Mystery cannon

An archaeologist is taking a second look at a small cannon found by fishermen off the Virginia coast more than two decades ago in hopes of determining how it got to the bottom of the ocean -- and who left it there. . .

Some historians believe the 4-feet-long, 300-pound cannon, which was loaded when it was found 24 years ago, is an English cannon from the 1580s, making it one of the oldest English artifacts ever found in the Americas.

From MSNBC. Identifying the cannon is doable, and studying encrustations and such may tell us in very rough terms how long it was underwater. All the rest is going to be just conjecture, though, absent an exact find spot.