October 2004
 

MONARC 155 mm naval gun

Following successful tests, sea trials now planned

Since August 2004, the MONARC project group, made up of the defence contractors Krauss-Maffei Wegmann GmbH, Howaldtswerke Deutsche Werft AG and Rheinmetall Waffe Munition GmbH, has been engaged in an in-depth study involving preparations for the F125-class frigate design phase, aimed at creating a "naval gun fire support" capability.

MONARC, which stands for Modular Naval Artillery Concept (for naval gun fire), is a solution based on 155 mm technology already fielded by the German Army Artillery Corps, and which is in production for various european countries. Compared with existing systems, MONARC offers naval surface combatants a means of substantially improving the range and effectiveness of shipboard artillery, as well as making new types of ammunition available for naval operations. Furthermore, it provides navies with an opportunity to take advantage of the technological lead enjoyed by the German defence industry in the domain of large calibre artillery systems for land warfare applications.

Instead of developing a new system from scratch, it will be possible to turn to a tried-and-tested weapon system representing the cutting edge of ground forces artillery technology. The MONARC concept, developed with HDW acting as lead company, entails integrating the turret and main armament of the PzH 2000 self-propelled howitzer onto the deck of a ship by means of an elastic mounting.

Following preliminary work, the turret of a PzH 2000 was mounted on the foredeck of the new F124-class frigate 'Hamburg' in December 2002 in order to carry out a demonstration of the new concept. The objective of the successful presentation was to show the fundamental feasibility of a connection of this type. As a result of the demonstration, it was shown that an adaptation to the infrastructure of new and existing ships is possible at reasonable cost, while still maintaining the essential performance characteristics of the PzH 2000.

The special naval engineering challenges involved in integrating the turret of the PzH 2000 onto ships hinge on the need to place large calibre ordnance on a relatively small vessel. Here, the weight of the gun turret of the PzH 2000 poses no problems, since it barely weighs more than the medium calibre gun turrets currently in service; nor does the space required above and below decks, which equates to that of a conventional 76 mm gun. On the other hand, the effects of the gun's recoil forces on the structure of the ship during and after firing require particular attention. The transmission of forces to the structure of the ship is to be modified by means of an elastic mounting system.

In a further step, a series of tests were thus carried out at the Erprobungszentrum Unterluess, Rheinmetall Waffe Munition's testing centre in Unterluess, Germany, for gathering data on the dynamic forces affecting the platform structure during firing.

In order to this, an elastic mounting consisting of 16 special shock absorber elements was assembled on a specially designed firing pedestal together with the turret of a PzH 2000, comparable with the system used to mount the turret on the deck of a ship. The objective was – during live fire – to determine the maximum stress limit using different barrel elevations, projectile types and propelling charge volumes, aided by a battery of measuring equipment, including extensometers, force measuring systems, high-speed cameras, etc. The stress values were subsequently entered into a finite element model of a frigate in order to calculate the impact on the structure of the ship. A key finding of this simulation was that the structure of the frigate investigated was capable of withstanding the not inconsiderable stresses associated with firing. As a next step, the MONARC project group plans to validate the results of this structural simulation during firing trials at sea.

Moreover, the project group also intends to investigate additional parameters for integrating the turret of the PzH 2000 in future naval vessels. Here, the focus will be on fully automatic shipboard ammunition feeding.

Particularly in the United States, elaborate development efforts are underway on behalf of the US Navy to improve the range and effectiveness of future naval artillery and ammunition, giving it an enhanced capability of engaging targets on land. These development efforts are expensive and time consuming.

This is where the MONARC project group initiative comes in: a solution requiring relatively little development effort which can be realised quickly and at reasonable cost, involving the shipboard integration of a state-of-the-art, large calibre gun, capable of firing a wide variety of ammunition types and engaging targets (including on land) at extensive ranges – and available immediately.

The PzH 2000 gun turret meets these requirements. The PzH 2000 self-propelled howitzer is the world's most advanced 155 mm / 52cal tube artillery system. By the end of 2002, general contractor Krauss-Maffei Wegmann had supplied a total of 185 systems to the German Army. Rheinmetall Waffe Munition is responsible for the system's main armament and ammunition. With orders already in hand from Greece, the Netherlands and Italy, the PzH 2000 is well on its way to become the standard Nato artillery system of the future.

The PzH 2000 is characterised by fully autonomous navigation and fire control technology as well as fully automatic shell handling. Moreover, it features a rate of fire of ten rounds per minute and, thanks to its high-precision gun laying system, achieves a high degree of accuracy. A new generation of artillery ammunition currently being developed by Rheinmetall Waffe Munition engineers promises to bring targets over 80 kilometres away to within range.

Since the gun turret is autonomous, the requirements on the shipboard power supply are limited to a 24-volt power hook-up and a secure link to the operations centre and bridge. In addition, the ammunition storage and handling infrastructure has to be modified. Furthermore, in order to compensate for the movement of the ship, the gun laying system has to be stabilised.

MONARC thus represents a forward-looking solution for mounting a high-performance gun on frigate-sized ships, whose advantages are by no means limited to extensive range and extreme lethality. Thanks to the wide variety of ammunition types available, naval units will have at their disposal new capabilities for ship-to-ship engagements as well as for providing close fire support of own troops in coastal areas and executing other fire missions. Moreover, navies stand to benefit from substantial synergy effects in terms of training and logistics, since existing ground forces infrastructure can be jointly used. And, as shipbuilders Howaldtswerke Deutsche Werft point out, the system's modularity facilitates the adaptation and retrofitting of existing ships.
 

This article originally appeared in the September 2004 issue of Naval Forces.