Mercury - 1st Mate Safety & Security System Universal Single-Engine Kit 98-8M6007939. Overview. The 1st Mate system adds a modern layer of protection to any single-engine boat-regardless of brand. With overboard alerts, captain wearables, and an onboard hub that ties everything together, this kit keeps you and your crew safer the moment you step aboard. It also includes anti-theft features that help secure the vessel when you're away. Everything in this package is built to work on all leading en