A fog cannon sounds like a good idea– at first
I give you an antebellum cannon, long on display in USCG’s PACAREA. This vintage 24-pounder siege gun was first used as a fog signal on Point Bonita, California, the entrance to San Francisco Bay, during the time of the Gold Rush clippers.
Beginning on 6 August 1855, a retired Army sergeant was detailed to fire this gun every half hour whenever fog prevailed. What they didn’t take into account is that Point Bonita averages 1040 hours of fog signal operation every year, which placed a considerable burden on said sergeant.
As noted by the U.S. Lighthouse Society:
Armed with his marching orders Sergeant Mahony set about his task. What the service didn’t know was that Point Bonita experienced over 1,000 hours of fog or “thick” weather a year.
In short order, the district office received a letter from the good sergeant stating, “I cannot find any person here to relieve me, not five minutes. I have been up three days and nights and had only two hours’ rest, and am nearly used up. All the rest I would require in the twenty-four hours is two, if I could only get it.”
During the first year, he fired 1,390 rounds, expending 5,560 pounds of black gunpowder at a cost of $1,487. The district did send him an assistant, but in the second year of operation, there were 1,582 discharges expending $2,000 of black powder, three times the sergeant’s salary.
This procedure was discontinued in March 1858 due to the high cost of powder. No mention of what happened to Mahony, who likely said “What?” a lot when spoken to.