Tlatlamani-class frigate

ACZ Molotecatl
Class overview
Name:	Tlatlamani-class frigate
Builders:	Acalliquetzcan Ecatzacuili
Operators:	Zacapine Navy
Cost:	Undisclosed
In service:	1968-Present
Planned:	51
Completed:	48
Cancelled:	3
Active:	34
General characteristics
Class and type:	Anti-submarine frigate
Displacement:	3,600 tonnes
Length:	124.5 meters
Beam:	13.0 meters
Draft:	7.3 meters
Propulsion:	Single-shaft CODAG ∟2x Oyetzec T21 diesel engines ∟ 1x Tlahqia CL10 gas turbine engine
Speed:	28 knots maximum speed 15 knots cruising speed
Range:	5,000 nautical miles (maximum range traveling at cruising speed)
Complement:	153
Sensors and processing systems:	• OTTla Air Scan Radar • Hueca YI2 Navigation Radar • 2x O6Y Tletechiuh Fire Control Radar • A8OT ayutonacaz (retractable sonar) • A19YCT ayutonacaz (bow sonar) • A2M6 ayutonacaz (towed sonar)
Armament:	1x Tozan-Y 12-cell short-range SAM launcher with capacity for 24 reloads 1x twin TC-120 120mm canon 2x TCM-30 6-barrel 30mm rotary canon 2x ITTA anti-submarine rocket launcher 2x Minacachalli two-tube anti-submarine missile launcher 2x triple 533mm "Xoc" torpedo launcher
Aircraft carried:	2x Itz-41 naval synchropter
Aviation facilities:	1x aft aircraft hangar

The Tlatlamani-class frigates are a series of anti-submarine warships built for the Zacapine Navy to address one of the principal vulnerabilities of the surface fleet and the merchant marine. The Tlatlamani frigates are the Zacapine Navy's premier anti-submarine vessel, produced in large numbers in order to maximize the number of anti-submarine platforms available for the Navy's needs. Because of the needs to produce the ships in large numbers, the Tlatlamani class was designed to be as cheap to built and operate as possible while maintaining effectiveness in detecting and destroying submarines, resulting in a highly specialized vessel with little versatility outside the role of anti-submarine warfare. Although armed with limited air defenses and naval guns to allow a Tlatlamani frigate to defend itself away from the fleet, the frigates are armed and equipped almost exclusively for engaging submarines, and are generally intended to operate in close coordination with other vessels that can protect them from the threat of enemy missiles, aircraft and surface combatants.

Development

The need to develop a reliable means to counter the threat posed by submarines was first brought to the attention of the Zacapine Admiralty during the Hanaki War, which was the first trans-oceanic naval engagement the newly minted Zacapine Navy had faced since the revolution. During the war, the combined power of the Onekawan Navy and the Zacapine First Air Fleet proved more than a match for the surface fleets of the opposing Ozerosi states, but had great difficulty in containing the advance of early submarines which preyed on the exposed Zacapine supply lines stretching across the Vespanian and Makrian oceans. It was understood that in virtually any future conflict in Malaio in which the Zacapine Navy would become involved, the enemy would almost certainly seek to similarly disrupt the transit of Zacapine supply ships from Oxidentale, vital to the war effort. This vulnerability would be made all the more pressing by the immense distances involved, with Zacapine supply ships and Naval squadrons regularly transiting every major ocean in the world except the Salacian. From the Hanaki War up until the late 1950s, the Zacapine Navy relied on naval aviation for anti-submarine duties, deploying a large number of small aircraft carriers to accompany its flotillas and supply convoys which could deploy aircraft to spot and destroy submarines with air-launched torpedoes.

The outbreak of the Third Uhlangan Civil War in 1963 prompted a series of military and naval reforms and refits, including the transition of the Zacapine Navy into a nuclear-powered force to be built around aircraft carriers with nuclear propulsion, which would be much larger than the light carriers the Navy had previously employed. The new carrier project would greatly expand the Zacapine Navy's capacity for sustaining naval air operations in a conflict zone, although the development would not be completed in time for the new class of nuclear-powered fleet carriers to see service during the Uhlangan War. However, it would also concentrate the Navy's air power in just a handful of carriers, which could not be everywhere the Navy needed anti-submarine capability at once. Among the many new projects being set in motion by the tremendous naval refit of the 1960s and 70s was the initiative under designer Inic Atlacatl and the Acalliquetzcan Ecatzacuili shipyard to develop a new anti-submarine vessel that could be produced in large numbers to deploy all across the Zacapine Navy's areas of concern.

Atlacatl's proposal, designated Plan 26 by the shipyard, was for a relatively compact and specialized anti-submarine frigate. In order to the reduce the cost of the platform, Atlacatl proposed equipping a small ship with as much anti-submarine equipment as it could carry and little else, in order to create a vessel with as much combat effectiveness against submarines as possible at a low cost. Atlacatl would later admit in an interview in 1988 that he drew heavy inspiration in his design from another naval designer, who had similarly submitted a plan for an even smaller and more specialized craft the size of a cutter. The key innovation in Plan 26 was the addition of anti-submarine missiles and rockets beyond the torpedo launchers the smaller versions of the concept had called for, in order to make the vessel capable of engaging submarines at greater ranges and in a variety of potential engagement scenarios. The Navy took interest in Plan 26, but required that Atlacatl redesign the concept to include anti-air and anti-ship capacities for self-defense, which he had initially omitted to reduce costs. The prototype produced at Acalliquetzcan Ecatzacuili was put through sea trials in 1967 and accepted, with full production and entry into service beginning in early 1968.

General characteristics

The main weapons of the Tlatlamani class are suited for engaging submerged targets under various conditions. The first element of the anti-submarine arsenal aboard the frigate are two Minacachalli-type missile launchers each with two missile tubes, allowing the vessel to load and fire up to four TlA-7 Pilotihuetzi anti-submarine missiles. The Pilotihuetzi missile system, a modification of an older generation of Zacapine anti-ship cruise missiles, is capable of engaging submerged targets at a range of as far as 80 kilometers by deploying a torpedo or depth-charge warhead over the target from above. The frigate is also capable of directly launching torpedoes with its two sets of three 533mm torpedo launchers. The effective range of the torpedoes varies from 10-45 kilometers depending on the variant being loaded. More advanced 533mm torpedoes are equipped with sonar systems and wake homing sensors to independently seek their targets, allowing the ship to engage multiple targets at once with torpedoes. At closer ranges, the Tlatlamani can employ its two ITTA anti-submarine rocket launchers, which fire unguided rocket-propelled depth charges with an effective range of 5,500 meters and effective depth of 500 meters.

In order to detect submarines, the Tlatlamani class is equipped with three types of sonar (Ayutonacaz, lit. "wet ears") sensor systems. The ship has two sonar domes in the hull, one fixed in place at the bow of the vessel and the other installed in a retractable configuration amidships. A towed sonar sensor is deployed from the aft to better isolate it from any interference coming from within the ship itself. In addition, the Tlatlamani class has an aft helicopter pad as is common for naval vessels of its sized and role, from which the ship's compliment of two Itz-41 synchropters can be deployed. Each Itz-41 also carries its own dipping sonar as well as sonobuoys that can be deployed to aid in submarine detection. When a target is spotted, the synchropters can report its position for the Tlatlamani to engage it with its onboard weapons, or it can engage the target directly by deploying depth charges through its rear clamshell doors.

The Tlatlamani frigates are armed against targets other than submarines because of the designers unwillingness to leave the frigates effectively defenseless against other threats, even though these added weapons would add to the unit cost of the vessel without improving its effectiveness in its specialist role. Most important of these is the Tlatlamani's SAM battery, a Tozan-type modernized short-range launcher with 12 missile cells. The Tozan SAMs are primarily intended to be use against attacking aircrafts but may also be used as an anti-missile defense system, although their effectiveness in this role has not been proven in real combat to date. Against the threat of missiles, the Tlatlamani is also armed with two 6-barrel 30mm rotary canons connected to the ship-board fire control system, which are capable of acting as CIWS point defense weapons to destroy incoming missiles in the moments before they strike the ship. In order to arm the vessel against enemy surface combatants and -in theory- ground targets, the Tlatlamani's designers also included a twin TC-120 12cm gun turret near the bow of the ship.