Abstract: An active automated anti-boarding device for a maritime asset security system includes a housing for mounting the device on a maritime asset. The deterrence device includes visual and sound deterrence emitters within said mount to disperse a directional fan pattern of sight and visual deterrence response outward from the housing to unauthorized boarders. An active automated anti-boarding maritime asset security system includes detection devices configured to mount to maritime asset, the detection devices each including emitters and receivers for generating and detection beams that form a virtual fence to form a detection network on a portion or around an entire maritime asset. Deterrence devices responsive to the interruption of the spaced apart detection beams produce a deterrent response that is non lethal. The deterrence response can be a law enforcement level of deterrence, it can induce discomfort and/or disorientation to deter unauthorized boarders.