WesWorld

To be laid down Q1 1925.

Following extensive trials with the Hybrid carrier the RHN has identified it's carrier requirements. The CT allows 30k tons of carriers. This is to be divided into two ships. The requirement for two ships is so that there
is the expectation that at least one will be available at all times.

The carrier must have good torpedo defence in what is potentially a high risk area in the eastern med with large numbers of hostile torpedo craft.

15k tons was insufficient to allow an adequate anti surface armament. The best that could be hoped for was a dual anti-MTB and anti-air fast firing light guns. As such these ships would not be able to operate
independently as the big US carriers could.

The original proposal included two flyoff decks however the lower one was given up in the interest of increased hangar length and a raised forecastle to improve seaworthiness.

The landing deck is canted aft so there is an uphill run for aircraft landing that will aid in arresting aircraft. Palisades are fitted to catch wayward aircraft from running over the side.

The design has a single hangar deck. A second one was proposed for the two flight deck design however stability in the event of a torp hit was an
issue. The single hangar has significantly reduced aircraft storage but as a compromise it is hoped that there is sufficient height in the single hangar to allow slinging spare aircraft from the ceiling. The maximum
is 42 aircraft however the operational maximum and hangar floor capacity is about 30 aircraft.



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CV1925, GREEK Carrier laid down 1925

Displacement:
14,663 t light; 15,002 t standard; 16,550 t normal; 17,722 t full load
Loading submergence 816 tons/feet

Dimensions:
664.00 ft x 76.80 ft x 27.00 ft (normal load)
202.39 m x 23.41 m x 8.23 m

Armament:
24 - 2.00" / 51 mm guns8 - 0.50" / 13 mm AA guns
Weight of broadside 97 lbs / 44 kg

Armour:
Belt 4.50" / 114 mm, ends unarmoured
Belts cover 120 % of normal area
Armour deck 2.50" / 64 mm, Torpedo bulkhead 1.00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 83,875 shp / 62,571 Kw = 30.00 kts
Range 8,500nm at 15.00 kts

Complement:
729 - 948

Cost:
£2.961 million / $11.842 million

Distribution of weights at normal displacement:
Armament: 12 tons, 0.1 %
Armour: 2,771 tons, 16.7 %
Belts: 1,020 tons, 6.2 %, Armament: 0 tons, 0.0 %, Armour Deck: 1,320 tons, 8.0 %
Conning Tower: 0 tons, 0.0 %, Torpedo bulkhead: 431 tons, 2.6 %
Machinery: 2,723 tons, 16.5 %
Hull, fittings & equipment: 4,757 tons, 28.7 %
Fuel, ammunition & stores: 1,887 tons, 11.4 %
Miscellaneous weights: 4,400 tons, 26.6 %

Metacentric height 3.7

Remarks:
Hull space for machinery, storage & compartmentation is cramped
Room for accommodation & workspaces is excellent
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: 1.05
Shellfire needed to sink: 12,527 lbs / 5,682 Kg = 116.0 x 6 " / 152 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 2.0
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 71 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.01
Relative quality as seaboat: 1.31

Hull form characteristics:
Block coefficient: 0.421
Sharpness coefficient: 0.32
Hull speed coefficient 'M': 7.97
'Natural speed' for length: 25.77 kts
Power going to wave formation at top speed: 49 %
Trim: 54
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 112.9 %
Relative accommodation and working space: 134.3 %
(Average = 100%)
Displacement factor: 130 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0.99
(Structure weight / hull surface area: 102 lbs / square foot or 498 Kg / square metre)
Relative longitudinal hull strength: 1.12
(for 18.00 ft / 5.49 m average freeboard, freeboard adjustment 1.25 ft)
Relative composite hull strength: 1.00

Cheers,

Love the drawing. A unique looking carrier, to be sure.

Interesting design, but I'm not sure the torpedo bulkhead is worth the space on a ship of this size.

The ship's belt and deck are sufficient to protect it from longer range destroyer and cruiser fire - however, she lacks both the speed to escape cruisers and the armament to fight them off. This may be a problem in your neighbourhood.

What airgroup would you envision carrying? Is it a strike group, balanced, or air-defence heavy?

SR Urumi is also getting a Q1/25 lay-down, and takes a somewhat different approach to this size of carrier: no bulkhead, greater speed, and substantially heavier armament.

On a ship of this size, you'd probably get better torpedo restisance by removing the bulkhead (odd as that sounds)...

Second Rocky's opinion on the drawing.

Unless Greece has a lot of of destroyers and cruisers to protect her, she is toast.

Get to about 150hm and open up with 6", 130mm or 100mm guns. There's no armour protecting the aeroplanes (and no hull in places) so it should be easy to get a nice fire started in the hangar. And all those closely packed canvas and wood aeroplanes will burn real well.

It doesn't really matter that her vitals are protected. You don't have to hit her there to cripple her.


SR Urumi is a bit harder to crack, but she can fall in the same way. Its just harder to catch her, and less safe for the pursuing cruisers.

BTW, superstructure is on the starboard side of carriers;

In WWI, the RN was deciding where to put the superstructure. Someone asked the pilots which way they would turn on an aborted landing, and all said they'd turn to port. Hence, the island goes on the starboard side.

If you're referring to Urumi's original port-side island, I've since revised it - just haven't posted any revisions. I've been tinkering with the design and haven't quite settled on the final design.

You're quite right that a carrier like Urumi is in a bad way if a cruiser comes knocking, but the point is to make it less one-sided.

I agree with some of the others here, she should ditch that torpedo bulkhead, that wil add some room to increase her speed.

A carrier should always be able to run from whatever she cannot slug it out with.

Thanks for the feedback,

I'd thought that 15k tons was the lower limit for a TDS to be of benefit. I'll have a tinker. I still have time to modify the design.

Harry's hybrid carrier had funnels offset to both sides so we would learn what works and what doesn't, and the pilots saying 'don't @#$%^ put it there!'.

Quoted

Unless Greece has a lot of of destroyers and cruisers to protect her, she is toast.

Are them's fight'n' words Red Admiral? ; )

You are quite right, without powerful escort, they are toast but what carrier isn't. Personally I'd like another 20k tons of carriers for 2 25,000ton ships and give these two ships the extra speed, airgroup, armour and gunpower they need but I don't. The CT doesn't even let me build 1 30k ton carrier - too big.

Airgroup is 1 squadron of fighters (12ac), 1 squadron of torpedo aircraft (12ac) and one scout squadron (12ac). The drawing has 30 ac but they are all torpedo bomber size (90% of a Swordfish's dimentions) so the extra 6 ac would squeeze in as the fighters are smaller.

Cheers

Hi alt naval,

I like her. I think 30 knots is plenty for a carrier for this (sim) era. Doctrine and application are more important than individual statistics. Their most important contibutions will be in providing experience, for officer and enlisted alike. I realize this is a sim, but everything from deck handling to strategy and tactics has to be learned, and will be on these ships. From a realism standpoint, it's not 'just going to happen.'

I think your point about torpedoes and stability is well taken. If Greece were going for a fully offensive, power projection fleet, I'd say these ships might be inadequate. But given what you've shown so far, they fit in well. Something I've come to expect from you, but that's beside the point.

My only concern is the ramp forward. How does changing the aircraft's angle of attack affect lift? I.e ., in a conventional tail-down, three point aircraft, the angle of attack for take of is naturally suited to lift at low speed, especially in a biplane. More wing surface area exposed to wind with forward movement; for a modern example, think of the F8U/F-8 Crusader's canted two position wing. It was raised (the front angled up from horizontal) for a better angle of attack during take off and landing. A lot of text for a minor concern.

Regards,

Big Rich

Quoted

Originally posted by 1Big Rich
My only concern is the ramp forward. How does changing the aircraft's angle of attack affect lift? I.e ., in a conventional tail-down, three point aircraft, the angle of attack for take of is naturally suited to lift at low speed, especially in a biplane. More wing surface area exposed to wind with forward movement; for a modern example, think of the F8U/F-8 Crusader's canted two position wing. It was raised (the front angled up from horizontal) for a better angle of attack during take off and landing. A lot of text for a minor concern.

Regards,

Big Rich

The problem with suddenly increasing the angle of incidence is there is a corresponding increase in the amount of DRAG on the airframe, with a resultant DROP in airspeed. No tail-dragger can take off with all it's wheels on the ground (at least not in the 20's!)

Now, where as the F8 Crusader is a valid comparison for purposes of increaseing the angle of attack, the reason it was done on it was because the fuselage is long in relation to the short but strong undercarraige required for carrier operation to allow the fuselage to rotate normally - so if you can't drop the tail, you have to raise the wing!!

You also have to bear in mind that the F8 had a thrust to weight ratio greater than 1:1, and it was in the 60's before that situation became common with other aircraft, so a drag-ridden biplane of the early 20's would have NO excess of power to haul it into the air past the stall that would be induced by the incidence change.

One last thing, if the Greek carrier in her current configuration was steaming hard into a headwind to help it's planes into the air, there would be an amount of lift generated at the break in the flight deck (as wind will flow like water along a flat surface, so forming a "ripple" or "rapid" at the break), which could cause the planes to break contact with the deck BEFORE they had sufficient airspeed, causing them to stall and crash on the bow, or end of the ramp, forcing a halt in flight ops.

I hope I've explained this in a way you can understand, I've been flying R/C models for about 16 years, and it's sometimes difficult to put into words what experience has thought me!

Wow! Care to make similar predictions with some of the other sim carriers? You seem to know your stuff in this reguard.

Must admit I haven't given much thought to it, as I firmly believe that aircfarf of the time aren't up to it!!
RA just confirmed my ideas. Denmark currently has no plans for a carrier before 1928, but the lads are practicing on a painted A/C deck at NAS Holbaek.
I have a bucket load of experience of model aircraft flying characteristics which are very similiar to early aircraft, very light, quite flimsy, and usually underpoweded ( most modelers HUGELY overpower their models as a little insurance (a model going vertically up is in little danger of crashing!)

I'll go back over the other designs and look at them for an aerodynamic point of view, and let you know!

It would be nice to give our carriers little quirks to give them their own personality's.

Quoted

Originally posted by thesmilingassassin
It would be nice to give our carriers little quirks to give them their own personality's.

True, but not one's that could kill your pilots!!

I was using the short flight deck on the RN 1920's carriers as a model. The Japanese did similar things with regards to a sloped deck. A preliminary design for Soryu had a similar 'humped' apearance. Apparently a biplane can takeoff with little wind over deck. It wasn't a problem so much untill heavier aircraft were used and then the need for a catapult.

Perhaps the down ramp should be 'eased' slightly.

Cheers,