Been fussing over boat music lately. I absolutely did not want to cut in speakers or hang them from somewhere. Finally found a solution!
I have a Kenwood/Sirius radio installed in the helm and added a Bluetooth transmitter to the line outs on the back. We have one of those fancy Bluetooth speakers that connects to the phones or iPads and now connects to our stereo.
No wires, no holes and no headaches! Best thirty bucks I've spent in a long time.