the torps the same.

Take a look here to see how much room the Caldwell's (USS Stockton in particular) had forward: http://www.navweaps.com/Weapons/WNUS_4-50_mk9_pics.htm She DID mount a twin 4" forward, but there's no extra room at all.

Here's the final version of my Caldwell refit. The rotating enclosed mount will help deal with the lack of deckspace for loading the twin 100mm guns; though the mounts will have to be well-balanced, and the ship will probably have some problems in heeling over if the guns are firing abeam while turning. Other than that, I think she looks nice...

Any comments- good or bad?



Chao Phya (ex-Caldwell), Siamese Destroyer laid down 1916 (Engine 1936)

Displacement:
1,100 t light; 1,151 t standard; 1,341 t normal; 1,493 t full load

Dimensions: Length overall / water x beam x draught
315.49 ft / 314.00 ft x 31.10 ft x 9.50 ft (normal load)
96.16 m / 95.71 m x 9.48 m x 2.90 m

Armament:
4 - 3.94" / 100 mm guns (2x2 guns), 30.86lbs / 14.00kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread
8 - 1.46" / 37.0 mm guns (4x2 guns), 1.55lbs / 0.70kg shells, 1936 Model
Dual purpose guns in deck mounts
on side, evenly spread, all raised mounts
8 - 0.51" / 13.0 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1916 Model
Machine guns in deck mounts
on side, evenly spread, 4 raised mounts
Weight of broadside 136 lbs / 62 kg
Shells per gun, main battery: 300
8 - 21.0" / 533 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: 0.98" / 25 mm - -
3rd: 0.59" / 15 mm - -

- Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 26,000 shp / 19,396 Kw = 30.22 kts
Range 5,080nm at 15.00 kts
Bunker at max displacement = 342 tons

Complement:
110 - 144

Cost:
£0.230 million / $0.920 million

Distribution of weights at normal displacement:
Armament: 17 tons, 1.3 %
Armour: 17 tons, 1.3 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 13 tons, 1.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 4 tons, 0.3 %
Machinery: 628 tons, 46.8 %
Hull, fittings & equipment: 402 tons, 30.0 %
Fuel, ammunition & stores: 241 tons, 18.0 %
Miscellaneous weights: 36 tons, 2.7 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
479 lbs / 217 Kg = 15.7 x 3.9 " / 100 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric height 1.2 ft / 0.4 m
Roll period: 11.9 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.32
Seaboat quality (Average = 1.00): 1.02

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.506
Length to Beam Ratio: 10.10 : 1
'Natural speed' for length: 17.72 kts
Power going to wave formation at top speed: 68 %
Trim (Max stability = 0, Max steadiness = 100): 69
Bow angle (Positive = bow angles forward): 5.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17.00 ft / 5.18 m
- Forecastle (20 %): 16.00 ft / 4.88 m
- Mid (50 %): 14.00 ft / 4.27 m
- Quarterdeck (15 %): 12.00 ft / 3.66 m
- Stern: 10.00 ft / 3.05 m
- Average freeboard: 13.98 ft / 4.26 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 164.8 %
- Above water (accommodation/working, high = better): 68.8 %
Waterplane Area: 6,542 Square feet or 608 Square metres
Displacement factor (Displacement / loading): 81 %
Structure weight / hull surface area: 32 lbs/sq ft or 155 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.53
- Longitudinal: 1.96
- Overall: 0.60
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

25% for refit
275 tons per ship
825 tons each for group 1 & 2
2.5 months for refit