WesWorld

Is she worth it? Meant to act as fleet scout and escort for minor fleet operations.

CVL36A, South African Light Fleet Carrier laid down 1936

Displacement:
9.645 t light; 9.928 t standard; 10.835 t normal; 11.560 t full load

Dimensions: Length overall / water x beam x draught
589,67 ft / 574,15 ft x 65,62 ft x 19,36 ft (normal load)
179,73 m / 175,00 m x 20,00 m x 5,90 m

Armament:
8 - 4,53" / 115 mm guns (4x2 guns), 46,40lbs / 21,05kg shells, 1936 Model
Breech loading guns in deck mounts with hoists
on centreline ends, evenly spread, all raised mounts - superfiring
8 - 1,57" / 40,0 mm guns (4x2 guns), 1,95lbs / 0,89kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
8 - 0,79" / 20,0 mm guns (4x2 guns), 0,24lbs / 0,11kg shells, 1936 Model
Machine guns in deck mounts
on side, evenly spread, 3 raised mounts
Weight of broadside 389 lbs / 176 kg
Shells per gun, main battery: 300

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1,38" / 35 mm 0,98" / 25 mm 1,38" / 35 mm
3rd: 0,59" / 15 mm - -
4th: 0,39" / 10 mm - -

- Armour deck: 1,97" / 50 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 93.833 shp / 70.000 Kw = 32,09 kts
Range 7.000nm at 15,00 kts
Bunker at max displacement = 1.631 tons

Complement:
530 - 690

Cost:
£3,939 million / $15,755 million

Distribution of weights at normal displacement:
Armament: 49 tons, 0,4%
Armour: 962 tons, 8,9%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 31 tons, 0,3%
- Armour Deck: 931 tons, 8,6%
- Conning Tower: 0 tons, 0,0%
Machinery: 2.633 tons, 24,3%
Hull, fittings & equipment: 3.601 tons, 33,2%
Fuel, ammunition & stores: 1.190 tons, 11,0%
Miscellaneous weights: 2.400 tons, 22,2%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
11.605 lbs / 5.264 Kg = 250,1 x 4,5 " / 115 mm shells or 1,5 torpedoes
Stability (Unstable if below 1.00): 1,14
Metacentric height 3,4 ft / 1,0 m
Roll period: 15,0 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0,09
Seaboat quality (Average = 1.00): 1,02

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,520
Length to Beam Ratio: 8,75 : 1
'Natural speed' for length: 23,96 kts
Power going to wave formation at top speed: 59 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 25,00 degrees
Stern overhang: 3,28 ft / 1,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 26,25 ft / 8,00 m
- Forecastle (20%): 19,36 ft / 5,90 m
- Mid (45%): 19,36 ft / 5,90 m
- Quarterdeck (25%): 19,36 ft / 5,90 m
- Stern: 19,36 ft / 5,90 m
- Average freeboard: 19,91 ft / 6,07 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 107,0%
- Above water (accommodation/working, high = better): 177,9%
Waterplane Area: 25.567 Square feet or 2.375 Square metres
Displacement factor (Displacement / loading): 120%
Structure weight / hull surface area: 93 lbs/sq ft or 453 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,97
- Longitudinal: 1,29
- Overall: 1,00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

Quoted

Ship tends to be wet forward

Not good on a carrier.

How many aircraft is she supposed to operate?


No belt armor is a bit dangerous, I'd think, but on a CVL it's MAYBE OK.

Maybe you guys know this one already but in case you dont... at ~2:00 => "Ship tends to be wet forward"
http://www.youtube.com/watch?v=F3OAPYJprIk

Aim for 40 aircraft - on what is a fairly tiny carrier - and you'd be able to raise the freeboard a fair bit. Would make for a better seakeeping value and perhaps a dry deck.

40 aircraft would be rather problematic off such a small ship. It'd probably be more like 15-18 aircraft, and light ones as well. Its probably not worth it compared to the big one.

Have to disagree, RA: the historical USN Casablanca class, which was 25m shorter (with similar dimensions in beam and draught) were rated for 27 aircraft.

Ok then, effectively operate 15-18 aircraft.

Don't agree again: the USS Fanshaw Bay, a member of the class, was operating up to 30 aircraft off Okinawa, and was operating 28 before her participation in the Battle off Samar. See here: http://www.navybuddies.com/cve/cve70.htm

I actually hoped she would be capable to operate about 36 planes (three squadrons) because she´s purpose build compared to those OTL conversions. IIRC, the american CVLs of WW2 could operate up to 48 aircraft of ~11000ts....?!

The formula to calculate maximum plane capacity allows even more planes, though.

I think the ship tends to be wet comment refers to the hull. Actually I have no problem with her bow being washed over as long as flight deck is not - and the latter will be several meters above her hull.

Btw, this carrier below is capable carrying 26 planes in her two storray hangar. I checked it using my templates (I just can´t upload pics currently). Of course she´s totally crowded but there is room for 12 in her lower and 14 in her upper hangar deck. The lower deck extends from the end of her belt to the aft end of her superstructure while the upper hangar takes all the room inside her superstructure aft of her main guns.

I expect her to carry only ~18 during standard operations, however.

The RN is studying smaller light carriers. For patrols and anti-raider hunting this carrier should be ok. I'd make her a bit larger, having room for growth is a good thing.

I'd add a belt too, even if its only over the machinery spaces.

A scout carrier might not need over 40 planes so 26 should be enough for ample scout bombers and few fighters.

Overall interesting. It's smaller than the 170m carrier the Dutch proposed during the Argentine competition, but has the same airgroup.

Edit : Which reminds me.. 70, 120, 170.. don't you want to strike 5m off of her?

I would say the proper analogy is the US Independence class, which was a similar size. If the RSAN flight deck is full-length, then it may match Independence.

However, if the vessel is "wet forward" then don't you have a chance of water in / damaging your hanger- which is only superstructure elements?

I'm not all that 'up' on US Escort carriers, but I thought they had fairly substantial limitations- Further, I thought US aircraft numbers were bolstered by deck parks.

-poor support services
-lack of spares
-reliance on a catapult for heavy AC
-Landing ops may not be doable while launching, due to available deck space (as noted the Casablancas were even shorter).

The last two of those supposedly have to do with rising aircraft weight and performance, and greater wingloadings, so are likely not apparent quite yet.

The escort carriers were also slow. The light carriers, built on "light cruiser" hulls, were faster than their tanker and freighter coverted escort type cousins.

Thanks for your comments. I´ll probably revise her due to some comments, make her a bit larger to make sure she can operate the number of aircraft I plan.

Regarding length - 170m seems too short to me. The design above has a total hull length of nearly 180m and her flight deck might even add another meter or two what I would welcome to have more space for deck operations. So I´m not focusing on dock length...

Wet forward - I never really understood how SS calculates that and what it really means. Wet under what conditions? She is not that large a ship, for sure, and like many cruisers and other vessels she tends to take water over her bow in heavy seas. There´s nothing surprising in this fact. Adding a few tons and some freeboard might help but if a complete re-design is necessary to get rid of that note I prefer to keep her as is instead. She features all the RSAN needs and her seakeeping is not exceptionally bad, so spenging much more money and material might not be worth it.

Re-designed:

- slightly larger due to more length
- better seaboat
- slightly increased misc. weight

Assuming two storray hangar - capable to operate 48 aircraft?

CVL36B, South African Light Fleet Carrier laid down 1936

Displacement:
9.885 t light; 10.162 t standard; 11.082 t normal; 11.818 t full load

Dimensions: Length overall / water x beam x draught
603,56 ft / 587,27 ft x 65,62 ft x 19,36 ft (normal load)
183,96 m / 179,00 m x 20,00 m x 5,90 m

Armament:
8 - 4,53" / 115 mm guns (4x2 guns), 46,40lbs / 21,05kg shells, 1936 Model
Breech loading guns in deck mounts with hoists
on centreline ends, evenly spread, all raised mounts - superfiring
8 - 1,57" / 40,0 mm guns (4x2 guns), 1,95lbs / 0,88kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
8 - 0,79" / 20,0 mm guns (4x2 guns), 0,24lbs / 0,11kg shells, 1936 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 389 lbs / 176 kg
Shells per gun, main battery: 250

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1,38" / 35 mm 0,98" / 25 mm 1,38" / 35 mm
3rd: 0,59" / 15 mm - -
4th: 0,39" / 10 mm - -

- Armour deck: 1,97" / 50 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 93.833 shp / 70.000 Kw = 32,08 kts
Range 7.000nm at 15,00 kts
Bunker at max displacement = 1.656 tons

Complement:
539 - 702

Cost:
£3,983 million / $15,932 million

Distribution of weights at normal displacement:
Armament: 49 tons, 0,4%
Armour: 983 tons, 8,9%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 31 tons, 0,3%
- Armour Deck: 952 tons, 8,6%
- Conning Tower: 0 tons, 0,0%
Machinery: 2.633 tons, 23,8%
Hull, fittings & equipment: 3.720 tons, 33,6%
Fuel, ammunition & stores: 1.197 tons, 10,8%
Miscellaneous weights: 2.500 tons, 22,6%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
12.265 lbs / 5.563 Kg = 264,3 x 4,5 " / 115 mm shells or 1,6 torpedoes
Stability (Unstable if below 1.00): 1,14
Metacentric height 3,4 ft / 1,0 m
Roll period: 14,9 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0,08
Seaboat quality (Average = 1.00): 1,07

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,520
Length to Beam Ratio: 8,95 : 1
'Natural speed' for length: 24,23 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 48
Bow angle (Positive = bow angles forward): 25,00 degrees
Stern overhang: 3,28 ft / 1,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 27,89 ft / 8,50 m
- Forecastle (30%): 19,36 ft / 5,90 m
- Mid (45%): 19,36 ft / 5,90 m
- Quarterdeck (25%): 19,36 ft / 5,90 m
- Stern: 19,36 ft / 5,90 m
- Average freeboard: 20,38 ft / 6,21 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 105,5%
- Above water (accommodation/working, high = better): 178,9%
Waterplane Area: 26.151 Square feet or 2.430 Square metres
Displacement factor (Displacement / loading): 121%
Structure weight / hull surface area: 93 lbs/sq ft or 455 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,97
- Longitudinal: 1,28
- Overall: 1,00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

Critereon for being wet forward is freeboard at stem greater than 1.1 * root w.l. which is from DK Brown and the experience in the first world war. Wet forward means lots of spray everywhere, especially on the bridge. It doesn't mean she is going to be swamped. What works best for seakeeping is size. A 40000ton battleship will be a good seaboat compared to just about anything else afloat.

In case of my CVL it worked to just increase stem by half a meter. Thanks for explaining the formula.