I've watched some videos of a team that does that here in Georgia. They once found a grenade in the Hooch in Atlanta.Magnet fishing is becoming more popular now. They find "fishing gear" in the rivers and lakes quite often. Normally they call the local LE to report it just in case there's a history of the "reel" catching a "big fish." Wink wink.
I've seen a couple where they had a tow truck come and pull a car they found out of the Savannah River. Many times, if they get something heavy they can't pull up on a cable, they will dive to take a look at what it is and then go from there. There was one video taken in Savannah, where they found six rifles bound together at the bottom of the river. When they find weapons and cars, they always call the police.I always wondered what they do when it latches onto a solid metal object, do they cut the line?