WesWorld

This ship is based on the RL Japanese Yubari, which I stumbled across while browsing through my Jane's WW2.

IIRC, ships 3,000 tons and under can go down to 0.50 strength, correct?

The splinter-armour only covers the engineering spaces...

Gun arrangement:

--1-2-----*--1--
[SIZE=1](* - 100mm)[/SIZE]

CL29, laid down 1929

Length, 435 ft x Beam, 39.5 ft x Depth, 12.0 ft
3004 tons normal displacement (2808 tons standard)

Main battery: 4 x 6.00-inch / 152mm
Secondary battery: 1 x 3.94-inch / 100mm
AA battery: 3 x 0.98-inch / 25mm
Light battery: 2 x 0.54-inch / 13.7mm

Weight of broadside: 486 lbs

4 TT, 24.0"

Main belt, 1.18 inches; ends unarmored
Armor deck, average 0.79 inches
C.T., 1.18 inches

Battery armor:
Main, 1.57" shields / secondary, 1.18" shields
AA, 0.54" shields

Maximum speed for 51978 shp = 33.00 knots
Approximate cruising radius, 5000 nm / 12 kts

Typical complement: 203-264


Estimated cost, $5.500 million (£1.375 million)

Remarks:

Caution: Hull structure is subject to strain in open-sea
conditions.

Relative extent of belt armor, 160 percent of 'typical' coverage.

Main belt does not fully protect magazines and
engineering spaces.

Poor seaboat, wet and uncomfortable; reduced performance
in heavy weather.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.

Roomy upper decks; superior accommodation and working space.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 61 tons = 2 pct
Armor, total ..................... 343 tons = 11 pct

Belt 164 tons = 5 pct
Deck 160 tons = 5 pct
C.T. 5 tons = 0 pct
Armament 14 tons = 0 pct

Machinery ........................ 1414 tons = 47 pct
Hull and fittings; equipment ..... 840 tons = 28 pct
Fuel, ammunition, stores ......... 297 tons = 10 pct
Miscellaneous weights ............ 50 tons = 2 pct
-----
3004 tons = 100 pct

Estimated metacentric height, 2.0 ft

Displacement summary:

Light ship: 2707 tons
Standard displacement: 2808 tons
Normal service: 3004 tons
Full load: 3150 tons

Loading submergence 313 tons/foot

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.32

Shellfire needed to sink: 967 lbs = 8.5 x 6.1-inch shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.4
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 51 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.18

Relative quality as a seaboat: 0.75

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.51
Sharpness coefficient: 0.32
Hull speed coefficient 'M' = 9.22
'Natural speed' for length = 20.9 knots
Power going to wave formation
at top speed: 63 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 169 percent

Relative accommodation and working space: 123 percent


Displacement factor: 74 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.66
(Structure weight per square
foot of hull surface: 47 lbs)

Relative longitudinal hull strength: 0.76
(for 13.5 ft average freeboard;
freeboard adjustment +1.6 ft)

Relative composite hull strength: 0.67

+++++++++++++++++++++++++

CL29 Mk.2, laid down 1929

Length, 435 ft x Beam, 39.5 ft x Depth, 12.0 ft
3004 tons normal displacement (2791 tons standard)

Main battery: 4 x 6.00-inch / 152mm
Secondary battery: 2 x 3.94-inch / 100mm
AA battery: 3 x 0.98-inch / 25mm
Light battery: 2 x 0.54-inch / 13.7mm

Weight of broadside: 517 lbs

4 TT, 24.0"

Main belt, 1.18 inches; ends unarmored
Armor deck, average 0.79 inches
C.T., 1.18 inches

Battery armor:
Main, 1.57" shields / secondary, 1.18" shields
AA, 0.54" shields

Maximum speed for 51978 shp = 33.00 knots
Approximate cruising radius, 5400 nm / 12 kts

Typical complement: 203-264


Estimated cost, $5.538 million (£1.385 million)

Remarks:

Caution: Hull structure is subject to strain in open-sea
conditions.

Relative extent of belt armor, 160 percent of 'typical' coverage.

Main belt does not fully protect magazines and
engineering spaces.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.

Roomy upper decks; superior accommodation and working space.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 65 tons = 2 pct
Armor, total ..................... 346 tons = 12 pct

Belt 164 tons = 5 pct
Deck 160 tons = 5 pct
C.T. 5 tons = 0 pct
Armament 17 tons = 1 pct

Machinery ........................ 1413 tons = 47 pct
Hull and fittings; equipment ..... 840 tons = 28 pct
Fuel, ammunition, stores ......... 316 tons = 11 pct
Miscellaneous weights ............ 25 tons = 1 pct
-----
3004 tons = 100 pct

Estimated metacentric height, 2.3 ft

Displacement summary:

Light ship: 2688 tons
Standard displacement: 2791 tons
Normal service: 3004 tons
Full load: 3163 tons

Loading submergence 313 tons/foot

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.44

Shellfire needed to sink: 1029 lbs = 9.1 x 6.1-inch shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.4
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 50 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.20

Relative quality as a seaboat: 1.01

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.51
Sharpness coefficient: 0.32
Hull speed coefficient 'M' = 9.22
'Natural speed' for length = 20.9 knots
Power going to wave formation
at top speed: 63 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 169 percent

Relative accommodation and working space: 143 percent


Displacement factor: 74 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.60
(Structure weight per square
foot of hull surface: 45 lbs)

Relative longitudinal hull strength: 0.90
(for 15.7 ft average freeboard;
freeboard adjustment +3.8 ft)

Relative composite hull strength: 0.62

+++++++++++++++++++++++++

This one, looks much better than the first version, nice speed, and quite a powerful punch... however a couple nitpicks.

- Do you really think that just 4 main guns are enough? If this is a Yubari clone, why don´t you adopt a smaller gun size (Yubari had 5.5) but in greater number?.

- Drop the conning tower, I don´t think it´s worth the tonnage in a ship this size.

Overall looks quite good, good job.

I second Gravina´s comments.

Further note that YUBARI is listed a tid bit heavier in general. Whitley for example has her as 2890ts or 2936t standard. On such a small design ever ton counts so making her heavier might help.

Your designs range also is larger than YUBARIs (5500nm at 10kn), might save some stress to her hull.

You also put more armor on her. Not a bad idea but might save you weight otherwise.

Why save weight? Yours is much slower than YUBARI was and 33kn might not be enough to escape a real CL which will always make micemeat out of your mini-CL.

Anyway, I know how difficult it is to get a decent small fast combatant outta SS... So keep it coming!

Quoted

- Do you really think that just 4 main guns are enough? If this is a Yubari clone, why don´t you adopt a smaller gun size (Yubari had 5.5) but in greater number?.

Well, my main destroyer class will have 4 x 130mm, so I wanted the extra punch. I'll try 6 x 130...

Quoted

Your designs range also is larger than YUBARIs (5500nm at 10kn), might save some stress to her hull.

Do you mean the added range helps the hull strength, or that reducing range would help?

As for armour, I'm considering ditching the belt and going with deck armour only...

I'll see what I can scare up and post the results later.

...after wrestling with SS for an hour, I can't achieve any real improvement. So (for now) it stays as-is.

Quoted

33kn might not be enough to escape a real CL which will always make micemeat out of your mini-CL.

At which point the 9 destroyers my CL was leading make mincemeat out of the other CL.

Tweaked some more. Replaced the twin 100mm AA with another 6"; among other things this seems more realistic for the time period...

Fore-to-aft layout is:
Single 6"
Twin 6"
(superstructure)
Twin TT
Triple 25mm
Twin TT
Single 6"
Single 6"

Filipino Mindanao-class light cruiser, laid down 1929

Length, 435 ft x Beam, 39.5 ft x Depth, 12.0 ft
3004 tons normal displacement (2792 tons standard)

Main battery: 5 x 6.00-inch / 152mm
AA battery: 3 x 0.98-inch / 25mm
Light battery: 2 x 0.54-inch / 13.7mm

Weight of broadside: 569 lbs

4 TT, 24.0"

Main belt, 1.18 inches; ends unarmored
Armor deck, average 0.79 inches

Battery armor:
Main, 1.57" shields
AA, 0.54" shields

Maximum speed for 51978 shp = 33.00 knots
Approximate cruising radius, 5400 nm / 12 kts

Typical complement: 203-264


Estimated cost, $5.611 million (£1.403 million)

Remarks:

Caution: Hull structure is subject to strain in open-sea
conditions.

Relative extent of belt armor, 160 percent of 'typical' coverage.

Main belt does not fully protect magazines and
engineering spaces.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.

Roomy upper decks; superior accommodation and working space.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 71 tons = 2 pct
Armor, total ..................... 341 tons = 11 pct

Belt 164 tons = 5 pct
Deck 160 tons = 5 pct
Armament 17 tons = 1 pct

Machinery ........................ 1407 tons = 47 pct
Hull and fittings; equipment ..... 845 tons = 28 pct
Fuel, ammunition, stores ......... 320 tons = 11 pct
Miscellaneous weights ............ 20 tons = 1 pct
-----
3004 tons = 100 pct

Estimated metacentric height, 2.3 ft

Displacement summary:

Light ship: 2684 tons
Standard displacement: 2792 tons
Normal service: 3004 tons
Full load: 3163 tons

Loading submergence 313 tons/foot

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.44

Shellfire needed to sink: 1014 lbs = 8.9 x 6.1-inch shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.4
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 50 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.22

Relative quality as a seaboat: 1.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.51
Sharpness coefficient: 0.32
Hull speed coefficient 'M' = 9.22
'Natural speed' for length = 20.9 knots
Power going to wave formation
at top speed: 63 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 170 percent

Relative accommodation and working space: 143 percent


Displacement factor: 73 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.59
(Structure weight per square
foot of hull surface: 45 lbs)

Relative longitudinal hull strength: 0.89
(for 15.6 ft average freeboard;
freeboard adjustment +3.7 ft)

Relative composite hull strength: 0.62

She´s quite fast, well armed, she reminds me of some of the smaller CLs I´ve in service, though faster than them.

Good job.

I decided to change the 5 x 6" to 8 x 130mm, which also allowed me to add the four 57mm guns...

Filipino Babuyan-class minelaying cruiser/destroyer leader, laid down 1929

Length, 435 ft x Beam, 39.5 ft x Depth, 12.0 ft
3004 tons normal displacement (2787 tons standard)

Main battery: 8 x 5.10-inch / 130mm (4 x 2)
Quick firing guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
Secondary battery: 4 x 2.24-inch / 57mm (4 x 1)
Dual purpose guns in deck mounts
on side ends, evenly spread
AA battery: 3 x 0.98-inch / 25mm (1 x 3)
Anti-aircraft guns in a deck mount
on centreline, aft, raised mount - superfiring
Light battery: 2 x 0.54-inch / 13.7mm (2 x 1)
Machine guns in deck mounts
on side, all amidships, all raised mounts

Weight of broadside: 586 lbs

Mines: 24 x 1,000-lb mines

4 TT, 24.0"

Main belt, 1.18 inches; ends unarmored
Armor deck, average 0.8 inches

Battery armor:
Main, 1.57" shields / secondary, 0.98" shields
AA, 0.54" shields

Maximum speed for 52004 shp = 33.00 knots
Approximate cruising radius, 5500 nm / 12 kts

Typical complement: 203-264


Estimated cost, $5.596 million (£1.399 million)

Remarks:

Caution: Hull structure is subject to strain in open-sea
conditions.

Relative extent of belt armor, 160 percent of 'typical' coverage.

Main belt does not fully protect magazines and
engineering spaces.

Ship has slow, easy roll; a good, steady gun platform.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.

Roomy upper decks; superior accommodation and working space.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 70 tons = 2 pct
Armor, total ..................... 348 tons = 12 pct

Belt 164 tons = 5 pct
Deck 160 tons = 5 pct
Armament 25 tons = 1 pct

Machinery ........................ 1408 tons = 47 pct
Hull and fittings; equipment ..... 835 tons = 28 pct
Fuel, ammunition, stores ......... 324 tons = 11 pct
Miscellaneous weights ............ 20 tons = 1 pct
-----
3004 tons = 100 pct

Estimated metacentric height, 1.8 ft

Displacement summary:

Light ship: 2680 tons
Standard displacement: 2787 tons
Normal service: 3004 tons
Full load: 3166 tons

Loading submergence 313 tons/foot

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.24

Shellfire needed to sink: 932 lbs = 13.9 x 5.1-inch shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.4
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 70 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.30

Relative quality as a seaboat: 1.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.51
Sharpness coefficient: 0.32
Hull speed coefficient 'M' = 9.22
'Natural speed' for length = 20.9 knots
Power going to wave formation
at top speed: 63 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 170 percent

Relative accommodation and working space: 144 percent


Displacement factor: 73 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.59
(Structure weight per square
foot of hull surface: 44 lbs)

Relative longitudinal hull strength: 0.87
(for 15.8 ft average freeboard;
freeboard adjustment +3.8 ft)

Relative composite hull strength: 0.61

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

435.00 x 39.50 x 12.00; 15.75 -- Dimensions
0.51 -- Block coefficient
1929 -- Year laid down
33.00 / 5500 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
20 tons -- Miscellaneous weights
++++++++++
8 x 5.12; 0 -- Main battery; turrets
Gun-shields
:
4 x 2.24; 0 -- Secondary battery; turrets
Gun-shields
:
3 x 0.98 -- Tertiary (QF/AA) battery
Gun-shields
:
2 x 0.54 -- Fourth (light) battery
4 / 0 / 24.00 -- TT / submerged / size
++++++++++
1.18 / 0.00 / 0.00 / 0.00; 160 -- Belt armor; relative extent
0.79 / 0.00 -- Deck / CT
1.57 / 0.98 / 0.54 / 0.00 -- Battery armor


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

Try super emposing the single mount instead of the twin, this should improve stability, albeit likely a miniscule ammount.

I think she's too slow. 33knts is fairly poor for a destroyer leader. My Italian Condottieri I can do 34knts and they are 6.000t ships.

I'd go for a block coefficient of around 0.4 - 0.45 and try and get up to 34-35knts at least.

Quoted

I think she's too slow. 33knts is fairly poor for a destroyer leader. My Italian Condottieri I can do 34knts and they are 6.000t ships.

Might be so, but why are you comparing his 3000 ton ship with your 6000 ton ship? I might as well say "My Dairen design can do 34 knots and that one is a 30,000 ton design."
And be honest, I cannot compare the Dairen to either the Babuyan or the Condottieri I since it is about 10 times bigger than the Babuyan and 5 times bigger than the Condottieri I.
I think that it is slightly easier to get a 6,000 ton vessel with armor to 34 knots than a 3000 ton vessel with armor to 34 knots.
But still, I do agree that you should be able to get more out of that design.
I really think it is rather pointless to compare the Babuyan with the Condottieri I especially since the Condottieri I has a 19+foot draft!! I have noticed over the time that I use Springstyle and Springsharp, that when you change any part of a ships dimension (length, beam, draft or BC) a bigger draft results in more hullstrength gained while gaining the fewest number of tons to your displacement.

Can I sell you this ?

A 34-36kt DD would probably only be able to outstrip a 33kt leader in calm sea, otherwise the bigger ship has an advantage, especially if it has good sea keeping.

Quoted

My Italian Condottieri I can do 34knts and they are 6.000t ships

Big and expensive for a leader. What is wrong with Capt. Romani as a model? Or a Tashkent.

Cheers,

I was going mainly for the point that the smaller ship can use 0.5 hull strength instead of 0.75+

Quoted

I was going mainly for the point that the smaller ship can use 0.5 hull strength instead of 0.75+

Does that give a 3000 ton design an advantage over a 6000 tons design, especially when the 6,000 ton design uses a transom stern and a draft of 19+ feet?
When I take Swamphen's design and change the draft from 12 to 19 feet, the ship gains about 1600 tons and hull strength increases by about 0.70. If I change any of the other dimensions to get an increase of 1600 tons, I won't get as much hull strength points as with draft. Don't you agree that 0.70 is a lot more than 0.25? (that's a +0.45 point advantage your ship has with the increased draft)
I don't think a smaller ship has any advantage at all over a 6000 ton ship by being able to use a hull strength of as low as 0.5.
For the Babuyan adding a transom stern and adjusting the freeboard slightly is enough to get that vessel up to 34 knots (hope I made no errors anywhere):

Babuyan, Filipino Destroyer leader laid down 1929

Displacement:
2,685 t light; 2,793 t standard; 3,004 t normal; 3,162 t full load

Dimensions: Length overall / water x beam x draught
435.00 ft / 435.00 ft x 39.50 ft x 12.00 ft (normal load)
132.59 m / 132.59 m x 12.04 m x 3.66 m

Armament:
8 - 5.12" / 130 mm guns (4x2 guns), 67.03lbs / 30.40kg shells, 1929 Model
Quick firing guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 2.24" / 57.0 mm guns in single mounts, 5.65lbs / 2.56kg shells, 1929 Model
Dual purpose guns in deck mounts
on side ends, evenly spread
3 - 0.98" / 25.0 mm guns (1x3 guns), 0.48lbs / 0.22kg shells, 1929 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
2 - 0.54" / 13.7 mm guns in single mounts, 0.08lbs / 0.04kg shells, 1929 Model
Machine guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 560 lbs / 254 kg
Shells per gun, main battery: 150
4 - 24.0" / 609.6 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1.18" / 30 mm 435.00 ft / 132.59 m 7.54 ft / 2.30 m
Ends: Unarmoured
Main Belt covers 154 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.57" / 40 mm - 1.00" / 25 mm
2nd: 0.98" / 25 mm - -
3rd: 0.54" / 14 mm - -

- Armour deck: 0.80" / 20 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 50,583 shp / 37,735 Kw = 34.00 kts
Range 5,500nm at 12.00 kts (Bunkerage = 381 tons)

Complement:
202 - 263

Cost:
£1.385 million / $5.541 million

Distribution of weights at normal displacement:
Armament: 70 tons, 2.3 %
Armour: 340 tons, 11.3 %
- Belts: 143 tons, 4.8 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 19 tons, 0.6 %
- Armour Deck: 178 tons, 5.9 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 1,382 tons, 46.0 %
Hull, fittings & equipment: 873 tons, 29.1 %
Fuel, ammunition & stores: 319 tons, 10.6 %
Miscellaneous weights: 20 tons, 0.7 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,039 lbs / 471 Kg = 15.5 x 5.1 " / 130 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.39
Metacentric height 2.2 ft / 0.7 m
Steadiness - As gun platform (Average = 50 %): 52 %
- Recoil effect (Restricted arc if above 1.00): 0.47
Seaboat quality (Average = 1.00): 1.03

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.510
Length to Beam Ratio: 11.01 : 1
'Natural speed' for length: 23.60 kts
Power going to wave formation at top speed: 65 %
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: 25.00 ft / 7.62 m
- Forecastle (20 %): 16.00 ft / 4.88 m
- Mid (50 %): 16.00 ft / 4.88 m
- Quarterdeck (15 %): 16.00 ft / 4.88 m
- Stern: 16.00 ft / 4.88 m
- Average freeboard: 16.72 ft / 5.10 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 167.2 %
- Above water (accommodation/working, high = better): 143.3 %
Waterplane Area: 12,017 Square feet or 1,116 Square metres
Displacement factor (Displacement / loading): 75 %
Structure weight / hull surface area: 41 lbs/sq ft or 198 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.53
- Longitudinal: 1.31
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent

Quoted

Main Belt covers 154 % of normal length

Problem comes when you get it so that your engines don't fit into the hull anymore. At about 37-38knts this becomes a real problem.

For extra speed, I drop the seakeeping to 0.8 or so. This won't have a great affect for these small ships as they will be pigs in heavy weather anyway.

Quoted

Big and expensive for a leader. What is wrong with Capt. Romani as a model? Or a Tashkent.

The Condottieri I and the Romani Classes were both "destroyer killers" rather than leaders or anything else. They worked quite well until meeting light cruisers (e.g. HMAS Sydney) Just use a 2.000t ship as a leader. The Tribals or the Navigatoris are good examples.

Wes - what single mount? That's the old design. The current (Mk.4) design has 4 x 2 130mm...

RA - I was concerned about that, but leading destroyers is their secondary mission. Their primary mission is as a cruiser minelayer...

Walter - ...which leads me to one concern regarding your SS201 conversion (thanks, BTW ). I remember reading something about how a transom stern isn't a good idea for minelaying? (Also, the steadiness should be 70%.)

Roger - thanks for the offer, but I think I'll stick with my design, it's a tad smaller (ergo, cheaper - my 1929 plan is pushing my material as it is) and has the minelaying capability.

Quoted

Problem comes when you get it so that your engines don't fit into the hull anymore. At about 37-38knts this becomes a real problem.

I know... but wouldn't that mean that your length overall will increase somewhat if those engines stuck out of the end of the hull. :-)

Quoted

...which leads me to one concern regarding your SS201 conversion (thanks, BTW ). I remember reading something about how a transom stern isn't a good idea for minelaying? (Also, the steadiness should be 70%.)

It's just to show that the 34 knots can easily be achieved with this hull. For the real design, I'll stick to your data.

Quoted

I remember reading something about how a transom stern isn't a good idea for minelaying?

HMS Adventure used a transom stern. When she dropped the mines off her stern, they were swept back into the hull and broke the horns off.

34 knots, and no transom.

Filipino Babuyan-class cruiser minelayer, laid down 1929

Displacement:
2,676 t light; 2,786 t standard; 3,004 t normal; 3,180 t full load

Dimensions: Length overall / water x beam x draught
444.37 ft / 435.00 ft x 39.50 ft x 12.00 ft (normal load)
135.44 m / 132.59 m x 12.04 m x 3.66 m

Armament:
8 - 5.12" / 130 mm guns (4x2 guns), 70.00lbs / 31.75kg shells, 1929 Model
Quick firing guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 2.24" / 57.0 mm guns in single mounts, 6.00lbs / 2.72kg shells, 1929 Model
Dual purpose guns in deck mounts
on side ends, evenly spread
3 - 0.98" / 25.0 mm guns (1x3 guns), 0.57lbs / 0.26kg shells, 1929 Model
Anti-aircraft guns in deck mount
on centreline amidships, all raised guns - superfiring
2 - 0.54" / 13.7 mm guns in single mounts, 0.11lbs / 0.05kg shells, 1929 Model
Machine guns in deck mounts
on side, all forward, all raised mounts - superfiring
2 - 0.30" / 7.6 mm guns in single mounts, 0.01lbs / 0.01kg shells, 1929 Model
Machine guns in deck mounts
on side, all amidships

Weight of broadside 586 lbs / 266 kg
Shells per gun, main battery: 150

4 - 24.0" / 610 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1.18" / 30 mm 282.75 ft / 86.18 m 7.54 ft / 2.30 m
Ends: Unarmoured
Main Belt covers 100 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.57" / 40 mm - -
2nd: 0.98" / 25 mm - -
3rd: 0.55" / 14 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 3 shafts, 58,875 shp / 43,920 Kw = 34.00 kts
Range 5,500nm at 12.00 kts (Bunkerage = 394 tons)

Complement:
202 - 263

Cost:
£1.485 million / $5.939 million

Distribution of weights at normal displacement:
Armament: 70 tons, 2.3 %
Armour: 140 tons, 4.6 %
- Belts: 104 tons, 3.5 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 36 tons, 1.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 1,562 tons, 52.0 %
Hull, fittings & equipment: 884 tons, 29.4 %
Fuel, ammunition & stores: 329 tons, 10.9 %
Miscellaneous weights: 20 tons, 0.7 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
730 lbs / 331 Kg = 10.9 x 5.1 " / 130 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.16
Metacentric height 1.6 ft / 0.5 m
Roll period: 12.9 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.69
Seaboat quality (Average = 1.00): 0.90

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.510
Length to Beam Ratio: 11.01 : 1
'Natural speed' for length: 20.86 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 78
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 1.00 ft / 0.30 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23.00 ft / 7.01 m
- Forecastle (18 %): 17.00 ft / 5.18 m
- Mid (50 %): 14.50 ft / 4.42 m
- Quarterdeck (15 %): 14.50 ft / 4.42 m
- Stern: 14.50 ft / 4.42 m
- Average freeboard: 15.76 ft / 4.80 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 186.4 %
- Above water (accommodation/working, high = better): 130.0 %
Waterplane Area: 11,553 Square feet or 1,073 Square metres
Displacement factor (Displacement / loading): 69 %
Structure weight / hull surface area: 43 lbs/sq ft or 212 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.55
- Longitudinal: 1.09
- Overall: 0.59
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
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather