I don't know about boats and boat things, but I have had several breakins in Seattle, two in my office and two in my labs. The thieves, which police say were likely professionals, took only items that hadn't been indelibly marked, and left far more valuable marked items. The officer that investigated said if they were caught with marked items police simply had to call or email the owners and that would tie the person to the theft. It is also nearly impossible to unload these items to pawn shops. We also had items stolen out of backpacks students had stored in a room a few years ago during a honor ceremony, and only unmarked cellphones and computers were taken. Using a scribe (i.e. Dremel) or equivalent might help. My radio, charter, etc., are all etched with my name, cell phone and email.