Whether you pronounce "winding" as if it refers to the "wind" as in the blowing variety or "wind" as in winding a clock, it is a place for turning round. The former seems to have more votes than the latter but it makes little difference.
Winding holes are another opportunity for the Considerate Boater to give due consideration by signalling to other boaters of their intentions. There are horn signals that can be given, see "Sound Signals" in the CRT "Boaters Handbook".
However, be aware that many will not be familiar with the signal for turning.
In this case, a hand being rotated in the air above your head seems to get the message across.
If the boat ahead of you is the one doing the turning then stay well clear. It may be a novice boater trying it for the first time. Many hirers do not get a lot of practice, especially if they are following a ring route.
Anyone slowing the progress of other boats by turning may put the others in difficulty on a windy day so be prepared to act in a considerate way.
Know where the winding holes are situated and plan ahead.
If you are the one doing the turning then signal others as early as possible. If there is a boat close behind or coming toward you then consider if it is possible to let them pass before you start your turn. If you are mid turn and a boat appears then consider holding your bow up against the head of the winding hole and letting them through.
If you are following another boat toward a winding hole then remember that they might need to turn and stay clear as you approach the hole. It could save you being trapped mid-stream with the wind blowing you sideways.
Often, opposite and inside winding holes, there can be the only length of canal-side piling for miles. Do not moor on the piling. It is there to maintain the turning area. You will get no sympathy from the working boater as he/she arrives to turn their working 70 foot boat and butty.
Never try to "slip" past the other boat mid-turn unless they clearly wave you through.
Don't use marina entrances or moorings to turn unless it is a recognised winding point. It is so easy to get it wrong when the wind from the marina hits your bow and the owners won't be happy if you hit the side of the entrance.