When did cannons fall from use on merchant ships?

May 2019
108
Earth
#1
Skimming through sources on 18th century shipping, it seems that it wasn't unheard of in that era for merchant vessels to carry a few guns for self-defence, particularly if operating in known dangerous waters such as the Caribbean or Indian Ocean. However, by the time we get to the age of steam in the mid 19th century, mentions of cannon on merchant ships become much scarcer, fading into non-existence as the 1800s go on.

So, how late after the 18th century could you still see mercantile vessels carrying guns? To be specific, I'm only asking about merchant vessels under civilian control, sailing on mercantile voyages. I'm aware that guns were mounted on commerce raiders and other militarised merchant ships well into the 20th century, but that's separate from my question here.
 

Chlodio

Forum Staff
Aug 2016
4,320
Dispargum
#3
A couple of things happened in the mid-19th century: naval weapons were becoming more expensive and more difficult to operate effectively unless the gun crew was extensively trained. Also, in the Treaty of Paris (1856) that ended the Crimean War, many European countries outlawed privateers - the use of civilian ships and civilian crews as warships. It was now likely that a merchant ship would only be attacked by a naval vessel, and it was highly unlikely that an untrained civilian crew would outfight a naval vessel, so putting a few guns on a merchant vessel no longer made sense. Most merchant ships were insured, and insurance companies discouraged merchant ships from fighting.
Around 1900, the Geneva Conventions banned acts of war by civilians. Guns on merchant ships had to be manned by naval crews which was only done in wartime.
 
May 2019
108
Earth
#4
They never did. Even today, merchant ships in high risk areas like Somalia still carry anti-ship weapons to discourage piracy. The prevalence of use, from the Bronze Age onwards, has always ebbed and flowed in conjunction with the perceived safety of the shipping lanes.
Merchant ships today carry things like high pressure hoses and barbed wire to discourage pirate attacks. Armed guards sometimes (though this can get a bit messy depending on a country's laws concerning armed vessels). I have never talked with sailors who served aboard a mercantile vessel carrying artillery in this day and age. Where did you hear about commercial vessels carrying cannons in the 21st century?
 
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Dan Howard

Ad Honorem
Aug 2014
4,683
Australia
#5
Widespread arming of merchant ships. Insurance companies are offering cheaper premiums to ships that carry security contractors.
Merchant Ships Starting to Carry Armed Guards against Somali Pirates (11/22)

Armed Guards Now Deployed on 80% of Container Ships and Tankers

Private contractors serving aboard merchant ships with M16s and belt-fed machine guns. Describes one incident near Mombasa in which they repell a pirate assault after a 30 minute firefight.
Have hired guns finally scuppered Somali pirates? - Reuters

"The yachts trawl at a deliberately slow speed, hoping to attract pirates. If attacked, the cruise passengers are ready to respond with heavy machinery: machine guns and grenade and rocket launchers."
Paying money to murder: Russian luxury yachts offer pirate hunting cruises

Russians shooting machine gun and RPG at pirates
 
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May 2019
108
Earth
#6
Widespread arming of merchant ships. Insurance companies are offering cheaper premiums to ships that carry security contractors.
Merchant Ships Starting to Carry Armed Guards against Somali Pirates (11/22)

Armed Guards Now Deployed on 80% of Container Ships and Tankers

Private contractors serving aboard merchant ships with M16s and belt-fed machine guns. Describes one incident near Mombasa in which they repell a pirate assault after a 30 minute firefight.
Have hired guns finally scuppered Somali pirates? - Reuters

"The yachts trawl at a deliberately slow speed, hoping to attract pirates. If attacked, the cruise passengers are ready to respond with heavy machinery: machine guns and grenade and rocket launchers."
Paying money to murder: Russian luxury yachts offer pirate hunting cruises

Russians shooting machine gun and RPG at pirates

Oh, so you're just referring to armed guards? Well, I don't normally consider guys armed with M16s and RPGs to be "artillery" or "cannons", but whatever :p
Not what I'm asking about in this thread.
 

Dan Howard

Ad Honorem
Aug 2014
4,683
Australia
#7
"Artillery" is a pointless distinction; you should be looking for examples of "anti-ship" weapons, not just cannon. Rocket launchers, grenade launchers, and heavy-calibre machine guns fall into that category. Anti-ship weapons have been used on merchant ships to discourage piracy since the Bronze Age and they never stopped being used.
 
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Dan Howard

Ad Honorem
Aug 2014
4,683
Australia
#9
I do not think it "murder" to shoot down pirates.
They aren't pirates until the evidence is tested in a court and it IS murder if your response was not proportional. E.g. you can't kill someone just because they came alongside and said that they wanted to come aboard.
 
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May 2019
108
Earth
#10
"Artillery" is a pointless distinction; you should be looking for examples of "anti-ship" weapons, not just cannon. Rocket launchers, grenade launchers, and heavy-calibre machine guns fall into that category. Anti-ship weapons have been used on merchant ships to discourage piracy since the Bronze Age and they never stopped being used.
Pointless to you, not to me. As I said in the op, I'm interested in historical accounts of cannons being carried on mercantile ships post-18th century. Cheers :)