March  2018
I was a late comer to using kites as sails, didn't make a start until 1987, when it seemed to me that enough ducks were in a line to make a major shift to kite traction achievable- having also temporarily run out of interesting single line kite challenges.
By then I'd been strongly influenced by Paul Macready winning the Kremer prize for the first man powered aircraft to fly a one mile figure 8 course in 1977. MacCready's "build quick and dirty" approach was what enabled his success where well-funded attempts by various other experts and institutions had failed.
These attempts had, conventionally, split their projects into design, build and fly phases. MacCready mixed these all up, establishing a team that could design make and test ideas quickly and cheaply through multiple iterations.
In essence, this is the "Silicon Valley' "move fast and break things" system- which has spawned the tech giants that now dominate our lives. It is well established and widely copied now, but wasn't back then, when innovation and business development were much more ponderous processes.
I was very taken by MacCready's example, and went about getting or improving various useful skills; machining, fibre glassing, stainless steel fabrication, tig welding, sewing of course- and lots of traction kiting; so as to be able test stuff myself rather than having to interpret other people's impressions. I was very aware of the handicap that Jalbert (inventor of ram air kites) imposed on himself by not sewing.
Having all these skills "in house' cuts development costs enormously and speeds the process up.

Successes flowed immediately: Kite buggying for example, and Peels and C Quads, and Arcs.
And failures; 20 years trying to get kite sailing established, with a succession of monohull and multi hull craft that worked technically and bombed commercially.
But, with the benefit of hindsight, this "try as many new things as possible and move on quickly when something doesn't work" approach also laid the groundwork for another failure:

A kite traction platform I thought of using was something based on the sit-down hydrofoils that were developed for water skiing from the 1960's. These were reasonably widely known by the late "80s and commercially available as the AirChair from 1990. I recall seeing one built by a local waterskier in the late "80's, and kite fliers I knew did try variants. Their verdict was always the same; "Yes it's possible to get up on one using a kite, but control is virtually impossible". So, everyone's efforts went instead into unidirectional planning boards, then bi-directionals; developing kites, boards and skills in a leapfrog process that by the millennium had begun to establish kite boarding as a sport.
Kites were improving rapidly: The key to kite traction is de-power (enabling fliers to control the amount of pull), and the first really successful de-power kite was Bruno Legaignoux's "Bow" that came out in 2002, developed from his original 1980's breakthrough inflated leading edge single skin "marine wing'.
As kites (and flying skills) improved, it gradually became possible to use hydrofoil boards- though only in smooth water and light to mid-range winds. A dedicated user group then established but made little impression on the world until a further small technical step occurred.
Which was fully bridled de-power ram air kites (first developed for buggying and snow kiting ➜ Lynx Depower Foils) coming into on-water use from around 2010. Derived from Jalbert's 1950's invention that also led to sky diving "foils, paragliders and single line ram air inflated theme kites, "foil kites go to windward better than Bow kites can.
This combination of improved aerodynamic efficiency and hydrofoil boards makes for sailing that is faster around a course (and in a straight line) than almost every other sailing craft excepting Americas Cup foilers. And in a package that can be carried on a bus or bicycle.

Which has been one of the biggest surprises of my life- not just that it's happened, but that it's happened so quickly. Just 30 years ago, kite boarding didn't even exist.

I deserve a caning for not having seen this coming, even though I had all the elements in my hands, before 1990- except the depower "foils, but I was working on them too.
It's Paul MacCready's fault!

But I'm in excellent company because, even more astonishingly, hydrofoil boards are now being used for open ocean surfing! How come nobody did this 10 years ago- or even 100 years ago? There is no technical reasons why they couldn't have, because hydrofoil principles and practice were widely known by 1910 when Alexander Graham Bell (inventor of the telephone) popularised their use for powered boats.
And surfing applications didn't need to wait for engines or de-power-capable kites to be developed. The traction force is gravity in the form of a slope (generally called a wave).
Nor is it necessary to go to some special surfing spot with regular breaking waves and offshore wind. A swell of 500mm or so is enough, and it's easier if it's not breaking- which is a description of the sea pretty much everywhere, all the time. It's even possible to ride one wave then "pump" back out to catch the next one without dropping off the foil. Except that its undoubtedly more difficult than it looks- slick youtube presentations notwithstanding- but it's in its infancy and can only improve from here. I can see no reason why ocean crossing won't eventually become possible- limited only by human endurance.

I've always known that better answers can sometimes come from refining existing solutions rather than by breaking new ground, but it would have surprised my younger self to know that two of the greatest advances in kite flying in my life-time (de-power "foils and hydrofoil kite boards) would come from incremental development rather than original acts of invention. Back then I regarded the field of kite traction as an unploughed field in which every furrow would turn up some exciting new discovery, while refining existing ideas was boring.

Somewhat of a character flaw that- how much more progress could I have made with clearer thinking!

But better late than never:
So I've changed how I'm going about single skin single line kite development to trying small changes in panel shapes, leading edge construction, tail attachment, and bridling, combined with exhaustive comparative testing. And just one year of boring incrementalism has yielded more improvement than the previous 3 years of much more exciting "rip it up and try something different".

There's an Octopus that flies great, really stable, with a wide wind range, but has a seemingly terminal tentacle tangling problem. A Serpent that's excellent until the wind drops, when it slides off to one side or the other- which doesn't improve relations with neighbouring fliers. And 1Skins, the most interesting form because they herald a generic type rather than a specific design, which occasionally dive over to one side in strong winds. Another year or ten of this and the Serpent and 1Skins at least will be in business I reckon.

Damn, but I hope I can stay on the wagon!