Need more info; what do you have for an Antenna; 3ft, 8ft, radio; fixed or handheld, boat, where mounted on the boat. Can you transmit, how far? Can you receive the weather channels? You may have corroded connectors or a broken antenna wire.
The RF horizon (miles) for a transmit and receive antennas is: = 1.42 X sqrt(Tx antenna height (ft)) + 1.42 X sqrt(Rx antenna height (ft)). For two antennas (Tx and Rx) that are 10 ft. off the water then, the RF horizon is 9 miles.