There's a lot of shipping in that region. A lot of cargo containers are lost overboard. They don't all immediately sink to the bottom (sealed air, bouyant carg

There's a lot of shipping in that region. A lot of cargo containers are lost overboard. They don't all immediately sink to the bottom (sealed air, bouyant cargo, etc) What's the sonar signature of a 40 foot shipping container that's just floating below the surface? Are you even going to hear it without going active? What kind of damage does that do, if your submarine plows into it, even at a slow speed? My understanding is that the bow isn't entirely metal, that there's fiberglass (or something similar) where the sonar equipment is located.