The now BAE Systems, Ground Systems Division M113 Armoured Personnel Carrier (APC) is still one of the most widely used vehicles of its type in the world.

When originally conceived well over 45 years ago, the main role of the M113 was to transport troops to as near their objective as possible, where the infantry would dismount and fight on foot.

Today, the M113 lacks armour, mobility and firepower to meet current and future user requirements. Against this background, Singapore Technologies Kinetics (STK) has developed, as a private venture, its own M113 upgrade, which is now being offered on the export market. This was shown for the first time at Asian Aerospace 2006 held in Singapore in February 2006.

The STK upgrade kit was conceived to enhance the current M113's performance and covers the key areas of mobility and firepower, as well as a number of survivability enhancements.

Design of the STK M113 upgrade is modular, enabling potential customers to select those parts that meet their specific operational requirements but at the same time having growth potential in the future.

This STK M113 upgrade is aimed at the export market but as of August 2007 this remained at the prototype stage.

The overall layout of the STK upgraded M113 is the same as the baseline BAE Systems, Ground Systems Division M113 series, which is covered in detail in a separate entry. The STK enhancements are mainly at the subsystem level.

In the STK upgrade, the existing M113 power pack consisting of a Detroit Diesel engine coupled to an Allison automatic transmission has been replaced by a new power pack, which has already undergone extensive trials in a M113 series vehicle prior to being installed in the latest STK M113 upgrade.

This new power pack consists of the Caterpillar 3126B 4-stroke six-cylinder turbocharged diesel engine developing 330 hp at 2,400 rpm, which meets EURO II requirements.

The diesel engine is coupled to an electronically controlled HMX-1100 hydromechanical continuously variable transmission. The new power pack also features a new exhaust system, two-stage air induction, compact cooling system and an upgraded driver's position, in which the conventional M113 series tillers have been replaced by a compact steering yoke.

The new power pack is also CAN Bus enabled and is equipped with a 260 amp alternator, making it ready for potential electrical/electronics installation and upgrades.

According to STK, this new power pack provides not only greater torque, speed and high-precision steering but also the ability to handle creep speeds without overheating.

The STK upgraded M113 achieves a maximum road speed of 75 km/h, cruising range of 480 km and a pivot turn through 360° in seven seconds. New improved severe duty final drives have also been installed.

The standard M113A1 APC has a gross vehicle weight of just over 11 tonnes but by installing heavy duty torsion bars the maximum gross vehicle weight of the M113 can be increased to 16 tonnes.

The standard M113 series APC has hydraulic shock absorbers on the first and last road wheel stations but on the STK upgrade these are provided at all road wheel stations to enhance ride comfort. In addition the rear idlers have also been reinforced.

The existing steel tracks have been replaced by Soucy rubber-band tracks, which are claimed to have a track life of 8,000 km. Not only are these rubber-band tracks lighter but they have less vibration and are much quieter.

The improvements to the suspension are claimed to provide a much-improved cross-country ride for the crew.

The M113 APC originally had the diesel fuel tank installed inside of the rear troop compartment on the left side.

As with all other M113 upgrades, this has been removed and replaced by an armoured fuel tank located either side of the power-operated ramp at the rear of the hull. This feature provides additional space inside the hull, as well as reducing the risk of fire.

The upgraded M113, shown for the first time in February 2006, was fitted with four firing ports on either side of the rear troop compartment with a bulletproof vision block above.

The crew is seated on suspended benches down either side of the hull facing inwards and provided with individual seat belts.

The first prototype of the STK upgraded M113 was shown fitted with a special cooling seat belt, which provides the occupant with personal cooling under closed-hatch operation when operating in an extreme high heat environment.

The baseline M113 series APC is normally armed with a 7.62 mm or 12.7 mm MG. No protection is provided for the gunner.

The STK upgraded M113 is fitted with the locally developed 40/50 one-person cupola, which is armed with a 40 mm automatic grenade launcher and a 12.7 mm MG. A bank of three 76 mm electrically operated smoke grenade launchers is mounted either side of the turret.

In its baseline version the 40/50 cupola has been built in large numbers for the STK Bionix infantry fighting vehicle and M113 series APCs.

The 40/50 cupola has powered traverse and elevation but in its standard configuration the gunner is not provided with full armour protection from small arms fire and shell splinters from above.

The 40/50 cupola fitted to the upgraded M113 is fitted with a new transparent armour kit that provides protection from small arms fire and hand grenades. It also has a flip-up roof with or without protection coverage.

In addition to the installation of the 40/50 cupola, the vehicle can be fitted with a wide range of other turrets and cupolas including a RAFAEL Overhead Weapon Station (OWS) armed with an ATK Gun Systems Company 30 mm MK 44 cannon and 7.62 mm coaxial machine gun. This is already in service with the Singapore Armed Forces on some of its M113 series vehicles.

Other potential improvements include a rear and front view camera, as well as a variety of appliqué armour solutions including mine protection, front and side armour protection and transparent armour. Due to the new power pack and upgraded suspension, the M113 is capable of having a significant amount of additional armour without compromising its mobility.

The STK upgrade is aimed at the baseline M113 series APC but automotive aspects of this upgrade are applicable to most other members of the family, such as the M577 command post vehicle and mortar carrier.

Development of the STK upgrade is said to be complete and it has already undergone extensive trials in an undisclosed country. The company can either carry out the upgrade work itself or provide kits to enable this work to be carried out in the user's own facilities.