In my mind, boat monitors fall into one of two categories: high-end systems that can do everything and simple systems focused on key systems. The former category typically includes all manner of sensors, network interfaces, and other options. Monitors in the latter category focus on monitoring critical indicators of a boat’s health. Depending on the size, complexity, and use of a boat, there are scenarios that fit both categories. Sensar Marine’s Boat and Bilge Monitor focuses on critical systems and may be the most refined example I’ve tested. Overall, I was pleased with how the monitor worked while seeing a few opportunities for even better performance.