stood primed and poised

Yes it is, and I apparently did not read your previous post closely enough.
I was unaware of the "fancifully claimed" origins for some of these phrases, and took the nautically-based explanations in good faith.
Perhaps I am more gullible than most, or tend naturally to prefer a more colourful story.
Finding definitive proofs might be difficult, but I'll look up some more in the above-mentioned book.

stood primed and poised
The QPB Encyclopedia of Word and Phrase Origins gives the following:

"This expression, originating in England, literally means to go overboard, to fall down past the board, or side of a ship, into the sea. since the mid-18th century it has also figuratively meant to be utterly lost, as in the first recorded use of the expression: 'Every instinct and feeling of humanity goes by the board.'"

Again, the naval reference. . .