Sounds like fun.
I remember a very drunk night years ago when visiting a friend in London, the tide was right out exposing lots of the Thames river bed. I'd seen that people had been finding historical artifacts, so about two in the morning very drunk we decided to go searching....
I remember finding all sorts, including a sword.
I woke up on his floor cover in mud with a pile of crap, including a railing (the "sword"). On top of this I had no change of clothes and had to travel back home to norwich on the train the next day.
....On the positive side, I didn't need to share my seat on the journey home.
Magnet fishing sounds better.