WesWorld

We recetnly discussed escort cruisers, I decided to pay around with a light design:

Protecdor, Iberia CLE laid down 1925

Displacement:
4,672 t light; 4,863 t standard; 5,639 t normal; 6,238 t full load
Loading submergence 422 tons/feet

Dimensions:
459.32 ft x 50.85 ft x 16.73 ft (normal load)
140.00 m x 15.50 m x 5.10 m

Armament:
8 - 6.00" / 152 mm guns (2 Main turrets x 4 guns)
12 - 2.24" / 57 mm AA guns
8 - 0.53" / 14 mm guns
Weight of broadside 932 lbs / 423 kg
8 - 23.6" / 600 mm above water torpedoes

Armour:
Belt 3.94" / 100 mm, ends unarmoured
Belts cover 94 % of normal area
Main turrets 3.94" / 100 mm, AA gun shields 1.18" / 30 mm, Light gun shields 0.59" / 15 mm
Armour deck 1.57" / 40 mm, Conning tower 3.15" / 80 mm

Machinery:
Oil fired boilers, steam turbines plus diesel motors,
Electric cruising motors plus geared drives, 2 shafts, 39,024 shp / 29,112 Kw = 28.00 kts
Range 8,000nm at 15.00 kts

Complement:
325 - 422

Cost:
£1.436 million / $5.744 million

Distribution of weights at normal displacement:
Armament: 117 tons, 2.1 %
Armour: 1,044 tons, 18.5 %
Belts: 392 tons, 6.9 %, Armament: 201 tons, 3.6 %, Armour Deck: 431 tons, 7.6 %
Conning Tower: 21 tons, 0.4 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 1,267 tons, 22.5 %
Hull, fittings & equipment: 2,124 tons, 37.7 %
Fuel, ammunition & stores: 967 tons, 17.1 %
Miscellaneous weights: 120 tons, 2.1 %

Metacentric height 2.2

Remarks:
Hull space for machinery, storage & compartmentation is adequate
Room for accommodation & workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.11
Shellfire needed to sink: 7,227 lbs / 3,278 Kg = 66.9 x 6.0 " / 152 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 1.3
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 70 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.43
Relative quality as seaboat: 1.09

Hull form characteristics:
Block coefficient: 0.505
Sharpness coefficient: 0.34
Hull speed coefficient 'M': 7.89
'Natural speed' for length: 21.43 kts
Power going to wave formation at top speed: 57 %
Trim: 64
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 91.6 %
Relative accommodation and working space: 99.7 %
(Average = 100%)
Displacement factor: 122 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0.95
(Structure weight / hull surface area: 87 lbs / square foot or 425 Kg / square metre)
Relative longitudinal hull strength: 1.51
(for 16.40 ft / 5.00 m average freeboard, freeboard adjustment 2.90 ft)
Relative composite hull strength: 1.00

Are you really going to build this? It is a 28knt light cruiser; i.e. it is useless. The escort cruiser i was talking about earlier, rated as CDA tonnage because it wasn't faster than 24knts or larger than 8,000t.

The armour shoul;d maybe be a bit thicker as well.

I don´t like medium sized quad mounts....

While armor and broadside are not bad for the displacement it is still not a very useful design. It will be ~4kn slower than the average light or heavy cruiser and even have problems to outrun most modern capital units. Thus it can´t outrun what it can´t outgun (DDs for example) and will be easily sunk. Any normal 15cm gun (L/50, muzzle energy 1.00 using BigGun) can punch through 100mm of facehardend armor inside 13.000m - the faceplates maybe even further away given their angle and thus the angle of impact. And if homogenous armor is used (not unlikely for a 100mm plate) resistance against shell fire is even lower.

To sum it up: You need either more speed or more protection. Otherwise you´re only fresh meat for the hungry dogs out there.

Have fun,

HoOmAn

PS: A 12,7cm L/50 DD gun using a 30kg AP shell can pierce through 100mm facehardend armore well inside 8500m. Think about it.

folks show me any light cruiser in the early 1920s that had 100 mm armour or any cruiser before the brooklyns that was armoured against it's own guns. what are we doing here?

and this ship is specifically built for convoy escort where there is no need of chasing down an enemy - he is coming to you anyway. and colonial duty usually means wog-bashing. again plenty performance for the purpose.

Bernhard

I don´t question your design (or your spring*-skills). You got a decent design for its size. I question the doctrine behind it.

It can´t outrun what it can´t outgun (and it can´t outgun what it can´t outrun - at least to some degree).

Further more such a special purpose cruiser can´t be used for anything else.... I rate it as a waste of time, effort, material and money.

But that´s just me of course...

HoOmAn

PS: And history has proven one thing: You don´t need armor to survive or win a gun fight. Redundant systems, damage controll and good luck can do the trick as well. Most shells will hit unarmored areas anyway given the narrowness of most designs belts....

good point. mind you I am posting the result ofour chat discussion anyway, I dunno, If i am ever going to buid her ... And i know you don't like her hooman :-)

Protecdor, Iberia CLE laid down 1925

Displacement:
4,655 t light; 4,868 t standard; 5,763 t normal; 6,456 t full load
Loading submergence 439 tons/feet

Dimensions:
459.32 ft x 52.49 ft x 16.40 ft (normal load)
140.00 m x 16.00 m x 5.00 m

Armament:
8 - 3.94" / 100 mm guns (2 Main turrets x 4 guns, 2 superfiring turrets)
8 - 6.00" / 152 mm guns (2 2nd turrets x 4 guns)
12 - 2.24" / 57 mm AA guns
8 - 0.53" / 14 mm guns
Weight of broadside 1,177 lbs / 534 kg
8 - 23.6" / 600 mm above water torpedoes

Armour:
Belt 5.91" / 150 mm, ends unarmoured
Belts cover 63 % of normal area
Main turrets 7.09" / 180 mm, 2nd turrets 3.15" / 80 mm
AA gun shields 1.18" / 30 mm, Light gun shields 0.59" / 15 mm
Armour deck 1.97" / 50 mm, Conning tower 5.91" / 150 mm

Machinery:
Oil fired boilers, steam turbines plus diesel motors,
Electric cruising motors plus geared drives, 2 shafts, 21,565 shp / 16,088 Kw = 24.00 kts
Range 9,000nm at 15.00 kts

Complement:
330 - 429

Cost:
£1.258 million / $5.033 million

Distribution of weights at normal displacement:
Armament: 147 tons, 2.6 %
Armour: 1,401 tons, 24.3 %
Belts: 401 tons, 7.0 %, Armament: 400 tons, 6.9 %, Armour Deck: 559 tons, 9.7 %
Conning Tower: 41 tons, 0.7 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 700 tons, 12.1 %
Hull, fittings & equipment: 2,287 tons, 39.7 %
Fuel, ammunition & stores: 1,108 tons, 19.2 %
Miscellaneous weights: 120 tons, 2.1 %

Metacentric height 2.2

Remarks:
Hull space for machinery, storage & compartmentation is excellent
Room for accommodation & workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.07
Shellfire needed to sink: 10,039 lbs / 4,554 Kg = 329.0 x 3.9 " / 100 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 2.1
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 70 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.45
Relative quality as seaboat: 1.28

Hull form characteristics:
Block coefficient: 0.510
Sharpness coefficient: 0.35
Hull speed coefficient 'M': 7.83
'Natural speed' for length: 21.43 kts
Power going to wave formation at top speed: 49 %
Trim: 55
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 62.3 %
Relative accommodation and working space: 90.9 %
(Average = 100%)
Displacement factor: 141 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0.97
(Structure weight / hull surface area: 95 lbs / square foot or 466 Kg / square metre)
Relative longitudinal hull strength: 1.31
(for 14.44 ft / 4.40 m average freeboard, freeboard adjustment 0.87 ft)
Relative composite hull strength: 1.00

I don´t like her....


*ggg*

well, took a look at my cruiser tonnage and other plans last night - she ain't gonna happen ...

Bernhard

I wouldn't use cruiser-tonnage for that purpose either. In Iberia's situation, coast-defence ships aren't necessarily that useful, but you can get 10 4000ton vessels out of the available tonnage, and for convoy-escorting you should not need more than 24 knots anyway.