In the Doldrums is not just a positional term for sailors, but a very particular place not just in the Atlantic, but stretching around the world at the Equator – The Inter-Tropical Convergence Zone – ITCZ or “Itch”. If you want to see the technical explanation see this excellent site. It is a region that all sailing ships passing from North to South (or vice versa) on the world’s oceans, could not avoid passing through. The air could be completely devoid of wind or the winds could be light and “flukey” (wandering in all directions) though equally, unexpected storms might release or deposit you in the doldrums. Because of the calm nature of the doldrums (mostly), great mats of Sargassum weed accumulate as an added hazard thereabouts so the doldrums are sometimes referred to as The Sargasso Sea.
Being trapped for long in the doldrums was a ship’s Captains nightmare, let alone ship-owners and cargo-owners and for the crew, being trapped under an equatorial sun with no cooling breeze and the water rations diminishing by the day – well you can scarcely imagine…
Below is a drawing of a ship fortunate to have found a light wind to take it out of the doldrums…
Idlers are yet another nautical term but with a counterintuitive meaning. Far from being lazy, idlers were those members of a ship’s crew whose work took place during the daytime and so were usually excused from working on the night watch – unless it was an emergency and “All hands on deck!” was called. So carpenters, sailmakers, cooks, and cabin boys were all idlers…
In the Offing – means a ship is within sight of port – many ports have a tower from which approaching ships can be sighted and the relevant people summoned to greet her shortly. A “Widow’s Walk” is an architectural term for a balcony at or above roof level where in the days of sailing ships, wives (sea “widows”), would watch for the return of their spouses – what a sad occupation…
We have two Cant examples for the letter “I”, from Wikipedia today…