RX-77AQ Guncannon Aqua – MechaBay

The RX-77AQ Guncannon Aqua was an amphibious mobile suit developed by the Earth Federation Forces as an underwater variant of the RX-77-2 Guncannon.

The “R” in the model code meant it was a Federation model¹ and the “X” indicated that it was an experimental mobile suit. The “77” in the model code denoted that it was developed from the RX-77 Guncannon line, and the “AQ” suffix stood for “Aqua”, indicating its amphibious capabilities.

History

The RX-77AQ Guncannon Aqua was developed by the Earth Federation Forces in the post-war period as part of their efforts to create amphibious mobile suits capable of underwater operations. The development was driven by the need for mobile suits that could operate effectively in marine environments, particularly in response to amphibious threats from Zeon remnant forces.

In August UC 0080, pilot Bianca Carlyle of the assault carrier Spartan engaged a Zeon remnant MSM-03 Gogg at Antarctica. The Guncannon Aqua was severely damaged during the battle, necessitating its disassembly to conduct repairs. This combat experience provided valuable data on the mobile suit’s performance in actual underwater combat conditions.

In the manga, the Guncannon Aqua was later deployed in a squadron with 3 RB-79[M] Ball Marine Types to capture the potential pilots for MS-06R Zaku II High Mobility Type (Reuse “P” Device) units at the Rig. During the chase of a Prober-class submarine carrying the pilots, it was hit by mines in Frizzy Yard, resulting in damages to its left arm and core area. It then surfaced due to a hull breach and was later found on a nearby flooded town.

After the Guncannon Aqua was repaired, it was retrofitted for land use and underwent training with the RX-78AL Atlas Gundam and 3 RX-79[GS] Gundam Ground Type S. After this training, the Guncannon Aqua was loaded on Landing Craft 3 (Orestes) and deployed at Taal volcano to stop the launch of additional Psycho Zaku units. During the final battle, Bianca attempted to join up with Io Fleming, but encountered the Living Dead Division’s engineers transporting a completed MS-06R-2P Zaku II High Mobility Type (Reuse “P” Device) Unit 2 to Daryl Lorenz. While Bianca ejected to safety, the Guncannon Aqua was lost when its reactor exploded after being damaged by an ambush from a Zaku Tank.

Design

The RX-77AQ Guncannon Aqua was an amphibious variant of the RX-77-2 Guncannon specifically designed for underwater combat operations. The most significant modification was the replacement of the original Guncannon’s thrusters with hydrojet thrusters mounted on the backpack, chest, and knees for underwater propulsion. These hydrojets allowed the mobile suit to manoeuvre effectively in aquatic environments while maintaining its artillery role.

The paint scheme was changed to blue to allow for better camouflage in underwater settings, departing from the traditional yellow and red colouration of the standard Guncannon. This blue colouration helped the mobile suit blend in with marine environments during underwater operations.

The mobile suit’s armaments were also modified for underwater combat effectiveness. The signature 240 mm cannons of the standard Guncannon were replaced with torpedo launchers, which were more effective underwater where conventional ballistic weapons would have severely reduced range and accuracy.

The standard cockpit configuration was retained in the torso, with appropriate sealing modifications to protect the pilot during underwater operations. The mobile suit maintained the basic frame and proportions of the original Guncannon while incorporating the necessary changes for amphibious operations.

Armaments

The Guncannon Aqua’s standard weapons were torpedo launchers for underwater ranged attacks and beam sabers for close combat. A specialised needle gun provided additional tactical options for underwater engagements.

Vulcan guns

Two vulcan guns were mounted in the head of the Guncannon Aqua, retained from the original Guncannon design. These rapid-fire weapons were used primarily against light-armoured support units and for point defence. In underwater environments, their effectiveness was limited due to water resistance, but they remained useful for surface operations and missile defence.

Beam sabers

The Guncannon Aqua carried 2 beam sabers, stored in recharge racks on the waist when not in use. These beam sabers were waterproofed for underwater close-quarters combat, allowing the mobile suit to engage in melee combat even in aquatic environments. The beam sabers used an I-field to contain Minovsky particles within the shape of a blade, and the particles broke down matter at a molecular level, allowing them to cut through almost any material.

The E-cap attached to each saber’s hilt recharged with Minovsky particles from the mobile suit’s reactor when stored in the recharge racks on the waist.

Torpedo launchers

The most significant armament change was the replacement of the standard Guncannon’s 240 mm cannons with 2 torpedo launchers mounted on the backpack over the shoulders. These launchers were specifically designed for underwater combat, where torpedoes were far more effective than conventional ballistic weapons. The torpedoes could engage both underwater and surface targets, maintaining the Guncannon’s role as a fire support unit in aquatic environments.

Needle gun

The Guncannon Aqua was equipped with a specialised needle gun as an optional handheld weapon. This weapon fired needles that could pierce through mobile suit armour fairly easily. In some configurations, the needles could be activated to spray a freezing agent to immobilise enemy suits, providing a unique tactical advantage in underwater combat situations.

Beam rifle

The mobile suit could also be equipped with a standard beam rifle for operations on land or when additional firepower was required. During the final battles of the Thunderbolt conflict, the Guncannon Aqua was provided with an assault rifle similar to the one used by the RX-78AL Atlas Gundam when it was modified for ground combat operations.

Known pilots

Bianca Carlyle

Behind the scenes

Yasuo Ohtagaki was the original mechanical designer for the Guncannon Aqua, as part of his work on the Mobile Suit Gundam Thunderbolt series. Ohtagaki noted in his design comments that “The original Gundam project started with the design of the Studio Nue power suit, and in that sense, the Guncannon is the ancestor of the Gundam, so perhaps that is why it is a more complete design.”

The Guncannon Aqua represents part of Ohtagaki’s broader exploration of amphibious mobile suit variants in the Thunderbolt universe, alongside the RB-79[M] Ball Marine Type and various Zeon marine types. The design philosophy emphasised practical modifications for underwater operations while maintaining the core identity of the original Guncannon.

Appearances

Mobile Suit Gundam Thunderbolt (manga)
Mobile Suit Gundam Thunderbolt (anime)

External links

RX-77AQ Guncannon Aqua (Thunderbolt anime) on MAHQ
RX-77AQ Guncannon Aqua on the Gundam Wiki

Federation in Japanese is renpou, hence the use of “R”. ↩