View source for 100 mm/47 O.T.O. Mod. 1928 (100 mm)

[[File:100 mm-47 O.T.O. Mod. 1928.jpg|thumb|x250px|Triple-turret battery of the [[100 mm/47 O.T.O. Mod. 1928 (100 mm)|100 mm/47 O.T.O. Mod. 1928]] on [[RN Eugenio di Savoia]]]]
== Description ==
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The '''100 mm/47 O.T.O. Mod. 1928''' is an Italian naval gun. It serves as a secondary multi-purpose gun in open twin-gun turrets on a number of Italian cruisers. Being a relatively old design, it struggles with rate of fire and the damage inflicted by an individual shell. But overall it offers an important component of the anti-air defence for the cruisers, being able to engage bombers even a few kilometres up when controlled by the AI gunners.

=== Vehicles equipped with this weapon ===
<!-- ''List out vehicles that are equipped with the weapon.'' -->

* {{Specs-Link|it_cruiser_bartolomeocolleoni_1940}}
* {{Specs-Link|it_cruiser_bolzano}}
* {{Specs-Link|it_cruiser_garibaldi_class_abruzzi}}
* {{Specs-Link|it_cruiser_eugenio_di_savoia}}
* {{Specs-Link|it_cruiser_zara_class_pola}}
* {{Specs-Link|it_cruiser_montecuccoli}}
* {{Specs-Link|it_cruiser_trento}}
* {{Specs-Link|it_cruiser_zara_class}}

== General info ==
<!-- ''Tell us about the tactical and technical characteristics of the cannon or machine gun.'' -->

=== Available ammunition ===
<!-- ''Describe the shells that are available for the weapon and their features and purpose. If it concerns autocannons or machine guns, write about different ammo belts and what is inside (which types of shells).'' -->

{{:{{PAGENAME}}/Ammunition|100 mm HE Dirompente, 100 mm HE-TF Contro-aerea, 100 mm APHE Perforante}}

=== Comparison with analogues ===
<!-- ''Give a comparative description of cannons/machine guns that have firepower equal to this weapon.'' -->
Comparing to the foreign equivalents of a similar calibre the 100 mm/47 O.T.O. Mod. 1928 is rather underwhelming weapon, showing its age when matched against more modern counterparts. For starters, it lacks {{Annotation|HE-VT|High-explosive variable time fuse}} shells that its British and Soviet equivalents have access to, and thus it offers a much lower anti-air potential with its plain {{Annotation|HE-TF|High-explosive with time fuse}} shell. The filler in the high-explosive shells is also one of the lowest, thus being limited in the amount of damage done. This is made worse by a very low rate of fire (owning it to a fully manual operation of the gun by the crew), low targetting speed and a low muzzle velocity. In fact, the gun suffers from having a low reload rate even compared to the variant of the same gun found on the Soviet ships, designated [[Minizini (100 mm)|Minizini]].

There are two upsides however: unusually for the calibre (and owning it to the dated design), the gun comes with a dedicated {{Annotation|APHE|Armour-piercing high-explosive}} shell that can penetrate the hulls of most destroyers and even a number of cruisers, though a low number of guns and the inaccuracy of the AI gunners against bluewater ships make it an unlikely mean of sinking enemy warships. The other saving grace of these guns is their long range, similar to the foreign equivalents, which allows them to harass enemy bombers long before they get ready to drop their bombs, thus discouraging enemy from attempting engagement.

==== HE ====
{| class="wikitable sortable" style="text-align:center" width="100%"
|-
! colspan="2" rowspan="2" |Cannon
! rowspan="2" |Ammo
! rowspan="2" |Calibre<br>(mm)
! rowspan="2" |Muzzle Velocity<br>(m/s)
! rowspan="2" |Sustained rate of fire<br>(rounds/min)
! colspan="2" |Targeting speed<br>(°/s)
! rowspan="2" |TNT Equivalent<br>(kg)
! colspan="2" |Penetration<br>@ 0° Angle of Attack (mm)
|-
!Horizontal!!Vertical!!1,000 m!!5,000 m
|-
|[[File:Kingdom Italy flag.png|link=|25x25px]]
| '''100 mm/47 O.T.O. Mod. 1928''' || HE || 100 || 850 || 9.6 || 11 || 6 || 1.3 || 17 || 17 
|-
|[[File:USSR flag.png|link=|25x25px]]
| [[Minizini (100 mm)]] || HE || 100 || 800 || 12 || 11 || 6 || 1.24 || 45 || 26
|-
|[[File:USSR flag.png|link=|25x25px]]
| [[100 mm/70 SM-5-1 (100 mm)|100 mm/70 SM-5-1]] || HE || 100 || 1,000 || 15 || 14 || 14 || 1.94 || 24 || 24 
|-
|[[File:USSR flag.png|link=|25x25px]]
| [[100 mm/56 B-34 (100 mm)|100 mm/56 B-34]] || HE || 100 || 900 || 15 || 21 || 17 || 1.95 || 24 || 24
|-
|[[File:Britain flag.png|link=|25x25px]]
| [[4 inch/45 Mark XVI (102 mm)|4 inch/45 Mark XVI]] || HE || 102 || 811 || 10 || 20 || 6 || 8.5 || 20 || 20 
|-
|[[File:Germany flag.png|link=|25x25px]]
| [[10.5 cm SK C/32 (105 mm)|10.5 cm SK C/32]] || HE || 105 || 875 || 15 || 6.8 || 6.8 || 1.55 || 20 || 20 
|-
|[[File:Japan flag.png|link=|25x25px]]
| [[100/65 mm Type 98 mod A (100 mm)|100/65 mm Type 98 mod A]] || HE || 100 || 950 || 15 || 12 || 16 || 0.95 || 13 || 13 
|-
|}

==== AP and SAP ====
{| class="wikitable sortable" style="text-align:center" width="100%"
|-
! colspan="2" rowspan="2" |Cannon
! rowspan="2" |Ammo
! rowspan="2" |Calibre<br>(mm)
! rowspan="2" |Muzzle Velocity<br>(m/s)
! rowspan="2" |Sustained rate of fire<br>(rounds/min)
! colspan="2" |Targeting speed<br>(°/s)
! rowspan="2" |TNT Equivalent<br>(kg)
! colspan="2" |Penetration<br>@ 0° Angle of Attack (mm)
! colspan="2" |Penetration<br>@ 60° Angle of Attack (mm)
|-
!Horizontal!!Vertical!!1,000 m!!5,000 m!!1,000 m!!5,000 m
|-
|[[File:Kingdom Italy flag.png|link=|25x25px]]
| '''100 mm/47 O.T.O. Mod. 1928''' || APHE || 100 || 850 || 9.6 || 11 || 6 || 0.82 || 129 || 67 || 52 || 29
|-
|[[File:Britain flag.png|link=|25x25px]]
| [[4 inch/45 Mark XVI (102 mm)|4 inch/45 Mark XVI]] || SAP || 102 || 811 || 10 || 20 || 6 || 0.6 || 102 || 64 || 43 || 27
|-
|}

== Usage in battles ==
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These guns are used exclusively as secondaries and unlike a number of other secondary guns on cruisers - they are best left for the AI to control at all times, as the guns simply lack both punching power and/or rate of fire to be worth being manually-controlled, maybe with exception of the [[Zara (Family)|Zara-class]] where three-turret broadside is just-about enough to save the day in specific circumstances. These guns should be primarily thought of as a psychological warfare against enemy airplanes: they offer just enough fire to look discouraging, while also being able to score a random hit every now and then. They are by no means reliable, but still better than having no long-range protection (an issue Japanese warships struggle with throughout the research tree).

=== Pros and cons ===
<!-- ''Summarise and briefly evaluate the weaponry in terms of its characteristics and combat effectiveness. Mark pros and cons as a list.'' -->

'''Pros:'''

* Good APHE shell for the calibre
* Long engagement range

'''Cons:'''

* Poor damage potential (small explosive fillers in HE shells, low rate of fire, poor muzzle velocity)
* Lack of HE-VT shells
* Low targeting speed

== History ==
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The Austro-Hungarian Empire began to lay down plans for a much expanded naval force in the early 1900s. No longer content with a coastal defense force, they wanted to have control over the Adriatic Sea. The change was influenced by the politics of Marinekommandant (Chief of the Navy) Rudolf Montecuccoli and crown prince Archduke Franz Ferdinand who viewed Italy as a threat, along with the new railway linking their ports at Trieste (present-day Italy) and the Dalmatian coastline (present-day Croatia) to the rest of the Empire. The new fleet expansion program led to orders for a new cannon to arm their destroyers and scout cruisers leading to the Škoda K 10 first developed in 1907 and adopted in 1910. After World War I ended, the Austro-Hungarian Empire was dismantled by the Allied Powers. This dismantling included the navy with Italy getting the K 10 guns on the ''Brindisi'' and ''Venezia'' which were ships ceded from the Austro-Hungarian Navy as war reparations.

The Italians were so enamoured with the design, they began to produce the design locally through OTO which resulted in a variety of different variants of the design. The O.T.O. Mod.1928 was a dual-mount anti-aircraft variant with electrically powered adjustable trunnions, rope rammers and mechanized spring, and a loose liner. Despite being intended for anti-aircraft use, the gun was too slow for this role, particularly if a ship was rolling and it was instead more suited for barrage fire. The RN ''Balzano'', [[Condottieri (Family)|''Condottieri''-class]], RN ''San Giorgio'', and [[Zara (Family)|''Zara''-class]] cruisers all used these guns. They were also used on the ''Conte di Cavour''-class dreadnoughts. The Soviet Navy also used this gun as the [[Minizini (100 mm)|Minizini]] named for the developer of the duel mount Italian Commandante Minizini.

== Media ==
''Excellent additions to the article would be video guides, screenshots from the game, and photos.''

== See also ==
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* ''reference to the article about the variant of the cannon/machine gun;''
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* [[Minizini (100 mm)]] - Soviet variant.
* [[100 mm/47 O.T.O. Mod. 1937 (100 mm)]] - later single-mount variant.

== External links ==
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* ''topic on the official game forum;''
* ''other literature.'' -->

* [[wikipedia:Škoda 10 cm K10|[Wikipedia] Škoda 10 cm K10]]
* [http://www.navweaps.com/Weapons/WNIT_39-47_m1924.php <nowiki>[NavWeaps]</nowiki> Italy 100 mm/47 (3.9") Models 1924, 1927 and 1928]

{{Italy naval cannons}}

[[Category:Naval cannons]]