Daniel i think you've done the correct thing in arming and upgrading your security at home, make it hard for them and they will go else where, most burglaries are crimes of opportunity, if they think or know there's something in there worth having they'll have a go at it, like wise if you make it easy for them to get in they will again have a go, make it hard and they are more than likely to go next door.
The only exception to this is if they know its in there and they want it, then there's not much you can do as a dedicated thief will come armed with the right kit to get it and the determination to brake your security.
Again if you keep your boat off sight be careful who you tell where it is, IMHO i'd be more trusting going to the owners address to view a boat for sale rather than a dodgy lock up garage around the back of knowhere's vile
(no offence meant to owners of lock up garages
lastly if you need somewhere to store it for a short while whilst upgrading security or while waiting for the immidiate threat to pass you can alwasy leave it at my place (and the keys)