You could
research 'star pointers' - Artic makes a 2 watt green laser that apparently throws a narrow beam 55 nm for 30 min on max
power (which is adjustable). It has a coded lock so only you or your wife can turn it on so the
kids can't get in trouble with it. It has an SOS mode you can demonstrate at
low power to back up your claim that it is just a piece of 'safety equipment'. Such a light at higher
power settings is likely to render the vision of any miscreants inoperable for some period of time. It has better range than most firearms and is likely
legal - although non-lethal. With early warning of approaching intruders, perhaps a dog or other
alarm system and some degree of alertness, any miscreants can be discouraged from possible evil intent. I also suspect that it can be useful for discouraging other creatures with eyes from annoying behavior - birds, for example might be discouraged from roosting in the
rigging; insects, for another example, might be blinded in order to more easily dispatch them. Such an implement might give piece of mind so you can enjoy your
cruise with your
family knowing that you are not at the mercy of third world petty criminals.