<Phillip wrote: .....I'll put a long distance proximity detector centered on the cockpit and the swim platform. Magellan has a distance detector that will work out to 150' and I'll hook it into an inside alarm and loud outside alarm. Hopefully, the noise will accomplish the same thing a dog would and give me a few extra minutes to prepare before they are actually on board.> We tried a couple of the different type detectors. Seems that they aren't up to the motion of swinging at anchor, differing water temperatures and waves. Again noise isn't much of a deterrent. Look at how folks just walk by car alarms today. However what ever type of detector you have if it triggers a barking dog sound you'll have a deterrent. Go try it sometime. Next time a friend comes to the door set it off and see if they don't back off instantly ;-) Nobody likes big bad dogs except the owners. As always YMMV Cheers Dave & Nancy Swan Song Roughwater 58