A rub rail system for a vessel including a rigid track extrusion attached to a vessel, a resilient flexible fender extrusion, and a shock absorbing inner core. The subunit includes a subunit jacket defining a passageway interior thereto, an optical fiber extending through the passageway, and a first reinforcement material constraining the optical fiber within the subunit jacket such that the optical fiber and the subunit jacket are coupled to one another by way of the first reinforcement material. A first check valve having a first port operably coupled with the central tap of the Venturi device is configured to prevent pneumatic flow from the central tap through the first check valve. The visual alarm signal simulates the type of adverse condition being detected.