WesWorld

Quoted

10 Vessels laid down late 1932

Adua, Alagi, Aradam, Ascianghi, Axum, Beilul, Dagabur, Dessié, Durbo, Gondar

A smaller type more useful for operations in the Eastern Med. and Red Sea

Because of the need for operations in confined waterspaces close to land this class is considerably different. The hull is not strengthened to the same extent as previous, crush depth being 125m instead of the previous 180m. The hull is more streamlined with no deck gun being carried. For operations close to land it was thought better to remain submerged. The 1600hp electric motors and batteries have been taken from the previous Antonio Sciesca Class. This large increase in power and the more streamlined hull gives a faster underwater speed of 16knts. Nearly enough to avoid escorting vessels. A 750hp Fiat Diesel is used for surface propulsion and to charge the batteries. For the first time the Mililiter device will be fitted to a class as a whole after succesful trials from 1925 onwards onboard S3. This will help again in having the submarines remain underwater and undetected. 4x533mm torpedo tubes are fitted forwards with 8 torpedoes carried. A D3 sonar set is carried forwards to help with ranging and early warning.

Hi RA,

nice background story for your new submarines. Knowing you I guess there is historical precedence for this modern if not revolutionary design concept?

Thanks,

HoOmAn

Historical precedent for which bit exactly?

High speed submarines:- R-class in WWI at 15knts
Submarine mounted sonar:- hydrophones on R-class, type 118/120 with dome used in RN River class
Mililiter[Italian Schnorkel]: designed in 1919, succesful trials on H3 in 1924/25. Planned to fit to Sirena class in 1931 but never was and production for this class was destroyed. No reasons given.
Streamlining:- not particularly difficult

I wouldn't say that its a revolutionary concept, just that a submarine will die rather quickly if it stays surfaced in the Eastern Med. Higher underwater speed is useful for getting into position and escape against older Greek/Turkish/Atlantean units. For this specialised role they make sense. For longer operations further away from land there is no need, so its better to emphasise "boat" qualities.

Btw, you realy like soviet navy vessel, don´t you? ;o)

Or is it coincidence that your latest CL design resembles the soviet KARA-class guided missle cruisers?!

Quoted

Originally posted by Red Admiral
Historical precedent for which bit exactly?

High speed submarines:- R-class in WWI at 15knts

Sorry for not being precise.

Yes, the Rs achieved around 14kn submerged and were somehow comparable to your design. Any reports how they were handled during operations? Were they rated successfull?

(Btw, the USN R-class of 1918 achieved 12kn surfaced and 9kn submerged according to my sources. Just to make sure nobody´s confused.)

Streamlining is in fact more difficult than one may think as you need to understand the theory behind and you need some facilities (watertank equivalents to wind tunnels) to push such a design from idea into reality. Do you have OTL-sources about these kind of works? I wonder why the Germans in 1943 were the once to introduce the concept (again) but nobody else made good use of it?!

Leaving the deck gun at home also is kind of special in the early 30s when compared with OTL. The Rs of course, but others?

The one thing that I find odd is that, historically, at this period the threat to subs was seen as being ASDIC, not detection on the surface. Radar, after all, is still mostly in the labs of various powers, while hydrophones were used during the Great War and it's a small jump from there to active sonar. Which helps explain why, historically, the Dutch were the first to field submarines with schnorkels, and why both the Royal Navy and the Kriegsmarine had them removed from the Dutch boats they received after the conquest of the Netherlands.

As far as the deck gun goes, the German Type II U-boats carried only a single 2cm gun, pretty close to leaving the deck gun at home.

Definitely coincidence about Saint C and Kara. Shes modelled more after HMS Bristol here. I needed lots of space for magazines and the fighter direction station. No heavy AA makes things easier to fit. Not great offensive warships but they're more useful for their command/control role in trying to link surface and air forces together.

The R-class were reasonably succesful. They operated mostly in the North Sea and Baltic. Their contemporary L and H classes were reasonably fast underwater as well. They didn't sink like other RN classes. Some of the H class gave good service in Italy until they were retired in 1947.

Streamlining needs a different hullform for submerged or surfaced. The emphasis was more on surface speed so the submerged speed got left behind a lot. Basically they were mobile minefields rather than _proper_ submarines. I'm sure that Naples and Fiume have testtanks for their torpedoes. They did a lot of work on shape interwar in which they were succesful. Different head shapes gave 2knts extra speed. I'd take my picture as an "artists impression" rather than what they actually look like. I'm bad at drawing subs.

Deck gun. You surface to shell a freighter and artillery from a nearby island starts firing at you. More trouble than its worth for this role.

Quoted

The one thing that I find odd is that, historically, at this period the threat to subs was seen as being ASDIC, not detection on the surface.

Fair enough but I think Italy is safe in assuming that the Greeks/Turks/Indians have eyes and would see a surfaced submarine close to land.

Quoted

Fair enough but I think Italy is safe in assuming that the Greeks/Turks/Indians have eyes and would see a surfaced submarine close to land.

Didn't prove to be too much of a problem for the U-boats that operated in the Med during the Great War. A surfaced sub is very small, in comparison to most vessels, because the only easily visible part of it's the sail, the main hull is low in the water and easily hidden by waves.

I think she´s actually closer to KARA than to BRISTOL... I always thought those russion missle cruisers/destroyers look so damn cool compaired to their US equivalents. Probably a real source for some WesWorld drawings. Got to check some of my sources. hehe

I have to agree; Russian "sledgehammer tough (and looking like one too)" ships do have that visual appeal...

(As opposed, to say, Ugly Funnel Syndrome or ghastly pagodas. :-P )

Having mulled it over, I guess I'd have to agree with Stephen that this is a fairly revolutionary design. Schnorkels weren't in use until five years into WW2; serious efforts at streamlining didn't happen until about the same time. I'm not so certain about the inclusion of active sonar - nonetheless, that's a lot of cutting-edge ideas being packaged together over a decade earlier than historical.

Could I get a bit of an explanation about the cruiser, please?

Serious, and successful, attempts at underwater streamlining for submarines didn't really happen until the German experimental submarine V-80 in the late 30s-early 40s, and mostly there because Walter was trying to show the KM the advantages of the hydrogen peroxide propulsion system by breaking underwater speed records by a large margin. Yes, the Italians did gain some speed on their torpedoes by streamlining them, but those torpedoes were near-contemporaries with V-80.

Actually the H.L. Hunley featured a snorkel... not that that one really worked...
"The Hunley had a primitive snorkel to raise submerged, but its 1 1/2-inch diameter was too small for air supply." (from here)
Took 80 years and the Dutch to 'reinvent' the snorkel for use aboard a submarine.

Proud to be Dutch. :-)

Quoted

because Walter was trying to show the KM the advantages of the hydrogen peroxide propulsion system by breaking underwater speed records by a large margin.

Yes, I know what's good for the Kriegsmarine. ;-)

Heh. Non-working items are not counted as advances....

The Turtle had a snorkel and it worked...

The Turtle was a one man machine. Thus it only needed to get air for the human and not the engine or multiple humans.

I'd wonder about the lack of a deck gun at this time. If I recall tactics, the idea of catching a civilian ship alone was to use the deck gun to save on the rather limited number of torpedoes. Also I believe international law at this time still suggested that one warn a civilian vessel that it will be sunk and to take the crew captive (something a submarine can't do very well). If I recall this was one of the primary objections the Americans had against the Germans over the British Blockade of Germany. It was ungentlemenly to sink a ship without warning and without giving non-combatants time to leave their vessel. While the British still intercepted shipping heading to Germany and other Central Powers, thus causing anger from the nuetrals such as the Americans, the submarine warfare was considered worse. Especially the unrestricted warfare used at various times during the war.

But then the ship's design in usually reflective of its intended mission, or a goal of the designing company/country.

Quoted

that's a lot of cutting-edge ideas being packaged together over a decade earlier than historical.

A single class of vessels designed for a specific task: sinking large parts of either the Greek or Turkish Navy very quickly. Neither Navy is likely to have active sonar, just hydrophones. They'll know something is up when they get pinged, but when torpedoes arrive 2-3minutes later it is too late. Its also worth noting that sonar and hydrophones don't work particularly well in shallow waters. This makes it easier for the submarine to run away and get lost in all the echoes. Streamlining works to improve underwater range as well as speed through a reduction in drag. When incorporated with mililiter and spending lots of time underwater it makes good sense.

If Italy wanted to build an advanced submarine, they build this;

So I'm to believe that the next class of Italian submarines isn't going to carry active sonar, isn't going to carry mililiter, and isn't going to be unusually fast underwater?

I have to agree with Rocky and Hoo, so many advances in one ship type and in some numbers seems unrealistic.

....and here I thought putting an experimental streamlined coning tower and larger torpedo's on my extra D-22 class sub was advanced.

I'm going to weigh in and say that you just won't get away with so many advances so soon. Gradual increments are the way to go.

I could see installing an ASDIC set on a submarine, which makes it a more potent ship when submerged. In consequence, the class might lose the deck gun, or that might have to wait a class or two. Experience then suggests that the mililiter would be a useful fitting to enable prolonged submerged operations, as surfacing is now just making yourself vulnerable. This ship will probably have some early streamlining, but not a huge amount. The hydrodynamics of the hull will have to be improved over time - I can't see a ship like this arriving until 1936 or 1937 at the earliest, and that's probably pushing development some.

You seem to be underestimating the natural conservatism of shipbuilders and naval architects. Normal practice on anything that doesn't need to be changed is to say, "Well, just do whatever we did on the last ship." Also, getting a shipyard to produce the clean hullform you're after without that level of experience might be rather optimistic. Basically, you want very complex, relatively short-radius curvature in a plate which, by necessity, will undergo some pretty severe loading. Sounds like a recipe for trouble to me.

Time to put oil on this fire?

The following is what I was going to post for Greek sub development but here is as good as any. I was going to post the picture as well but I don't have it handy. Many real world developments existed in the inter war period - what stopped them was money.

Greek Submarine Development

Greece started with three French built submarines pre ww1. Greece watched developments during the Dardanelles campaign where a single German submarine forced the withdraw of heavy fire support ships and RN & RAN submarines penetrated the straits and operated against Turkish shipping in the Sea of Mamara. The conclusions were that submarines were a grave threat to a seaborne invasion and only submarines can penetrate the Dardanelles. Greece has largely ignored the war on merchant tonnage as it failed but in the face of defended targets (convoy) by 1918, two out of every three attacks were on the surface at night. With the CT dictating smaller submarines coupled with Greeces need for opposing an invasion force and possible operations in and past the Dardanelles, the submarine staff have eliminated the gun from the needs of a Greek submarine. Post war development started with the aquisition of RN R-Class submarines because they were capable of high underwater speeds (the current in the Dardanelles is about 3 knots from the Black Sea) and they were on the disposal list. The four ex-R class (Hermês Class) were followed by slightly improved versions built locally, the Nemesis class running to twenty two units. The Nemesis replaced the Hermês Class's 6x18" torpedoes with 4 harder hitting 21" topredoes. The high speed submarines are short legged so a series of special transports have been built to move submarines to operational areas. These transorts have also been found to be usefull in carrying the navy's X-lighters (landing craft). Following exercises, a new transport design better suited for both submarine transport and X-lighter transport are to begin construction this year.

Aknowledging that small subs and these transports were not a perfect solution there had been growing calls to build larger submarines capable of transitting on their own power but still capable of the missions expected of the Nemesis class. After years of development the 800 ton Delphinos class subs will start construction this year.



[size=3]S-30 Delphinos, Greek Submarine laid down 1932[/size]

Displacement:
802 t light; 819 t standard; 852 t normal; 878 t full load

Dimensions:
Length overall / water x beam x draught
196.85 ft / 196.85 ft x 21.98 ft x 13.78 ft (normal load)
60.00 m / 60.00 m x 6.70 m x 4.20 m
4 - 21.0" / 533.4 mm submerged torpedo tubes

Machinery:
Diesel Internal combustion generators plus batteries,
2 shafts, 628 shp / 469 Kw = 10.4 kts
Range 3,225nm at 9.00 kts
Bunker at max displacement = 30 tons

Electric motors, 2 shafts, 3000 shp = 12.0 kts submerged
Range 20nm at 11 kts
Battery = 250 tons

Complement:
32

Cost:
£0.860 million (estimate)

Distribution of weights at normal displacement:
Armament: 0 tons, 0.0 %
Machinery: 19 tons, 2.2 %
Hull, fittings & equipment: 569 tons, 66.8 %
Fuel, ammunition & stores: 49 tons, 5.8 %
Miscellaneous weights: 215 tons, 25.2 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
735 lbs / 333 Kg = 6.8 x 6 " / 152 mm shells or 0.8 torpedoes
Stability (Unstable if below 1.00): 1.01
Metacentric height 0.5 ft / 0.2 m
Roll period: 12.8 seconds
Steadiness - As gun platform (Average = 50 %): 1 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 0.00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.500
Length to Beam Ratio: 8.96 : 1
'Natural speed' for length: 14.03 kts
Power going to wave formation at top speed: 34 %
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: 0.10 ft / 0.03 m
- Forecastle (20 %): 0.10 ft / 0.03 m
- Mid (50 %): 0.10 ft / 0.03 m
- Quarterdeck (15 %): 0.10 ft / 0.03 m
- Stern: 0.10 ft / 0.03 m
- Average freeboard: 0.10 ft / 0.03 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 58.7 %
- Above water (accommodation/working, high = better): 0.7 %
Waterplane Area: 2,883 Square feet or 268 Square metres
Displacement factor (Displacement / loading): 338 %
Structure weight / hull surface area: 131 lbs/sq ft or 642 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 4.48
- Longitudinal: 2.82
- Overall: 3.17

Hull space for machinery, storage, compartmentation is excellent
Ship has quick, lively roll, not a steady gun platform
Operating Depth 317ft (225ft subsim)