WesWorld

The Italian anti-submarine effort in the world war did not produce great deeds with no submarines being accredited to Italian surface forces. However, there were only a handful of enemy submarines operating in the Mediterranean during this period. The most useful weapon against them were nets and mines. The weapons fitted to RMI warships were depth charges type 50/1917 with an explosive charge of 50kg and a weight of 66kg. These were fitted to destroyers, some escorts and the new MAS (Motoscafi Anti Sommergibili). The MAS proved to be totally unsuited to anti-submarine work, being too small, having insufficient seakeeping and having very temperamental aircraft engines. They have since been used for other duties. The method for detecting submarines relied on c-tubes, mechanical hydrophones which listened for the sounds made by a submarine, then gave a bearing that the noise was coming from. However, the range was limited and the accuracy of the bearing ± 5°. As such, this method was not particularly successful. The depth charges were launched in patterns of 5 when a contact was acquired: two charges either side from a Y-gun and 3 charges from the stern racks. The first vessel fitted was the destroyer Ardito. 23 vessels had been fitted with this method by the end of the war.



1. RN Ardito



2. Y - gun

Post-war, the first destroyers to be newly built were the Navigatori class. As these were scouts, the anti-submarine function was not considered to be as important. A single rack containing 20 depth charges was placed on the stern, along with the hydrophones.



3. RN Giovanni da Verrazzano

The next major development was the Type 115 asdic acquired from the Royal Navy. This used an active system which transmitted a sound and then listened for the echo. The Type 115 was a modified version of Type 114 produced in 1923 to sweep a 180° arc before switching to a localising mode of 5° arc. It had an electrical training mechanism but the system failed to reach acceptable standards in the RN, and was abandoned during the 1920s. One reason for this was its fixed but streamlined steel dome, which limited the ship’s speed to 20 knots, as it crushed above that speed. This set was fitted to the Turbine Class destroyer Aquilone and extensive tests were conducted. The anti-submarine armament remained a single depth charge rack on the stern. As stated above, the system was not successful as it limited the ship's speed to 20knts. The dome was strengthened and streamlining increased until it was possible for maximum speed to be attained.

The next 3 classes of destroyer continued with the world war period anti-submarine equipment. Two new depth charges were introduced in 1927, the 50/1927 and 100/1927 respectively with differences being in weight of explosive. Depth charge projectors of 430mm diameter were included on the destroyer Baleno which increased the pattern size.



4. RN Baleno



5. 430mm projector

There was then a pause in the construction of destroyers which allowed the anti-submarine technology to mature. The next class of destroyers, the Soldati were to be the first to mount all the new systems together.

Mention at this point must be made of the 4 Vespa class corvettes. Their slow speed of 20knts meant that the unmodified Type 115 (named D1 in Italian service) could be fitted. This was alongside 8 x 430mm projectors aft and a single towed torpedo at the stern. 200Hp electric creeping motors were also put in place for silent running at 5knts. The 430mm projectors aft faced towards the either beam of the ship and were loaded with 2 x 50/1927 each. Upon acquiring the target with the D1 sonar, at about 200m range the ship would turn right and fire 8 depth charges in 2 square patterns, one at 100m depth and one at 50m depth. The same attack could then be made with the projectors on the other beam and the torpedo towed through the target area afterwards.



6. RN Vespa

The pause in destroyer construction was taken as an opportunity to improve on the D1 system with the result being the D2bis. This was a thoroughly modern and mature system, with a loudspeaker on the bridge, mechanical range indicator, electric training from either sonar hut or bridge and capable of automatic transmissions. It could also have training returns fed in to the system to allow own ship training at sea. The dome was strong and did not slow the ships, and was not retractable. The range was improved over the D1 with 2000m maximum on trials with an error of ± 1°. The sweep range was increased to 360° but the local mode remained 5°.

The next class of destroyers laid down in 1931, the Soldati class, featured the D2bis system and improved weapons systems as well. Two Gatteschi dischargers were installed aft, which were equipped with six 4-charge trolleys each, which upon command could be dropped into the water. This armament allowed for the contemporaneous dropping of patterns of 8 bombs for a total of 400 kg of explosive which made a “pocket” around the submarine under attack. Inside each group the bombs were set to explode at a different depths (30, 60, 90 and 120 meters) to create a vertical pattern. It was possible to launch all 48 weapons at once creating a 3D pattern around the submarine. Two 430mm dischargers were included on each beam with 8 bombs stored in racks close by. There was a single Ginnochio towed torpedo on the stern. To take advantage of the range of the new D2bis system various ideas were explored in order to fire a weapon whilst the submarine was still detectable. Two units of the Soldati class were altered with each receiving a different experimental weapon. Ascari received two launchers either side of the bridge. The launcher holds 12 rockets with each with a 15kg contact charge. The two launchers create two concentric circles about 500m in front of the ship. Aviere received the new 325mm torpedo. The weapon was modified from standard, being off-balance to create a downward spiralling motion. The launching mechanism, which has created some problems in experiments, consists of stub wings with 2 small rockets which give a range of 1000m. Tests with both these experimental weapons are still ongoing and have yet to be proven viable for use on a destroyer-sized vessel.



7. RN Aviere



8. Gatteschi discharger

Cool text, RA. Thanks for sharing.

I wonder how much of it is historical and what is ahead of times. For examples I think you´re stretching things a little bit (too much?) with all these rocket things. A rocket launched torpedo and a hedgehog-like launcher?

I like the idea of sharing technology even though I can´t say if sharing ASDIC technology by the British is realistic....

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I like the idea of sharing technology even though I can´t say if sharing ASDIC technology by the British is realistic....

I did say "acquired" from the Royal Navy. The D2 set of sonar is a historical Italian design from 1930/31. I added the bis and came up with a system like the RN Type 119 of the same period. Just making it more accesible with the loudspeaker on the bridge and automatic transmission.

What isn't historically correct. The bit about the 325mm rocket-launched torpedo, which won't be put into service until it gets onboard sonar in 1940s. The rocket launcher similar to Hedgehog/mousetrap is a few years ahead of time but I think its a relatively easy step. The rockets are just easier and more flexible than a spigot mortar. Easier to fit a different charge to control range and easier to fit different warheads, smoke or parachute flares.

In addition to the points already brought up, why the urgency to develope such weapons. Did Italy suffer against enemy Subs as badly as the British did?

Still, a nicely done peice of writing.

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G. Updated Order of Battle for France, 1 April 1931

Note: Y)+Z = completed (under repair/refit) + under construction

BB: 6(2)+2
BC: 0(0)+0
CV:2(0)+1
CA: 6(0)+0
CL: 22(0)+0
Monitors: 5(0)+0
DD: 96(0)+0
Sloops: 0(0)+0
Fleet Submarine: 15(0)+0
Coastal Submarine: 70(0)+0

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F. Updated Order of Battle for India, 31/3/31

Note: Y)+Z = completed (under repair/refit) + under construction

Battleships (BB): 3(0)+1
Aircraft Carriers (CV): 1(0)+0
Heavy Cruisers (CA): 5(0)+0
Light Cruisers (CL): 13(0)+0
Destroyers (DD): 32(0)+2
Submarines (SS): 22(0)+1

Quoted

At the end of this quarter the RSAN consists of (units in service only):

48 ASW launches
24 motor launches
37 minesweepers
56 small patrol crafts
80 TB/DDs (does not include 11 TBs with 15cm guns)
37 cruisers category b (include 11 TBs with 15cm guns)
7 cruisers category a
14 capital units
5 costal defence ships
2 fleet carrier
48 submarines category b
32 submarines category a

Why put India in there? Compared to the other two nations you mentioned, its submarine force is rather small (even smaller than the Italian one) and at some distance from the Mediterranean. South Africa, too, is a long distance from Italy and I doubt it has interests in the mediterranean. A majority of the RSAN's subs will remain in the southern hemisphere. Only France is the real threat to Italy and it's not that big... only about twice as big as the Italian sub fleet.
:-)

BTW, Japan at an even greater distance:
Updated Order of Battle, 3/31/31

Limited warships:
Battleships: 9(0)+0
Aircraft Carriers: 4(0)+0
Heavy Cruisers: 9(0)+0
Light Cruisers: 21(0)+23
Destroyers class 1: 0(0)+0
Destroyers class 2: 62(0)+0
Submarines: 126(0)+61
Coast Defense Vessels: 12(0)+0
Training carrier: 0(0)+1

... and to think that Japan had only 7 subs on 12/31/1929.

Why put India and SAE there? Because of treaty obligations with other countries, namely The Netherlands and Denmark. Italy might not be able to deploy battleships over to SEA in case of an emergency, but there are some other ways in which Italy can help. India's forces might be small, but they are in a good strategic position.

I can see the point that the sub threat now is fairly high, but Italy seemed to jump to the task fairly quickly after WW1 with a mere fraction of British losses atributed to subs.

It just seems odd coming off the heels of the insinuation that only two nations posses ASDIC in Wesworld when two additional countrys were draged into the war via sub losses.

To be fair I don't think its a stretch for Italy to be lightly concerned about SAE/Indian subs with the EAS sitting in their backyards.

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I can see the point that the sub threat now is fairly high, but Italy seemed to jump to the task fairly quickly after WW1 with a mere fraction of British losses atributed to subs.

The bit about WWI and post-war is historically accurate. I imagine that France was the main driving force in OTL as in ATL.

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It just seems odd coming off the heels of the insinuation that only two nations posses ASDIC in Wesworld when two additional countrys were draged into the war via sub losses.

Which countries btw? I must add that I was wrong before. The count should be three countries, UK, USA and Italy (maybe others haven't found anything) but the USA set is best described as inferior.

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To be fair I don't think its a stretch for Italy to be lightly concerned about SAE/Indian subs with the EAS sitting in their backyards.

Who cares about the SAE/Indian subs and the EAS when the much closer FAR has this:

France
Fleet Submarine: 15(0)+0
Coastal Submarine: 70(0)+0

Atlantis
Fleet Submarine: 20(0)16
Coastal Submarine: 72(0)0

Russian Federation
Fleet Submarine: 30(0)+0
Coastal Submarine: 130(0)+10

Total
Fleet Submarine: 65(0)+16
Coastal Submarine: 272(0)+10

... compared to AANM...

Iberia
SUB = 32 (0) + 8/0 (0)

Denmark
Submarine a: 8(0)+0
Submarine b: 11(0)+0

Italy
Submarine a: 22(0)+0
Submarine b: 29(0)+8

Netherlands
Fleet Submarine: 20(0)0
Coastal Submarine: 15(0)3


Total
Fleet Submarine: 50(0)+0
Coastal Submarine: 54(0)+11

Iberia not known but as you can see, while the differences between the large subs is not that big, there's a huge difference between the coastal subs of FAR and AANM.

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Originally posted by Red Admiral
Which countries btw? I must add that I was wrong before. The count should be three countries, UK, USA and Italy (maybe others haven't found anything) but the USA set is best described as inferior.

I've always maintained that Atlantis entered the war due to submarine losses ala a Lusitainia type incedent and subsequent war losses.

IIRC the SAE also entered under similar surcumstances.
Maybe I miss-understood the comment about who had/should have ASDIC but to me it wouldn't seem like a stretch for a highly industrialized nation like Atlantis to also possess a similar device.

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Originally posted by Rooijen10

Who cares about the SAE/Indian subs and the EAS....

Thats why I said lightly concerned.

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Originally posted by Rooijen10
.....when the much closer FAR has this:

France
Fleet Submarine: 15(0)+0
Coastal Submarine: 70(0)+0

Atlantis
Fleet Submarine: 20(0)16
Coastal Submarine: 72(0)0

Russian Federation
Fleet Submarine: 30(0)+0
Coastal Submarine: 130(0)+10

... compared to AANM...

Iberia
SUB = 32 (0) + 8/0 (0)

Denmark
Submarine a: 8(0)+0
Submarine b: 11(0)+0

Italy
Submarine a: 22(0)+0
Submarine b: 29(0)+8

Netherlands
Fleet Submarine: 20(0)0
Coastal Submarine: 15(0)3


Total AANM
Fleet Submarine: 50(0)+0
Coastal Submarine: 54(0)+11

Total FAR
Fleet Submarine: 65(0)+16
Coastal Submarine: 272(0)+10


Iberia not known but as you can see, while the differences between the large subs is not that big, there's a huge difference between the coastal subs of FAR and AANM.

Close to half the coastal sub tally is French. Their are quite a few elderly coastal subs in the Atlantean fleet.
Keep in mind FAR has two top teir CT nations in its makeup, it should possess more hulls anyway. As you said, France is the only dirrect threat sub wise, something alliance tally numbers would exagerate.

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I've always maintained that Atlantis entered the war due to submarine losses ala a Lusitainia type incedent and subsequent war losses.

IIRC the SAE also entered under similar surcumstances.

What if there were Atlantean and South African citizens aboard the Lusitania itself? And unlike the US who remained neutral, Atlantis and South Africa did enter the war after that particular incident.

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Thats why I said lightly concerned.

And I said "who cares". :-)
(gravestone text: "He cared not for the other enemies who came in and crushed the empire while he was paying too much attention to the aggressions of the next door neightbour.")

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Close to half the coastal sub tally is French.

Looks more like a quarter to me.

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Their are quite a few elderly coastal subs in the Atlantean fleet.

Depends on what you call 'elderly'. What I would consider 'elderly' is a Hunley type submersible with a towed torpedo.
^_^

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Keep in mind FAR has two top teir CT nations in its makeup, it should possess more hulls anyway.

More hulls = more submarines = bigger threat.

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As you said, France is the only dirrect threat sub wise, something alliance tally numbers would exagerate.

Well, Atlantis is not that far away (at least much closer than SA and India), and part of the Russian Fleet has an exit to the Mediterranean...
Perhaps the numbers exagerate the situation... perhaps not... It depends on how you look at it, and Italy probably looks at the threat as a whole.

That is what I thought RA was up to in the Vespa Class, an enhanced DCT for bracketing subs in a box of DCs. It's a good idea. The rockets are more like the Soviet RBU series and may be ahead of the times but are basic rockets. In the 1930s research began into artillery rockets and so I reckon he is not too far ahead of history. The Med is poor for subs and new methods to destroy them are better than, say, the RN WW2 experience in the early 1940s of just using basic DC and hoping to guess the correct depth. I don't think the 325mm torpdeo will hit anything, but it's a stepping stone to acoustic homing torpdoes.

The rockets are DEFINITELY ahead of time, a spigot mortar would be more realistic if any ahead-thrown weapon for ASW is realistic in 1930-31. Without wartime experience with active sonar and manuevering targets, though, I have real doubts that ahead-thrown weapons would be seen as needed, they weren't in OTL after all.

Considering the RN introduced ahead throwing weapons in 1917 then tried to do the same again in the mid-20s, I don't think Italy is too far off the mark.

Not sure about the rockets. Solid fuel similar to UP isn't too difficult. Actually UP is basically exactly what I want, but with a larger warhead and not as much range.

Solid fuel might well be the critical factor here.

As I understand it you want to have your projectiles fly (with rocket power) to a certain point ahead of your ship where they arrive in an exact pattern. To achieve this you need fuel that burns controlled and exactly the way you want it. So you need quite some experience for such a weapon with such kind of fuel.

On the other hand you don´t need this constancy (the way the fuel burns) for weapons like UP batteries where your projectiles just fly as high as possible to lift a cable with an explosive charge. It doesn´t matter if the fuel of one rocket burns longer than the other. You don´t need a specific pattern with little divergence from what was intended.

So I think your rocket powered hedgehog is indeed ahead of times.

I also think that the originial hedgehog had no rocket powered procetiles. IIRC, the projectiles were "shot" ahead of the ships bow and had no rocket engine etc.

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Originally posted by Rooijen10
What if there were Atlantean and South African citizens aboard the Lusitania itself? And unlike the US who remained neutral, Atlantis and South Africa did enter the war after that particular incident.

Its possible, without a detailed timeline of the war (which would take up lots of spare time) its left to speculation.

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Originally posted by Rooijen10 Looks more like a quarter to me.

My bad, I was refereing to Russia not France.

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Originally posted by Rooijen10 Depends on what you call 'elderly'. What I would consider 'elderly' is a Hunley type submersible with a towed torpedo.

Elderly in the sence of range, armament and diving depth. Coastal subs are not the real threat unless they are from a neighbouring country that shares borders. The real threat is lingering fleet subs who can loiter and hit multipull targets.

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Originally posted by Rooijen10 More hulls = more submarines = bigger threat.

Then Japan would certainly be on peoples SONAR displays with their SUB expansion program

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Originally posted by Rooijen10 Well, Atlantis is not that far away (at least much closer than SA and India), and part of the Russian Fleet has an exit to the Mediterranean...
Perhaps the numbers exagerate the situation... perhaps not... It depends on how you look at it, and Italy probably looks at the threat as a whole.

Presisely why they would consider SAE and Indian sub fleets, particularily when they can threaten Italian interests abroad.

I feel I also need to mention that French territory's are even more spread out compaired to Atlantis or Italy. With territory's in practically every theatre ships of all types get distributed quite quickly.

Well if I go ahead as planned Nordmark might build a few more subs, just 10 is a bit too few.

On the other hand Nordmark is gonna start building Frigates like the clappers.

Lol... the clappers!

You think you need Frigates, look at the Atlantean tally....A big fat 0 .