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7 May 2025

Naval ballistic protection – challenges and solutions

Modern naval units are increasingly confronted with asymmetric threats. In addition to conventional attacks by enemy warships or aircraft, pirates, terrorists and non-state actors are playing an increasing role. Ships are particularly vulnerable to small-calibre fire, anti-tank weapons and attacks using explosives when operating near the coast, navigating canals, or in port.

In this blog post:

General challenges and requirements for naval protection systems
Threats to naval fleet formations
Specific features of protection systems for naval vessels
Vulnerability analyses to identify critical vulnerabilities
Summary

General challenges and requirements for naval protection systems

The key challenge in protecting naval vessels is to strike the right balance between protection, weight and corrosion resistance. Although STANAG 4569 was developed for land vehicles as a standard for ballistic protection testing, no universal protection class system exists specifically for the maritime sector. Consequently, the sector generally relies on the existing STANAG 4569 standards.

Levels	KE-Threats	Reference Artillery Threat
1	Weapon: Assault rifles: 7.62 and 5.56 mm Ammunition: Ball Distance: 30 m Angle: azimuth 360°; elevation 0-30°	Artillery 155 mm Estimated range of burst: 100 m Azimuth 360° Elevation: 0° -18°
2	Weapon: Assault rifles, 7.62 mm Ammunition: AP steel core Distance: 30 m Angle: azimuth 360°; elevation 0-30°	Artillery 155 mm Estimated range of burst: 80 m Azimuth 360° Elevation: 0° – 22°
3	Weapon: Heavy Machine Gun, 14.5 mm Ammunition: AP Distance: 200 m Angle: azimuth 360°; elevation 0°	Artillery 155 mm Estimated range of burst: 60 m Azimuth 360° Elevation: 0° – 30°
4	Weapon: Heavy Machine Gun, 14.5 mm Ammunition: AP Distance: 200 m Angle: azimuth 360°; elevation 0°	Artillery 155 mm Estimated range of burst: 25 m Azimuth 360° Elevation: 0 – 90°
5	Weapon: Automatie Cannon, 25 mm Ammunition: APDS and APFSDS Distance: 500 m Angle: frontal arc to centreline: ± 30° sides included; elevation 0°	Artillery 155 mm Estimated range of burst: 25 m Azimuth 360° Elevation: 0 – 90°
6	Weapon: Automatie Cannon, 30 mm Ammunition: APFSDS and AP Distance: 500 m Angle: frontal arc to centreline: ± 30° sides included; elevation 0	Artillery 155 mm Estimated range of burst: 10 m Azimuth 360° Elevation: 0 – 90°

You can find further information on STANAG 4569 in our blog post: STANAG 4569 Protection requirements for armoured military vehicles

In distant waters, the manoeuvrability of naval vessels is crucially important for responding flexibly and effectively to evolving threats and operational demands. A major factor in improving manoeuvrability is reducing the weight of vessels. Lighter vessels can accelerate faster, are easier to navigate and are more manoeuvrable overall, giving them a tactical advantage in complex deployment scenarios. In addition, weight savings contribute to fuel efficiency, allowing for an increased range and extended deployment period without having to replenish supplies. This is vital for operations far from domestic ports where supply lines are long and potentially at risk. Overall, a lighter design supports the interoperability and operational flexibility of naval vessels by improving their adaptability to different geographical and tactical conditions.

Threats to naval fleet formations

1. Ballistic threats from kinetic energy projectiles (KE threats)
Ships can be threatened by handguns, machine guns or large-calibre on-board cannons. The following pose particular threats:

Small-calibre weapons (5.56 mm – 7.62 mm) – when attacked by pirates or terrorists from speedboats.
Medium-calibre weapons (12.7 mm – 30 mm) – danger from rapid-fire cannons or ship-to-ship attacks.
Large-calibre guns (>30 mm) – mostly used in conventional conflicts by enemy naval units.

2. Shaped charges from anti-tank weapons such as RPGs
Shaped charge projectiles, such as RPGs (rocket-propelled grenades), which can cause devastating damage to unprotected areas such as bridge structures or ammunition stores, are particularly critical.

Threat of asymmetric attacks, such as pirates with RPGs approaching on speedboats.
Danger in narrow waters – for example, when crossing canals, in ports or in coastal areas with a high threat level.

3. Threat posed by micro-drones to naval fleets
Micro-drones pose a growing threat to naval fleet formations, as they are difficult to detect, inexpensive to procure and flexible to deploy. Their low radar signatures and flight altitudes make early detection challenging using traditional air defence systems. Small surface or underwater drones also pose a major threat if they are used against naval units in the harbour basin. Micro-drones can be equipped with weapons such as shaped charges and thus have a devastating effect on the target.

Asymmetric actors and states are increasingly relying on micro-drones to pose a significant threat to state-of-the-art warships with minimal effort. Naval forces should therefore invest in advanced anti-drone measures to address these emerging challenges.

Specific features of protection systems for naval vessels

1. Material selection: corrosion protection and lightweight construction
Protective materials for naval vessels must not only meet ballistic requirements, but also:

be corrosion-resistant, as sea water is highly corrosive to metallic materials.
be light, so as not to increase the ship’s weight and, in turn, compromise stability
be capable of being used in a modular form and flexibly adapted to the mission.

Image: Modular gun mount protection made of ceramic composite panels

Typical materials include ceramic composites, fibre composites or armoured steels with special corrosion protection coatings.

2. Protection of critical areas
Since the full armouring of a ship is impractical, protection focuses on particularly vulnerable areas:

Bridge and operating rooms to protect crew and control systems.
Ammunition storage areas to prevent secondary explosions from hits.
Engine rooms and propulsion sections to maintain manoeuvrability.

Image: Integration into the metallic structures of the bridge

Vulnerability analyses to identify critical vulnerabilities

Detailed vulnerability analyses are necessary to ensure the best possible protection. This involves:

1. Definition and analysis of threat scenarios, e.g. which weapons and types of attack are realistic?
2. Identification of weak points in the hull and superstructure, e.g. which areas need special protection?

3. Definition and testing of protective measures. The development of a protection concept includes the targeted selection of technologies and materials, followed by individual development, design optimisation and validation. Extensive evaluations test the effectiveness of the materials and protective systems.

Particularly problematic are hits that would cause a unit kill, i.e. knock the entire ship out of action, for example by:

A hit on the ammunition storage areas – risk of a chain reaction.
Damage to the bridge or operations centre – loss of control.
Destruction of the engine room – loss of manoeuvrability.

Redundant systems can be used to increase resilience. These systems protect supply lines, communication and navigation systems from secondary fragments and the effects of fire in the event of an overmatch scenario, thus significantly increasing survivability.

Summary

Protecting naval vessels against ballistic threats and RPGs presents unique challenges, as it must balance effective protection with lightweight, corrosion-resistant, and modular design. While STANAG 4569 specifies test methods for protective materials used in land vehicles, there are no standardised threat levels or protection classes explicitly defined for the maritime sector.

Targeted vulnerability analyses and the protection of critical areas such as the bridge, ammunition storage areas and engine rooms allow naval vessels to be effectively protected against asymmetric and conventional threats. However, ballistic protection is always a trade-off between weight, protection and operational flexibility, and poses a constant challenge for naval engineers and armaments experts.

Mehler Protection stands as the technology and market leader for naval protection systems in Europe. With its Multirole Armour Composite Components (M-RACC) system, Mehler Protection offers a modern, modular protection system with a low areal density, which is specially tailored to the requirements of maritime use scenarios. M-RACC systems provide reliable protection against ballistic projectiles and shrapnel as well as shaped charges and anti-tank weapons in maritime threat scenarios, tested in accordance with STANAG 4569 AEP-55, Vol. 1. The protection of critical areas of the ship, such as the bridge, operations centre, machine gun positions and ammunition storage areas, ensures the operational capability of the entire system and significantly increases the crew’s probability of survival. The individual protection solutions are designed by Mehler Protection on the basis of comprehensive threat analyses depending on the intended use and the resulting threat scenario. Based on decades of experience, Mehler Protection offers expertise as a system consultant for the design of naval protection systems and is therefore an important partner for leading shipyards in Europe and around the world.

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