Broads Beat, the Norfolk Broads police force is encouraging boat owners to not only secure their vessels but list items and serial numbers.“Officers have recently recovered an outboard engine that was stolen off a boat moored on the River Thurne at Potter Heigham in 2016. This was initially found by marine police doing spot checks on boats in Lithuania. Officers managed to identify the engine due to the serial number, again reinforcing the importance of them.”
Wintertime is a vulnerable time for boat owners in most locations and the remote locations of the Norfolk Broads is particularly vulnerable especially being a lot more relaxed to other boating areas in the country.
It is actually quite easy to implement security measures that notify you immediately if an intruder mounts your craft.
I would recommend one called Salient Eye, it is manageable and sustainable even without mains power.
Anyone makes an unauthorised entry and they are photographed and you are emailed with the photo immediately. It makes nothing infallible but gives you a major advantage in crime prevention and also a strong possibility to notify the authorities when a crime is taking place.