Wiktionary
a. 1 (context nautical English) The "trapped" condition a sailing ship finds itself in when the bow of the ship is headed into the wind and the ship has stalled and is unable to maneuver. 2 The state of screw-powered ships which become stalled between crests of waves or swells during a typhoon, for instance, and the ship's rudder does not respond to the commands from the helm, leaving the ship at the mercy of the sea and in danger of capsizing.
Usage examples of "in irons".
If I determine you are unnecessarily endangering my ship and my crew, or forcing my people to act contrary to my direct orders, I will have you thrown in irons.
Of course they're in a bad way - what, they've seen their comrades marched off in irons, and they're upset.
If the bailiff or one of his watchmen were to hear you, we'd be clapped in irons and thrown in the gaol in a moment!
And when you waked and found yourself in irons, they would have tortured you before they hanged you!
The prince's men assumed I was rogue and a thief, and clapped me in irons.
Now, Elbow Island mates, is a barren reef where nothing grows but rocks, and there being nought to eat and little water in the casks, I boarded the Crescent Moon and sailed east by nor'east till I sighted this island Here I meant to help myself to what I needed, seize enough men to man my ship and go after those thieving rascals and bring 'em back in irons.
Archie was placed in irons and so securely guarded in his dungeon that escape was altogether impossible.
In my then capacity as sergeant of the guards, I had him thrown in irons, charged with high treason, and executed a week later.