Thank you for pointing that out. The date should be 1747. My editorializing aside, I see no problem with the rest and neither does the U.S Army Historical site.

Can anyone explain the origins of “left of boom/right of boom”, please?

Not I, but here‘s an explanation of the term, which I assume started in the military.

Imagine a continuum in the form of a timeline. In the center of the timeline is a fixed point that represents kinetic action, or the ‘Boom’. To the left of the Boom are events that influence the kinetic action. To the right of the Boom are events that are influenced by the kinetic action.

And here’s me thinking “boom” meant just the noise of the bomb.  We live and learn.

In support of my hypothesis about the military, I did find this post by Julian E Barnes dated January 2005:

Late last year, as the limits of technology became more apparent, the task force began to emphasize a new strategy, focused less on surviving or stopping an individual bomb and more on targeting the bomb makers. The military calls it working “to the left of boom” --that is, before the explosion. “When you work against people,” says Benner, “you work on offensive and you have a greater effect.”

Brilliant catch Eliza.  FTR, Grant Barrett has just added this to his Double Tongued Dictionary and connects us to the Washington Post’s Glossary which I didn’t know existed.

I could try to extricate myself by saying that I was talking about “military,” not “naval,” but that’s not exactly true. I wasn’t thinking about the navy at all, actually, but I think my point still holds.

The fact that there was a unit or two of organized military in the colonies prior to the revolution, or the fact that there was a Continental Navy (no one has pointed out the oxymoron here), doesn’t change the fact that the traditions of service of the US military are pretty much independently and organically grown and are not the result of a continuous military (or naval) tradition that stretches back to the British armed forces. As others have pointed out, you can trace unit histories back very far, but these are after-the-fact creations and omit breaks in service when units were decommissioned. They bear about as much material significance to the modern military as the genetic contribution of my great-great-great-great-great-great-great grandfather does to my genetic make up--once you go back more than a few generations, the influences are dwarfed by everything else that has happened in the interval.

One might make an argument that George Washington, who had brief experience with the British military in the French and Indian (a.k.a. Seven Year’s) War, introduced some British practices into the American military, but that’s a stretch--and about the best case there is. The fact is that following the American Revolution the US did just about everything it could to divorce itself from military traditions. We didn’t have a standing army based on a regimental system. US officers did not buy their commissions. Etc.

If anything, 1802 and the founding of the US Military Academy at West Point starts the continuous tradition of US military forces. This is roughly contemporaneous with the founding of the navy.

thanks all. Why do i feel none the wiser? i still don’t see why “left of boom” should mean offensive action, “right of boom” defensive action, and not the other way round. The definitions only explain the literal meaning of the expression, not why it’s used. Why not “in front of boom” and “behind boom”? “Above boom and “below boom”? “Before boom” and “after boom” (which to me, would make more sense ---not that one expects military jargon always to make sense)? the phrase has only been around a short while. Surely somebody put it that way for some reason (I hope they’re still alive).

BTW, Oecolampadius: In case you didn’t notice, ElizaD posted the link to that glossary, earlier on in this thread.

Ed.: just had a brilliant thought*! “Left of boom” is “before” because we write English from left to right! so in Hebrew and Arabic, we’d say “right of boom” for what is “left of boom” in English. And in Chinese, it would be “above boom” and “below boom”. If anybody is still writing boustrophedon, they’d probably do best to use some other expression.

* the third vodka did it.

Thanks for the note about me mantling Eliza.  I didn’t click on the link. Sorry dear.

but ...

Ed.: just had a brilliant thought*! “Left of boom” is “before” because we write English from left to right!

That’s what I said in my first note (second posting in this thread).

Makes sense in a world where one reads left to right.

i still don’t see why “left of boom” should mean offensive action, “right of boom” defensive action

Offensive/defensive isn’t quite right. Both offensive and defensive actions can be on either side of the boom.

Substitute proactive and reactive instead. Against an enemy armed with IEDs, a “left of boom” action would be to prevent the enemy from getting access to explosives, ride in armored vehicles, vary your routes and patrol times, etc. “Right of boom” actions would be hastily reassemble outside the kill zone, assess and treat casualties, find and return fire on the enemy who planted the IED.

(Never mind.)

And since visual representations of timelines typically go from past/left to future/right, left of boom refers to actions taken before the explosion and right of boom to actions after.

You can tell winter’s coming.  Everyone’s wearing a mantle.

Since Faldy is mantling himself, and knowing him as we do, he did it on purpose.  Or is that like explaining a joke?

edit: or is the reference to this: Imagine a continuum in the form of a timeline. In the center of the timeline is a fixed point that represents kinetic action, or the ‘Boom’. ?

Yes.  An x-y graph (Faldy’s original post) is not the same as a timeline (Eliza’s post and Faldy’s mantling thereof).

Dr. Techie, with his usual percipience, hits the nail on the head. In self-extenuation, let me plead health considerations.  The mantle helps to counter accelerated body heat loss, arising from subcutaneous peripheral vasodilation (the third and subsequent vodkas at their deadly work). “A mantle a day keeps pneumonia away”.
Faldage isn’t mantling himself; he’s only repeating himself, which isn’t really quite the same --- a little flatulence can happen to anyone, sober or tiddly.

I’m still looking for a Hebrew representation of a timeline. When you start to look for something, it’s never there (yticragogeid—not Welsh, just diegogarcity written R2L). Does anyone at this site write Chinese? Rongorongo?

Ed.: where’s the centre of a timeline?

(cheerfully) Don’t worry, I’m not upset.  Nobody ever has listened to a thing I say, anyway.

Bit nippy round here.  I’ve started a new enterprise - hand-knitted mantle and earmuff sets.  Anyone?

Edit: Lionello:

Ed.: where’s the centre of a timeline?

Boom, boom!

Further edit:
Now, now, Eliza.