Mercury - 1st Mate Safety & Security System SmartCraft 4/5/6-Engine Kit 98-8M6007938. Overview. Multi-engine offshore boats carry a lot of power and a lot of people-and the 1st Mate system gives you an added layer of protection to match. The Mercury 98-8M6007938 1st Mate Kit is built specifically for four-, five-, and six-engine SmartCraft installations, bringing man-overboard alerts and engine-lock theft deterrence into one integrated package. With the vessel hub, harness, captain's wearable, a