Mortar mobility: Patria’s TREMOS takes aim at the modern battlespace

This In Conversation interview is brought to you by Shephard in partnership with Patria.

The Ukraine war has demonstrated the complex modern demands on mortar systems, which must now combine rapid firepower and accuracy with high mobility. This evolving landscape was key to the development of TREMOS, the new mobile mortar system from Patria, according to Lauri Pauniaho, the company’s Director, Weapon Systems.

Russia’s invasion of Ukraine has been a wake-up call for the European defence sector, Pauniaho said, prompting a general move towards rearmament. This has brought about rapid evolution in a number of areas, he noted, with mortars being a key example.

‘In Ukraine, mortars have once again shown their performance,’ he said. ‘This has contributed to new inventions, such as Patria’s TREMOS.’

The company unveiled TREMOS at the Future Mortar Systems conference in London in October. The new system is designed to be a cost-effective solution for militaries looking to modernise their traditional mortar inventories.

Developed in close collaboration with the Finnish Defence Forces (FDF), it features advanced recoil technology, enabling it to be integrated into a wide range of vehicle types. Importantly, this eliminates the need for ground support when firing, allowing for quick displacement and boosting the ‘shoot-and-scoot’ capability of the system.

Ease of integration

TREMOS features an integration module and connecting interface that makes it fast and simple to move a mortar from one vehicle to another, whether a 4x4, 6x6, 8x8 or light tracked platform.

It can open fire within 60 seconds of arriving at its chosen position and receiving its mission instructions, leaving immediately after firing the last round.

TREMOS is compatible with all qualified 120mm and 81mm smoothbore mortar barrels and ammunition, and can be used as a standalone system or as part of a larger mobile firing unit. Additionally, it has a modular configuration to optimise available space; this also makes it quicker and easier to integrate the system and transfer it from one vehicle to another.

The development of this highly mobile solution reflects the changing demand for mortar systems on the battlefield, noted Pauniaho. As the counter-battery threat has evolved – particularly from peer rivals – so mobility has become more crucial than ever.

It can take about three minutes for counter-battery fire to hit the mortar’s position, said Pauniaho. If you spend one minute exercising the firing mission, that allows about two minutes to get out, he noted, emphasising the importance of the ‘scoot’ element.

‘The mobility factor with Patria TREMOS is the key. With this type of system there is not much you can do to protect yourself against counter-battery fire other than extract yourself from the firing position as quickly as possible,’ he said.

With TREMOS, there is no need to deploy the mortar on the ground, making it a highly mobile and quick solution, its key advantages. ‘The secret is in the recoiling system: we reduce the force to such a level that a vehicle can withstand it without ground support,’ Pauniaho said, noting that this provides increased mobility and therefore survivability.

Additionally, TREMOS offers the ability to target the entire battlespace, unlike a ground-based or hinged weapon.

‘They have a limited firing sector. Some ground-supported and hinged systems are not allowed to fire 360 degrees because of restrictions caused by the weapon system design, but we don't have those restrictions. Patria TREMOS has full 360-degree traverse allowing for rapid aiming without any need to manoeuvre the vehicle to correct position.'

Complementary offering

TREMOS is designed to complement – not replace – NEMO, Patria’s 120mm turreted, remote-controlled mortar system that offers armoured hull protection against ballistic, mine, IED and other threats. NEMO has higher levels of ballistic protection due to the unique demands associated with the system.

‘Our NEMO turreted mortar is playing on a different field, so I don’t see any problem with a country acquiring NEMO for certain purposes and TREMOS for others,’ stressed Pauniaho.

TREMOS is a key expansion of Patria’s mortar portfolio, he added. With NEMO, ‘we have the best turreted mortar for the most demanding threat scenario and the highest level of mobility. Now we are providing a novel solution to markets between the ground-mounted, towed mortars and hinged/floor-mounted mortars, combining the low cost of towed with the high mobility of floor-mounted systems.’

While TREMOS aims to meet a growing need for a highly mobile solution, it can also receive additional ballistic protection as needed, should the vehicle have the option to support this, for example high side plates or a roof over the ammunition storage. Additionally, it can be used as a floor-mounted system if customers want that, Pauniaho added.

Finnish needs

Patria developed TREMOS in close collaboration with the FDF, which possesses several hundred 120mm mortars. ‘The FDF saw that mobility is the key element,’ Pauniaho explains. ‘They also did not want to have a fixed integration approach but needed a weapon that could be easily changed from one platform to another. That is why there is no electric, hydraulic, pneumatic or other connection to the vehicle.'

In the case of a hinged or floor-mounted system, explained Pauniaho, the mortar is bolted to the chassis or floor of the vehicle and operated from there. The FDF required a new system that could be removed and replaced more easily.

‘They thought that if there is an engine failure, for example, or a flat tyre or another problem, they want to be able to take the weapon out of the vehicle and quickly put it into another platform,’ he explained. ‘That was a key factor.’

Patria’s work with the FDF began with a detailed discussion of the military’s ideas for future demands in mortar systems. ‘We looked at the market and there was no system available to fulfil all their needs,’ Pauniaho explained.

The company therefore decided to utilise its own expertise, developing a prototype in less than 12 months. It conducted test firings to verify the operational safety of the TREMOS system, with these featuring various vehicle platforms and using the FDF’s Tampella type 120 Krh/92 and 81 Krh/71 mortars.

The FDF subsequently tested the system widely, with Patria using feedback from those trials to inform work on the pre-series phase of TREMOS development, Pauniaho said.

Patria TREMOS can be quickly readied for new customers. Integration design onto a new vehicle type should take no longer than three to six months, with a similar period of time to integrate a new barrel, Pauniaho said. With perhaps two to three months of testing, this means the entire process should take about a year, although this depends on the vehicle in question and the level of cooperation with its manufacturer.

After the integration module has been designed and tested, the customer can then easily transfer the weapon between platforms, Pauniaho explained. ‘That was one of the key requirements from the FDF,’ he emphasised, with the ability to utilise a forklift, crane or hook-lift approach.

Future focus

In the short to medium term, Pauniaho expects to see greater versatility within the mortar systems market. For example, he said hinged mortars may need to come down in price and offer reduced complexity to become more desirable and cost-effective. For Pauniaho, TREMOS has ‘started a bit of a revolution in the field of mortars’, offering the prospect of heightened mobility even for ‘low-end’ solutions.

‘Since TREMOS can also be used as a floor-mounted type installed in open-roof vehicles, the current competition there might also need to evolve,’ he noted.

In the longer term, Pauniaho will be closely watching the evolution of mortar ammunition. ‘The ammunition can be a carrier for multitude of effectors,’ he said. ‘I’m keen to see what manufacturers might bring to the table in the future.’

Patria is ready to discuss the potential use and applications of TREMOS with other interested customers, Pauniaho said. As the battlespace evolves in the future, the company will seek to embrace shifting demands in mortar needs, combining mobility with firepower and protection.

‘We welcome all customers to come and discuss their needs with us and whether Patria TREMOS can fulfil them,’ he said. ‘In terms of markets, we are keen to work with all countries that request a solution for an affordable and quick acquisition to field large quantities of mortar systems.’