Performance step changes.

Trying to find the link to the story about first kicker, I know it was used in a race in New Zealand, skipper kept it in his pocket to prevent anyone from finding out how they were winning.

Found it, Captain Boyd was inventor.

Sailed on Strangford Loch in Northern Ireland  in an old traditional class - think they were called "Rivers".  No kicker so crew would sit on boom to keep it from lifting up and depowering main.  If wind got up crew were lifted  up feet off the deck, add another crew member - downwind  these  crews members needed  confidence that helm would not allow a crash gybe.  Lovely boats to sail.

Oddly I think both trapeze and sliding seat may predate toe straps. Sliding sets date back to the end of the 19thC. What we would call trapezes were in use on Malaysian racing canoes about the same time. Its uncertain whether they inspired the european introduction, but they were reported in western yachting media, so its certainly possible.

Windsurfers brilliant, enabling use of wind from anywhere and could be carried in a van or roof of a car, then carried by hand, much like sit on top kayaks, 'Topper' probably nearest dinghy to meet this convenience.