A loose cannon (in a storm could fall down the hatches and crash through the hull). Swing a cat Taken aback
Yes, she's backtracking now! We've got a book here called "POSH and other language myths." Apparently the brass tacks is right though.
Jesus! slated in my absence! Ok, Ive checked these ones out ....keel over and on an even keel. Keel over, because if the keel went sideways the boat was going to capsize....on an even keel, the exact opposite, plain sailing ( to use another one )
Shake/show a leg from the days when women were allowed on board ships in harbour when they were required to leave. A wide berth.
And when women were about to give birth, they were taken to the gun decks because that was the only place that was kept clear and clean, ready for action. As the father was rarely known, if the baby was a boy he was called 'the son of a gun.'
Talking of transporting stuff by sea, that was how the tank got its name. When these new-fangled fighting machines were invented in the first war, they didn’t have a name but they had to be kept secret. When they were loaded on board to go to France they were referred to as ‘water tanks’ And the name stuck. The German panzerkampfwagen ‘armoured fighting vehicle’ would be a more logical name. Bit long though.
Lucky bag A lucky-bag is a receptacle on a man-of-war for all clothes and other articles of private property carelessly left by their owners, so-called because these articles were later auctioned off says A Sailor’s History of the U.S. Navy, “thereby making those Sailors fortunate enough to obtain new items for relatively little money ‘lucky.’”