10 of the present invention attached to a bimini top 4 of a typical boat 6 is shown the bimini top 4 is shown supported by a series of rails 2 the attachment mechanism 50 of the marine alarm system 10 is clipped to an edge of the bimini top 4 by the clip end 54 and is held in place by the spring 52 referring to fig4 a perspective view of the system of the present invention attached to a rail 2 of a typical boat 6 is shown for theft prevention reduction the marine alarm system 10 is mounted on a rail 2 of the boat 6 facing the stern of the boat 6 in this example both the motion detector 14 and the light 16 are aimed toward the stern of the boat 6 so that when an intruder boards the boat 6 the motion detector 14 detects the intruder and warns either the cabin occupants or anyone in the vicinity of the boat 6 that something is wrong this visual and or audible warning from the sounder 26 and or the light 16 is often sufficient to ward off the thief and or notify occupants and or anyone in the vicinity of the boat 6 to notify the proper authorities referring to fig5 a first schematic view of the present invention is shown in this exemplary circuit power is provided by for example the boat battery at 12 vdc in this example the 12 vdc power is routed through an optional.