Yesterday at a family gathering I got to talking with my nephew-in-law, someone I don’t get to see very often.

He is in his 33rd year of working as a tugboat captain for the port of Venice, so I made the most of the moment, grilling him lightly on both sides with questions about the floating Alps.  Specifically, what sort of danger they present to the city — especially that nightmare scenario in which a ship the size of Madagascar goes off course and cleaves the Piazza San Marco in twain.

Here is what he told me:

1.  The ships have many propellers (I forget the number) and it is highly unlikely that they would all go out of service.  More than the propellers, I think it’s probably the motors one should be more concerned about.  Here too, the probabilities are notable:  Cunard’s Queen Victoria (my floating Alp of choice) has six diesel engines, as well as three bow thrusters.  Could they all stop at once?  I suppose, if you lived long enough.

2.  The big ships each arrive and depart Venice with two tugboats attached, one at the bow and one at the stern.  If the ship were to suddenly go dead in the water, the two tugs would be capable of keeping it on course. Pushing, like two little sheepdogs.

3.  The last factor which is perhaps unique to Venice (at least in the big-cruising world) is that what’s down under the surface is mud.  The channel along which the ship traces its passage provides a rather narrow strip of sufficient depth; tide and the action of many motors have pushed mud up against the embankments.   We don’t have rocky shores, like some islands I won’t mention, which dealt the fatal blow last January 13 to a ship whose name I will not utter.  So even if a ship did suddenly head straight for the Doge’s Palace, it would run aground in the mud before it got there.

I have rowed a little mascareta at full speed (arguably not comparable to that of the Queen Victoria) up onto a mudbank.  You’d be amazed how fast the boat stops.  Which I mention to confirm that mud has phenomenal braking powers.  And when you try to pull the boat off the mudbank, you appreciate that even more.

So I’ve stopped caring about the buoyant metropolises that steam past us all summer.  I’d be a thousand times more afraid to find myself in the path of an illegal clam fisherman at night, as he races across the lagoon with his 300-horsepower engines trying to get away from the Guardia di Finanza.  I promise you, he wouldn’t even ask his friend “Did you feel something?” as he went over you and kept on going.  But I shouldn’t change the subject — because the world is lying awake at night worrying about Venice, not about me. I merely note that on the “clear and present danger” list, big-ships-sundering-Venice is pretty low.