So does anyone know the name of that German(?) movie??

It starts off with a family driving to a lakeside house, with a big security fence around it. Mum, Dad & woosy son in the Range Rover listening to classical music as they drive to the holiday house.

A couple of young guys come in through a hole in the fence, supposedly to borrow some eggs- but turn out to be nutters. One smashed the father's knee with a golf club & they tied the wife up.

They keep coming & going in a small sailboat across the lake.

It's a horror movie, & maybe not the greatest, but kind of intriguing.

Any great minds out there know what it was called??

Oh- & don't forget 'The Collector' an old B/W classic kidnap movie.