Plan 1781 intelligence ship

Side view of TJG-772 in 2016.
Class overview
Builders:	Haeju Menghwa Shipyard
Operators:	Menghe
Preceded by:	Plan 1933 intelligence ship
Built:	2011-2019
In commission:	2016-present
Planned:	4
Completed:	4
Active:	4
General characteristics (as built)
Type:	Intelligenge ship
Displacement:	5,150 tons full
Length:	112.9 m overall 103.5 m at waterline
Beam:	16.3 m
Draught:	5.64 m (full load)
Propulsion:	2 × 6,600kw diesel engine 2 shafts
Speed:	24 knots
Range:	12,000 nmi (22,000 km) at 14 knots
Complement:	38 officers 66 enlisted crew up to 26 additional agents
Sensors and processing systems:	2 × unknown large radome 1 × high-frequency anti-saboteur sonar
Armament:	1 × HP-35/2 Type 110 twin 35mm anti-air gun 2 × 12.7mm GCh-75 HMG
Aircraft carried:	1 × GH-26 utility helicopter
Aviation facilities:	Flight deck and hangar

Plan 1781 is the design designation given to a group of four spy ships produced in Menghe during the 2010s. They are designed to conduct SIGINT, ELINT, and MASINT missions on behalf of the Menghean Navy and External Intelligence Agency at long distances from Menghe's home waters. These vessels are also capable of serving as missile range instrumentation ships, though that is not their primary purpose.

Design and development

Prior to the 2010s, the Menghean Navy had two dedicated spy ships in service: the Plan 1933 class, built in the 1970s and commissioned in 1981 and 1983.

The Plan 1781 class intelligence ships were ordered as part of a broader Navy initiative to increase Menghe's blue-water capabilities. Unlike previous intelligence-gathering ships, which mostly operated in the South and East Menghe Seas, these new ships were designed to monitor naval exercises around the Casaterran subcontinent, stopping at bases in Kolodoria and Idacua to take on fuel and supplies. As such, they were built with a much greater range and endurance than their predecessors, or for that matter many other spy ships. This includes CONREP stations for accepting fuel and moving supplies from underway replenishment ships.

In addition to an array of radio antennas in the HF, VHF, and UHF range, the Plan 1781 ships are fitted with the HR-280 long-range surface search radar, two large domes covering powerful missile and aircraft tracking radar dishes, and a hangar for a GH-28M utility helicopter, which is typically fitted with SIGINT or ELINT pods on its pylons. A radar-aimed twin 35mm turret forward and two stabilized, remotely-aimed 12.7mm HMGs aft provide a measure of defense against helicopters and small boats, though without a dedicated air search radar, these ships have only a limited ability to protect themselves against fast jets and missiles.

Operational service

In May 2017, Sieuxerrian pilots photographed TJG-772 in international waters off the coast of Sylva, the furthest afield a Menghean intelligence ship had ever been spotted. TJG-772 subsequently cruised along the southwestern coast of Casaterra and loitered off the coast of Anglia and Lechernt before heading to a port in Kolodoria.

During the 2021 crisis in Kawazi, the Entente Cordiale surged two carrier battle groups through the Strait of Portcullia as a show of force and to deter Menghean involvement. TJG-774, previously docked in Quang Pha, sortied to intercept them as they passed through the strait, and trailed them from a distance throughout the surge operation.

At the start of the Second Pan-Septentrion War, TJG-772 (painted with the hull number 773) was operating off the coast of Casaterra. One week prior to the commencement of hostilities, she shut off her AIS beacon and relocated to a new position closer to Sylva, where she attempted to monitor radio traffic in the opening hours of the war to assess damage from Menghe's opening submarine strike and assess the speed of the EC's naval reaction.

After Calafia attacked Uskonmaa toward the end of 2022, the Menghean Navy relocated TJG-775 from its patrol area near Southwest Casaterra to a new patrol area in international waters off Calafia. There, she collected independent data on air and naval combat in the area of hostilities. At one point during this mission, a single unarmed Sebrenskiyan F-35 approached the ship, passing over it at an altitude of 800 meters; electro-optical sensors aboard TJG-775 were able to track the fighter, and it is highly likely that the ship used its large tracking antennas to acquire data about the F-35's radar cross section at various angles during the overflight.

Ships in the class

Unusually for the Menghean Navy, ships in the Plan 1781 class are not given names, only hull numbers. A Sieuxerrian analysis of Menghean AGI deployments in 2021 also found evidence that on at least some occasions, the Menghean Navy repainted the hull numbers of individual Plan 1781 ships to disguise them as their sister ships.

Hull number	Launched	Commissioned
TJG-772	2013-09-23	2016-03-15
TJG-773	2014-06-04	2017-01-16
TJG-774	2016-01-06	2018-07-02
TJG-775	2016-12-14	2019-03-11

Successor class

The Menghean Navy is rumored to be working on a successor class to the Plan 1781 intelligence ships, with greater endurance and more advanced sensors. As of 2022, no ships in this class have been launched, and intelligence remains sparse.