BERG Azimuth Thruster System – BAT (Photo 1) is a steerable thruster with a custom made controllable pitch propeller. The thruster unit is available in both L-Drive & Z-Drive configurations and can be powered by an electric motor or a diesel engine BERG Transverse Thruster – type BFTT (Photo 2) is a fixed pitch propeller type thruster used when shaft speed is variable and ease of reversing is important. The propeller unit with the gear housing can be removed from the tunnel while installed in your ship, making maintenance and service easier and less time-consuming. Berg Transverse Thruster system – type BTT (Photo 3 and 4) is a controllable pitch propeller normally used for constant shaft speed. The propeller unit and the gear housing can be removed from the tunnel when installed in your ship making maintenance and service easier and less time-consuming.