Some canals have single locks, in pairs. This design offers a chance to chat with other boaters, since 2 boats can go up, or down, at the same time.
Chatting with another boat, I see and hear: she recovered from a stroke, hobbles, struggles to wind up the paddles; he recently fell and injured something unspecified.
Later, they moor their neatly kept boat nearby. As I help them tie up, I can see … this season may be their last.