True, I remember the incident, but this is a sightseeing pleasure boat carrying upwards of a hundred-odd people.  A mortar bomb isn't exactly something that can be packed into a holdall.  I might be wrong, but it sits on a tripod on terra firma.   Somebody mentioned about the Health and Safety boys getting in on the act checking the number of decibels it sets off.  I'm surprised they haven't insisted on somebody having to shout a warning that a cannon was about to be detonated in case the shock would give some little old lady a heart attack! :^O  Then of course there are the birds - forced to flee their nests, leaving their fledgeling to perish.  Think about it - you could spend an entire evening working out all the woes that would come about by letting off cannons willy-nilly.:-D  What about the carbon footprint - are the shells ozone friendly, or does each one pollute the atmosphere a little more?

I once knew a fireman who successfully sued the LFB after he suffered hearing loss due to the sirens being tested every day at the fire station which, because it was in an enclosed area, amplified the sound.  Where do you draw the line?