We have 'Anchor Alert' and 'Boat Remote'... Anchor alert we have used a couple of times. It's not the easiest thing to figure out, but does do well. Anchor Alert we have not tried yet, but want to. It uses TWO iPhones (and I assume Hemorrhoid devices too) and you can monitor your boat while you are ashore (one phone alerts the other what it is doing). It seems pretty cool, but like I said... we haven't fired it up yet. Be aware that the downside to programs like this is that running full-time GPS will annihilate your battery. You'll want to plug it into a power outlet for best results.