Do you remember Huckleberry Finn?

I distinctly remember him fishing with a bent hook attached to a pole via a piece of string. Well, it's a whole different ball game these days! For some reason I woke at 5am today and had trouble getting back to sleep. I kept hearing a strange, fairly low pitch humming or whirring sound and sometimes another identical sound would join in. It sounded like a pair of muffled electric drills or screwdrivers. I checked the boat over but failed to find anything out of the ordinary so went back to bed (and subsequently overslept!).
Later on I discovered the culprit.

It was moving very slowly back and forth across the fringes of the new marina and my first guess was that it was some kind of surveying instrument belonging to the marina company or perhaps C&RT. Wrong.

It's actually a remote controlled bait boat used by carp fishermen. You fill the hoppers with bait (and you baited hooks if you wish) then send it out to accurately deposit your payload. The guy using it also had this.

This is a fishfinder which utilises sonar! I googled the lot and reckon you would have no change from over £600. Kind of puts my bread punching exploits to shame!