Here in the Caribbean most thefts from boats seem to be of the swim/row out and pilfer variety, though sadly, there seems to be a trend towards a more boat-invasion model.
The only thing we have had stolen off of "So It Goes" since we have had it was a mask and snorkel of mine which I am pretty sure I must have left on the side deck instead of putting it away in the dive locker (my bad). I would not be surprised if the reason for the theft was the fact that I left our boarding ladder down rather than stowed on the lifeline... again my fault.
Of course, we make an effort to keep "So It Goes" less than pristine as the last thing we want to look like in an anchorage is well off or rich and simply prefer the boat to blend in with all the others without any signs that there is anything worth stealing aboard. For the most part, we always anchor as far out as possible and away from the herd as in my experience, having known no shortage of villains, I do know that in most cases your average thief prefers less work rather than more and won't make the effort to swim/row out to us if there are closer (and more lucrative) targets about.
Since "So It Goes" is an older (1969) sailboat we also do not have the sugar scoop stern so popular these days, which just screams stealthy easy-on/easy-off access to villains. To board us they have to come over the side which is more likely to let us know someone has come aboard and is much more visible from a distance.
The only other real precaution we take is that we do not have a name on our dinghy as nothing says "Come Out and Steal Stuff" as your boats name on the dinghy sitting all day at a dinghy dock!
Which is not to say we have not had the odd cunning plans to make "So It Goes" even safer but so far nothing that has quite worked. Though the exclusion zone by radio controlled model boat seemed to have promise, and to be honest, the one with the anvil from the masthead WAS something of a disaster!
The current plan of teaching Ninja repel-boarders-martial-art-techniques to Buffy and Willow has not yet seemed to get past the wax off wax on stage but we are working on it.
On the other hand, while not quite so cunning, the idea of making your lifelines do double duty by turning them into an electric fence actually does seem like a reasonable approach and solar powered systems are both cheap and workable... In my case of course, I'd be much more likely to forget to turn it off and do myself some damage coming back to the boat but it is a thought that just might work.
