I wonder if it's worth fitting dash type cameras on boats, you could have motion detectors to trigger the camera. Date time etc. Problem with dash cams on boats, you don't want the camera continuing to record for days after the event, as it will over write the footage, hence a motion sensor, or maybe a timer. A small pir sensor will draw very little current. Of course, best to have it on a small seperate battery well hidden from view.
How far do you have to go to protect your property, the important thing is to get these thieves arrested.
Marking batteries or any other possessions with boat name, post code etc would be a good start, it helps to put the thieves at the scence of a theft, if ever batteries or stolen goods are found.
I don't want to start a survey, but I wonder, how many boats have an alarm fitted, and is it set when people leave the boat?
Are boat alarms reliable, what happens if it goes off, and your marina calls you, but you are three hours away, you really want the alarm to hush after say 20-30 minutes, but then the thieves may come back later.
Who actually investigates an alarm anyway? if at home you need a group of friendly neighbours and an alarm that doesn't false trigger, I am a member of our local Neighbour hood watch, we do check and look out for each other. One neighbour, his alarm went off randomly, In the end, I volunteered to investigate, there were in fact two faults, a rear door reed switch and a pir sensor that didn't like spiders. I also fitted a new battery, and it has been fine for a couple of years since I fixed it. I also extended the alarm to include his garage.
Getting back to boats, how easy is it for someone determined to actually steal your boat? It happens, some are driven away, some simply towed, A lot of steel boats and many cruisers are generic, same starter panel, a simple key. Is it worth having a hidden defeat switch, difficult to do on older diesel engines unless you have an electric fuel cut off, or can disable the feed to the starter solenoid.
In Norfolk, there have been many reported outboard thefts, boats have been taken to remote areas and the outboard sometimes chainsawed off, with fixing bolts some times below the waterline, even if removed with spanners can result in the sinking of the boat too.
How many outboard owners have a seperate record of the serial number? The police in Norfolk/Suffolk managed to arrest a group who were stealing outboards, they were loaded into a container at Felixstowe ready to ship abroad. The Norfolk Police also sell waterproof covers to replace the solid outboard cover, as engines can be difficult to sell without a cover, and a new one can cost £100+ The owners swap over to their hard cover before starting the engine, but most would keep it on board doh...
If you are looking to buy a secondhand outboard, you can look on a well known auction site, and see engines for sale without covers, a few I have seen where the serial number plate has accidentally fallen off. So buyer beware.
We just need to keep an eye open, if you are not in a marina, where there is a type of caretaker, is it worth sharing contact details with close moorers?
Some will say... don't worry, just keep paying your insurance. To a point I totally agree.