This is a picture of a ferry with it’s front raised being boarded by people.
Initially, when I first looked at this picture I couldn’t see any identification, but when I’d scanned the slide and could zoom in with Lightroom, I found it is possible to read on the side of the ship the word ‘Olau Ke’. Once I’d started to enter that into google, it auto-completed the words Olau Kent for me and I found a page dedicated to this ship. It seems it has been owned, or chartered, by several different shipping companies and was in use by the Olau line from March 1976, which fits well with the date of this picture. In April 1976 the ship started working between Sheerness and Vlissingen, so I assume this is one of those locations and since this photo is followed by several which seem to be taken in Holland, I’ll mark the location of this picture as Sheerness.
Although this picture only shows people boarding, I assume that cars were also driven on the the ship, and that is why the front is raised.