Bilge High Water Alarm Sensor

Maretron BHW100 Bilge High Water Detector — SIM100 Accessory

A solid-state bilge water sensor that alerts the SIM100 Switch Indicator Module the moment water rises above the detection level — no float, no moving parts, no mechanical failure mode.

Why It's Worth It
Traditional bilge float switches are mechanical — they stick, they corrode, and they fail in the position that matters least, usually "normal" when the bilge is flooding. The BHW100 has no moving parts: a molded-in target on the sensor face detects water conductivity directly, illuminates a red LED locally, and simultaneously sends an alarm signal to the SIM100, which broadcasts it over the NMEA 2000 network to every compatible display onboard. A disconnected wire triggers an error state on the SIM100 rather than a silent failure — so a broken connection is just as visible as a high water alarm, meaning the system monitors its own wiring integrity the same way it monitors the bilge.

Important Installation Notes
Mount horizontally on a vertical bilge wall with the Maretron label facing the wall and the molded-in target facing outward into the bilge — this orientation lets water run off the face quickly so the sensor clears promptly after water recedes. Cover the mounting screws and metal sleeves with silicone after installation: water bridging between the target and screws can cause the sensor to read "still wet" until the water evaporates, which slows the return to normal state. The BHW100 requires the SIM100 channel mode to be set to "End of Line Resistor" — not "No End of Line Resistor" as used by the magnetic switches in the same system.

Use
Wires to a free channel on the SIM100 — brown wire to the "A" terminal, blue wire to the "B" terminal (polarity matters, do not swap). Configure the SIM100 channel to "End of Line Resistor" mode via a Maretron DSM display or N2KAnalyzer software. Verify operation: out of water = "off" (normal), immersed = "on" (alarm), wire disconnected = "error."

In The Box:

BHW100 Bilge High Water Detector
Mounting Hardware
Documentation

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Qualifies for Ground and 2 Day

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* ALL WARRANTY IS THROUGH MANUFACTURE *