Hi. I have done a fair bit of magnet fishing while narrow boating. I always come back with more windlass's and mooring pins than I left with.and a lot of junk too. Especially good when going through locks as you have enough time to do a bit of fishing while you are waiting for boat to clear.
Magnet fishing has cropped up in a new channel 4 programme - "Inside the Bomb Squad". Seemingly calls for service has increased as magnet fishing has got more popular. Some lovely shots of people pulling grenades out of canals! How they got there - god knows