Production information
ManufacturerDefiance Industries
Technical Specifications
Mass40 tons
ChassisDefiant V
ArmorValiant Lamellor
EnginePitban 240
SpeedCruising: 65 kph
Maximum: 97 kph
Jump JetsNone
Armament1xUltra Autocannon 5

1xStreak SRM 2

1xSmall Laser

The Sentinel is a medium 'Mech built by Defiance Industries, originally only for house Steiner, as a infantry support BattleMech. The Sentinel gained in popularity though and by the early twenty-eight century was being used in the SLDF and by houses Marik and Davion. The Sentinel has several features that attracted the use of so many interstellar nations. Among those reasons were the unique weapons that it carried at the time. The Sentinel had a critical flaw which was originally blamed on it's engine. After testing it was found that the Pitban 240 in use was not the cause but instead there was a flaw in the cooling system for the Sentinel that required a reworking of the cooling system in the units that had already reached the field and a redesign of the cooling system by Defiance in all future models.


The Sentinel carries a somewhat unique and some would even say haphazardly arrayed armament. The primary weapon on the Sentinel is a KWI Ultra class Autocannon 5. This weapon is capable of firing at double the rate of a standard AC/5. The system does have a slight chance of failure of the firing circuitry though that makes the autocannon useless until repaired. The rest of the weaponry is all short range including a Defiance B-1A Small Laser and a Defiance Streak SRM 2. The Streak SRM is also one of the things that attracted buyers for the design because the weapon will only fire if it gains a lock on the enemy and because of that lock all of the missiles fired from the launcher will hit the enemy unit.


  • 3025 TR(R)
    • STN-3K - The 3K Sentinel is the downgraded version of the 3L model. The Ultra Autocannon and Streak SRM have both been downgraded to their standard versions. The Speed of the 'Mech has meanwhile stayed the same and the armor has actually improved by one half ton.
  • 3050 TR
    • STN-3M - The 3M carries attributes of both the 3L and 3K Sentinels. The 'Mech carries the Ultra Autocannon 5 of the 3L model but also the standard SRM 2 of the 3K. In addition the Small Laser has been upgraded to a Medium Laser and the armor is the same as the 3L model.
  • 3062 TR
    • STN-4D - The 4D adds a Davion touch to the Sentinel. The SRM launcher has been completely done away with on this model and the Ultra Autocannon 5 has been replaced with a Rotary model. The Medium Laser from the 3M version has been upgraded to an ER model and the Five and a half tons of standard armor has been replaced with seven tons of Ferro Fibrous Armor.