The ASELSAN STOP system is a remotely operated and stabilized 25 mm naval gun system developed to address the growing threat of asymmetric warfare in maritime environments. It is optimized to engage small, fast-moving surface targets such as armed speedboats, unmanned surface vessels, piracy threats, and potential sabotage attempts in littoral and harbor environments.

Operational Purpose and Role

STOP serves as a close-range naval defense layer. Positioned between heavy main guns and light machine gun systems, it fills a critical operational gap. The 25 mm caliber provides sufficient firepower to neutralize lightly armored or fast attack craft while maintaining controlled engagement capability in congested maritime environments.

Additionally, the system can provide limited capability against low-altitude and slow-moving aerial threats, including certain types of unmanned aerial vehicles, depending on engagement conditions.

Doctrine and Concept of Employment

The system is typically deployed in:

• Harbor and naval base protection
• Maritime patrol and interdiction missions
• Anti-piracy and anti-smuggling operations
• Amphibious operation force protection
• Swarm attack defense scenarios

STOP can automatically slew to target coordinates received from the ship’s radar or combat management system, significantly reducing reaction time between detection and engagement.

System Architecture

The STOP system consists of three primary subsystems:

Stabilized Gun Turret

• Dual-axis stabilization
• Integration of a 25 mm automatic cannon
• Precision servo control system

Electro-Optical Sensor Suite

• Daylight TV camera
• Thermal imaging camera
• Laser rangefinder
• Automatic target tracking algorithms

Weapon Control Unit

• Operator console
• Advanced graphical user interface
• Manual and automatic operating modes
• Combat Management System integration

The modular architecture allows flexible integration into various naval platforms and supports network-centric warfare concepts.

Survivability and Protection

As a remotely operated system, STOP eliminates the need for exposed deck gunners, significantly improving crew survivability. The stabilized turret maintains accuracy under high sea states and vessel maneuvering conditions.

Detailed ballistic protection levels of the turret are not fully disclosed in publicly available sources.

Accuracy and Reaction Time

Thanks to dual-axis stabilization and automatic ballistic computation, the system can engage moving targets from a moving platform with high precision. The fire control system calculates lead angle, target speed, platform motion, wind, and ammunition characteristics.

Exact reaction time values are not publicly disclosed.

Integrated Ecosystem

STOP integrates with:

• Shipborne radar systems
• Combat Management Systems (CMS)
• Navigation systems
• External sensor networks

It can automatically cue to designated targets provided by other onboard sensors.

Advantages and Limitations Against Modern Threats

Advantages:

• Effective against asymmetric surface threats
• Stabilized engagement capability in rough seas
• Remote operation enhances crew safety
• Modular sensor and fire control architecture

Limitations:

• 25 mm caliber limits effectiveness against heavily armored vessels
• Not a dedicated close-in air defense (CIWS) radar-guided system
• Engagement range is shorter compared to missile-based systems

Variants and Configurations

The STOP family includes configurable sensor packages and integration options tailored to customer requirements. Public sources do not detail specific block versions or modernization roadmaps.

Operational Use and Inventory

The system is deployed within the Turkish Naval Forces and Coast Guard platforms. Export customers are reported in open sources; however, comprehensive official user lists are not fully disclosed.

Detailed Technical Specifications

Weapon System

• Caliber: 25 mm
• Cannon Type: 25 mm KBA automatic cannon
• Ammunition: 25x137 mm NATO standard
• Rate of fire: Dependent on KBA configuration
• Effective range: Several kilometers depending on ammunition type (exact operational engagement envelope not publicly specified)

Stabilization

• Dual-axis stabilized turret
• High-precision servo control
• Capable of firing accurately while underway

Sensors and Detection Capability

• Daylight TV camera
• Thermal imager
• Laser rangefinder
• Automatic target tracking
• Simultaneous display of TV and thermal imagery

The system does not include an organic search radar but can receive cueing from shipboard radar systems.

Engagement and Fire Control

• Automatic ballistic calculation
• Manual and semi-automatic modes
• Automatic target tracking
• Automatic slewing to designated coordinates

Command and Control

• Integration with Combat Management Systems
• External sensor data input capability
• Remote operator console

Installation and Platform Integration

• Deck-mounted naval installation
• Modular design
• Installation time varies by platform configuration
• Designed for harsh maritime environments

Personnel and Operation

• Operated from inside the vessel
• Number of required operators not publicly specified

Frequently Asked Questions

What is the STOP system used for?

• STOP is designed to protect naval vessels against asymmetric surface threats such as fast attack boats, unmanned surface vehicles, and piracy-related threats. It provides stabilized, accurate firepower in close-range maritime engagements.

What is the engagement range?

• The effective range depends on the 25x137 mm ammunition type and engagement conditions. Public sources indicate a range of several kilometers, though exact operational limits are not disclosed.

What types of targets can it engage?

• Fast attack craft
• Light surface vessels
• Low-altitude, slow-moving aerial threats
• Unmanned surface platforms

Does STOP have radar?

• STOP does not include an organic radar. It relies on electro-optical sensors and can receive target data from shipborne radar systems.

How many targets can it engage simultaneously?

• The system is designed to engage one target at a time. Automatic target tracking is available, but multi-target simultaneous engagement capability is not publicly specified.

Is it mobile or fixed?

• It is permanently mounted on naval vessels but is considered mobile as part of the host platform.

Which platforms can integrate STOP?

• Patrol boats
• Fast attack craft
• Landing ships
• Coast guard vessels
• Auxiliary naval platforms

What are its equivalents?

• Comparable systems include other 25–30 mm stabilized naval remote weapon stations. STOP’s key differentiator is its domestically developed fire control and electro-optical architecture integrated by ASELSAN.

Sources

• ASELSAN official product brochures and website
• ASELSAN corporate publications and exhibition materials
• Open-source defense industry analysis platforms