Last year after a total kitchen make over, I purchased a half dozen 1st alert water alarms. Super sensitive, I refined them by placing the sensor on towels increasing the target area 10 fold,

those under the hull with hatches closed will never be heard, as there the volume is not near as piercing as a normal smoke detector any thoughts on a radio shack type amplifier I could put in line, perhaps get one alarm top side, each unit has perhaps 8 ft. between sensor and alarm.....

unit uses a 9 volt batt.