The Real Sparviero Aircraft Carrier

[archipeppe]

Italian Navy during WWII started the conversion of the two almost-sister ocean liners ROMA and AUGUSTUS (they had only different engines), they was turned into AQUILA and SPARVIERO.
While the AQUILA was pratically finished (even if not still entered in service) when Italian signed the Armistice with Allies, the SPARVIERO was only an leftover hull in Genoa's mooring port.

AQUILA aircraft carrier has a vast an qualified iconography, photos, drawings and blueprints that depicts the ship with high level of fidelity, unfortunately for SPARVIERO only some photos of the hull are available and no more about its final layout.
Said that all the drawings that currently it is possible to find on Internet about SPARVIERO's layout are wrong or, more correctly, they not represent the final and real design of the ship, since they are related to the original project of ROMA/AUGUSTUS conversion drafted back to 1936.

In the two authorative books:
- A. Rastelli "La portaerei italiana, cento anni di dibattiti e progetti" (Mursia, 2001)
- M. Cosentino "Le portaerei italiane" (Albertelli Edizioni Speciali, 2011)

the SPARVIERO final layout, dated back to January 1943, is well described, as follows:
Lenght: 216,65 mt
Width: 34 mt (bulges)
Lenght: 180 mt (flight deck)
Width: 25 (flight deck)
Mass: 28,000 tons
Aircrafts: 35 Reggiane 2001 OR
Weapons: 8 x 135/45, 12 x 65/64, 24 x 20/65 (A.A. maching guns in group of 6)

Furthermore the ship would have a small island, an hurricane bow, a couple of German catapults, four arrest cables.

Starting from such info I decided to try to reconstruct the most likely design of SPARVIERO, in doing that I helped myself with the AQUILA design of June 1941 (U.P. 188 Progetto Bozzoni) and with the postwar proposal to convert the cruiser TRENTO hull into a small aircraft carrier for Spain (Proyecto N. 65 dated 1949).

This a speculative design but for sure more representative of all 1936 drawings, of course I'm willing to modify/update it if and when new documented info will be available.

 

[Hardrada55]

Where's the stack(s)?

 

[archipeppe]

Where's the stack(s)?

They are placed on both sides, below the flight deck sporting just after the first elevator, since the small island has no funnels, so remained where they were placed in the original 1936 design.

 

[Kugelblitz]

Having that much non-deck aft seems weird (the 20mm guns are clearly larger than to scale, but makes it look even weirder)

 

[archipeppe]

Having that much non-deck aft seems weird (the 20mm guns are clearly larger than to scale, but makes it look even weirder)

I agree that it seems odd but it is clearly visibile in the (scarce) photography of the hull, taken just before the Armistice.
It is possible to see the new bow (slightly longer) and spot the aft-deck deliberately left the same as the ocean liner (and it also was in the 1936 design).





The AA gun system is in the correct scale, it was a huge 6 barrels Breda 20/65 RM system, with 3 crewmember, hydraulic system stabilized, the very same envisioned for AQUILA, here it is a photo of one prototype taken at Breda premises during 1943.

 

[Nick Sumner]

Is there any more information on the six barrelled Breda 20/65 RM system ?

 

[archipeppe]

Is there any more information on the six barrelled Breda 20/65 RM system ?

The most authoritative source (in English) is the book by D. Jabes and S. Sappino "Aircraft Carrier Impero: The Axis Powers' V-1 Carrying Capital Ship" (Fonthill Media, 2018), where is briefly described with its main performances (220 rpm each barrel and 5.000 mt of range).

Aircraft Carrier Impero: The Axis Powers' V-1 Carrying Capital Ship: Davide Jabes, Stefano Sappino: 9781781556771: Amazon.com: Books

Aircraft Carrier Impero: The Axis Powers' V-1 Carrying Capital Ship [Davide Jabes, Stefano Sappino] on Amazon.com. *FREE* shipping on qualifying offers. <SPAN STYLE= >From late 1941 Italy had been developing a secret project with her German allies to move the V1 wunderwaffen aboard aircraft...

www.amazon.com

Anyway, as follows, another couple of images of one prototype (slightly different from the first picture):

 

[archipeppe]

The next image comes from Cosentino's book and depicts the rear deck of SPARVIERO, it is clear that the back part of AUGUSTUS was left for good while all the other upper structures were simply thorn away.

 

[Kugelblitz]

If they're to scale (they still seem big to me), it's even weirder. Any chance that the aft deck was meant to be removed, but they they hadn't got there yet?

tnx for pictures! hadnt seen the sextuble or the aft close up before

 

[archipeppe]

If they're to scale (they still seem big to me), it's even weirder. Any chance that the aft deck was meant to be removed, but they they hadn't got there yet?

tnx for pictures! hadnt seen the sextuble or the aft close up before

As Said before there are a couple of key elements about the free aft deck:
1.such feature was present also in the original 1936 design
2.the flight deck lenght in the 1943 design is 180 meters, if you start from the bow and walk back to aft, you can count 180 meters exactly in the point where start the free aft end.

 

[archipeppe]

This the 1936 design

 

[archipeppe]

My guess is that the aft deck was left intentionally in this way, since the SPARVIERO's hull has already left the drydock with the new bow, the added bulges (partially filled with concrete as also for AQUILA) and the aft deck as the original AUGUSTUS.
After that the hull received a temporary superstructure with a couple of A.A. Flak guns for a minimum of protection.
SPARVIERO was moored to "Calata Oli Minerali" (Mineral Oil Dock) in the port of Genoa, near the unfinished crusier CORNELIO SILLA (belonging to the CAPITANI ROMANI class) which gave its engines to AQUILA, and partially covered by a fake flight deck in order to be disguised as a small aircraft carrier by Allied reconeissance.

I enclose a my artwork in order to clarify better the concept.

 

[archipeppe]

This was the port of Genoa during 1938, not that much different by 1943.

 

[archipeppe]

I tried to figure out the 3d look of SPARVIERO with such pencil hand drawing of mine.

 

[Nick Sumner]

Archipeppe, thank you for the information on the six barrelled Breda 20/65 RM system!

 

[archipeppe]

Archipeppe, thank you for the information on the six barrelled Breda 20/65 RM system!

You are welcomed my dear Nick, and "RM" stands for "Regia Marina" of course, since such behemot was explicitly conceived to defend the fleet from air attacks.

 

[archipeppe]

The Breda 20/65 Mod. 1935 was really a general purpose gun, widely exploited by all the Italian armed forces (and not only by them),
Regia Marina normally used the various Mod.35 RM (twin barrel), Mod.39 (single barrel) and Mod.40 (single barrel).

The six-barrels version (hydraulic gyroscopic stabilized) was expressely developed to protect the various Aircraft Carriers and maybe also for Super-Dreadnough (LITTORIO class) in the 1943-45 timeframe and never become available due to the Armistice.
Both AQUILA and SPARVIERO were armed with some 20mm German Flak cannons in order to provide some A.A. temporarily defence.

Breda 20/65 mod.35 - Wikipedia

en.wikipedia.org

 

[Tzoli]

The Regia Marina were also interested in a larger fully enclosed quadruple-twin mount of 8 barrels and own integrated director/rangfinder:

Intended mostly for the new cruisers.

 

[archipeppe]

This was the Port of Genoa in April 1945, and it is possible to see the final position of both AQUILA and SPARVIERO's hull just before the end of War in Europe.
The drawing was elaborated by several photos taken by Allied aerial reconeissance, and it is part of the following document:

The Sinking of the Italian Aircraft Carrier "Aquila" A Controversial Question
Achille Rastelli and Erminio Bagnasco
Warship International
Vol. 27, No. 1 (1990), pp. 55-70

 

[Kugelblitz]

Thanks a lot Archipeppe. In the 1936 Sparviero (and all other carriers ever to my knowledge) nothing protudes above the flight deck abaft the flight deck. Thats whats so puzzling about the 1943 version.

Thanks Tzoli for the octuble. Any idea what the weight of that contraption was?

 

[archipeppe]

Thanks a lot Archipeppe. In the 1936 Sparviero (and all other carriers ever to my knowledge) nothing protudes above the flight deck abaft the flight deck. Thats whats so puzzling about the 1943 version.

Yes, you are right.
As said first my actual drawing is based upon the (scarce) information available about the final January 1943 design of SPARVIERO, that (at this point) we know is rather different by the original 1936 proposal (that was for both AQUILA and SPARVIERO).
There are two possibilities:
1) I misintepreted the info and I placed in the wrong position the 2 6 barrels gun units.
2) Since even in the 1936 design were present a couple of A.A. gun (not sporting but anyway they are there) the Regia Marina or Ansaldo (or both of them) decided to leave it in that position also the new 6 barrels gun units, even if they sporting.

There is also another possibility, since originally the SPARVIERO was conceived first as anti-submarines carrier (equipped with a bunch of IMAM Ro. 63), later only as only to launch aircraft but not recovery them (as also for the BOLZANO proposal) and only at the end Regia Marina decided to have a full fledged carrier with 35 Reggiane Re 2001 O.R., maybe the A.A. evinsioned remained the same as the first proposal. or at least this is my guess about it.

Taking into account that the rear deck was intentionally left as the original AUGUSTUS liner, there are no chances to have barbettes sporting on both sides of the stern.
So or they was placed on the deck (as in my drawing) or they were placed forward in other position or in additional barbettes (also not so likely since both flanks of the ship were already crowded by the other armaments barbettes).

Anyway the two 6 barrels gun unit, even if they are currently sporting, placed at the very both sides of the flight deck, should not affect the landing path of the approaching aircrafts.

In absence of hard data, the topic remained open.
As also said first I will modify or update my artwork in case more well referenced info will (if any) available.

In any case my artwork is still more representative of the January 1943 desing than any other one derived by the 1936 one, since all the main elements (180 mt flight deck, small island, hurrican bow, catapults and all the right armament) are in place.

 

[Tzoli]

Sorry I don't have any technical info about that mount only that it's size is roughly the size of the 90mm Single mount as evident on the Costanzo Ciano class Cruiser design:

 

[archipeppe]

I found that there is some point of contact among the SPARVIERO final design and the Japanese AKITSU MARU.
Both of them were passenger liners later converted into aircraft carriers, and share more or less the same architecture (even if the AKITSU MARU was smaller than the AUGUSTUS/SPARVIERO).
Both of them had free stern deck housing A.A. armament, both had the original hull more or less untouched, and both had the flight deck up to the bow, both had a minimal island (even if the Japanese design had also the funnel).

I think that the AKITSU MARU design (and his sister ship NIGITSU MARU) could be regarded as good reference of the final SPARVIERO design.

Japanese aircraft carrier Akitsu Maru - Wikipedia

en.wikipedia.org

 

[Kugelblitz]

Akitsu Maru was not intended to land aircraft, and a lengthening of the deck was planned to enable her to, when she was sunk. That does not in any way imply, that this was the case for Sparviero as she was so much larger that deck space for landing was not a problem.

 

[ptdockyard]

Before he passed away, Stefano Sappino mentioned to me that he had seen something showing the Spaviero in a similar configuration. The design with the narrow take-off "balance beam" never made sense to me and this thread is a gem! Thank you for your great work.

Dave G

 

[DWG]

The track system on deck leading from the lifts to the catapults suggests that she uses the same inefficient launch system proposed for the Graf Zeppelin, where aircraft are loaded onto launch trolleys in the hangar, then wheeled along the tracks to the catapults and launched in the same manner as seaplanes, rather than launching on wheels as in the allied and Japanese carriers.

 

[archipeppe]

Before he passed away, Stefano Sappino mentioned to me that he had seen something showing the Spaviero in a similar configuration. The design with the narrow take-off "balance beam" never made sense to me and this thread is a gem! Thank you for your great work.

Dave G

You're welcomed Dave. too bad that Stefano passed away his work as a real sleuth about Italian aircraft carriers development will really miss.
The fact that he saw something like my artwork assure me that I'm on the right track.
My assumption is that there were for sure consolidated design documents of the real Sparviero when Ansaldo started to work around the Augustus' hull.
Such documents are assumed to be lost during the war, but this is really true?

My hope is that something survived the war and, maybe, what that something that Stefano saw.
Once recovered such documents we will be able to address a real design the Sparviero, rather than the odd (and frankly unbelieveble) "balance beam" in the 1936 design.

Best regards
Giuseppe

 

[archipeppe]

The track system on deck leading from the lifts to the catapults suggests that she uses the same inefficient launch system proposed for the Graf Zeppelin, where aircraft are loaded onto launch trolleys in the hangar, then wheeled along the tracks to the catapults and launched in the same manner as seaplanes, rather than launching on wheels as in the allied and Japanese carriers.

Correct.

Even if Germans provided only a couple of DEMAG catapults to AQUILA and they came by the incompleted GRAF ZEPPELIN.
So even if Ansaldo managed to complete the SPARVIERO it would be rather difficult, if not impossible, to get other catapults by Germans.
This implies that SPARVIERO should necessarily use the same catapult exploited by the old MIRAGLIA during the trials conducted with the Re 2000, and with all its limitations.
Otherwise SPARVIERO would attend some newly developed Italian catapult, but honestly I didn't found any clue about it.

 

[archipeppe]

And this is the Gagnotto type catapult used onboard the GIUSEPPE MIRAGLIA to launch both IMAM Ro-43 hydro and the Reggiane Re-2000 "Catapultabile".

 

[archipeppe]

Of course the same "Gagnotto-Bargiacchi" catapult was used onboard the Littorio class superdreadnough, with the possibility to launch both Ro-43 and Re-2000.
So even in case of German denial, there was possible to embark onboard the SPARVIERO at least a couple of Italian-built catapults (even if for sure less effective, considering that the Re-2001 was heavier than the Re-2000).

 

[archipeppe]

Just to be sure that the Gagnotto-Bargiacchi catapults were effective also with the Reggiane Re-2001, just before the Armistice the Regia Marina has planned to replace both Re-2000 cat and IMAM Ro-43 with Re-2001 cat and FIAT G-50B two seat reconeissance fighter (2 Re-2001 and 1 G-50B), onboard the LITTORIO class warships.

 

[archipeppe]

A rare photo showing a Re 2000 Cat about to be launched through a Gagnotto-Bargiacchi catapult onboard one Littorio class battleship.

 

[MJBurmaster]

Yes, Stefano could really have helped on questions. My question concerns the mercantile construction and what if anything was done internally to enhance protection, givven the usual problems with merely cementing additional plate to enhance protective qualities. Was this a case where given the design that stiffening wherever possible took place, or some scheme to put in runs of splinter armour ?

 

[archipeppe]

Yes, Stefano could really have helped on questions. My question concerns the mercantile construction and what if anything was done internally to enhance protection, givven the usual problems with merely cementing additional plate to enhance protective qualities. Was this a case where given the design that stiffening wherever possible took place, or some scheme to put in runs of splinter armour ?

Interesting point.
Honestly I don't know if Ansaldo has designed any internal protection of SPARVIERO.
Hard data are about only two things:

1) the usual bulges added and partially filled with concrete as passive protection against torperdoes run (as also for AQUILA)
2) Ansaldo evnisioned an armoured flight deck for SPARVIERO (unlike AQUILA which its flight deck lacked of any protection)

Any serious research must start from the above assumptions.

 

[archipeppe]

Here it is a rare image of SPARVIERO's bow, shortly after being seized by Germans.
Behind it is visible the CORNELIO SILLA hull with the double deck to disguise it as small aircraft carrier.

 

[MJBurmaster]

Given the constraints of mercantile design, it is hard to vizualize good armouring except splinter armour here and there in most useful areas. But the armoured deck in of itself should not require largescale redoing of the ship, stiffening girders and such would do the trick.
As to the bulging, however, I really don't recall what type was contemplated. Certainly not Pugliese, right, which would have delayed construction. Was it multi-layer or tubes and with the concrete filing you suggest? But even then seems you have a rather inelastic system whch defeats the whole notion of effective defense against underwater explosions, unless the concrete is extraordinary in thickness for a ship of such size.

 

[archipeppe]

Both AQUILA and SPARVIERO had the bulges partially filled with concrete, no Pugliese system at all, mainly for stabilization reason (in order to bring down the CoM), and after to provide some degree of passive protection against torpedoes (with all the limitation that MJBurmaster has already pointed out).

The Pugliese system was different since it was embedded within the hull of the ship after conversion (e.g. GIULIO CESARE and CAIO DULIO) or by project (LITTORIO class).

As follows I enclose the SPARVIERO project cross section published in Cosentino's book (drawing by A. Nani), that I exploited to realize my artwork:


And just for comparison here it is a cross section of the Pugliese System:

 

[MJBurmaster]

Does Cosentino have a sketch of the hull other than in the vicinity of the boiler rooms?

Also, I trust that the waterline mark is at either standard or full load, given a torpedo is running many feet below the warterline and of course is (optimistically) to hit the biggest portion of the bulge.

I assume the plates thickness in the bulge are in metric values. The system is somewhat rigid if one adds up the plates which equals 90mm. Any explanation?

 

[archipeppe]

Does Cosentino have a sketch of the hull other than in the vicinity of the boiler rooms?

Unfortunately not, since this is the only SPARVIERO's drawing available in his book.

Also, I trust that the waterline mark is at either standard or full load, given a torpedo is running many feet below the warterline and of course is (optimistically) to hit the biggest portion of the bulge.

Correct, the waterline is intended as standard load.

I assume the plates thickness in the bulge are in metric values. The system is somewhat rigid if one adds up the plates which equals 90mm. Any explanation?

Since the drawing lack of any scale indication, I also assume that it should be metric because in Italy, especially before and during WWII, the metric system was the only one adopted by Italian state.

 

[Hood]

30 mm = 1.18 inches
90 mm = 3.5 inches
Actually if you look closely at the diagram the middle '30' has little arrows to both the inner bulkheads to the right and left, so the total would be 120 mm = 4.7 inches
That does feel rather thick as a total figure, that would put it thicker than most torpedo defence systems of the era, even for capital ships.
If the larger empty compartment between the steel 'boxes' (formed by two outer faces of 30mm plating) are then filled with concrete it would be an extremely rigid and dense torpedo defence system. Not sure what the effect of a torpedo warhead hitting it would be, the direct explosive effect would be contained but the shock effects would be very damaging.