I frequently get asked what happens if I get my magnet stuck and can't pull it out - well this is what I did after I plus 3 passers by couldn't pull it out.
I ended up driving my car down the harbour wall and attached my rope to the towhook. A conveniently placed mooring post made it so I could wrap it round and pull the magnet pretty much perpendicular to the harbour wall.
I had an interesting find that I definitely wasn't expecting; a fossilised tooth from what I think was a prehistoric marine reptile, not magnetic but fell off when I was removing chunks of metal from the magnet:
And here is the pile of scrap metal I ended up with:
This was a very good location, every single cast brought up multiple bits of metal, and I never moved from the first spot I stopped at along the harbour wall. I suspect I could go back thousands of times and still pull loads out.