For centuries, surfing had been almost entirely the preserve of Hawaiians, whose happiness in riding the surf naked shocked visiting missionaries into banning the pastime. While other Polynesians, such as Tongans and Fijians, rode the sea on their bellies, it was in Hawaii that the art of standing on a wave was perfected.
The thin beach at Waikiki probably hasn't changed that much since The Duke set off for Stockholm, if you ignore the skyscrapers; the water still teems with outrigger canoes, surfboards and swimmers.
Sitting at its heart are the marble pillars of the Moana Surfrider hotel, where the Prince of Wales (later Edward VIII) stayed in 1920 and was taught to surf by The Duke. The grand, whitewashed 'First Lady of Waikiki' was the first hotel to be built here, in 1901. It has kept its imposing colonial style, with enormous corridors off the lobby to accommodate guests' steamer trunks.
It was here that I stayed before my first Waikiki surf - waking up to the sort of turquoise waves that make you want to leap out of the window and sprint for the nearest board shop.
This is where The Duke learnt his art, and, having spent the past decade attempting to surf with an enthusiasm far outstripping talent, I had long been keen to make that same pilgrimage.
Paddling out felt absurdly easy after Britain's freezing waters. The sea was a bath-like 25C - no need for blubbery layers of Neoprene. I headed for a reef break called Pops.
Two hours passed so quickly that when I finally found someone with a watch and caught a wave back to shore, I only had minutes left until my afternoon stand-up paddle boarding lesson at Hans Hedemann's surf school.
Hawaii-born Hedemann represented the islands as a professional surfer in the '80s and '90s, and now offers stand-up paddle boarding in tandem with the original art.
Waikiki claims to have invented the sport, since it was the beach boys here who are said to have first used outrigger paddles with longboards in the 1960s, to take pictures of surfing tourists.
Ever since celebrities such as Jennifer Aniston were pictured, paddle in hand, its popularity has soared.
"It is all about stand-up now," Hedemann says. "It's easier for the average visitor to try out."
It certainly looked easy enough - a bit like punting a landing craft - so I joined a group and we headed out to sea with Smiley, our enthusiastic instructor.
I managed about two strokes before falling off backwards. And manoeuvring the board into the waves was about as simple as parallel-parking an HGV, but when I finally made it work, I rocketed towards the shore.
The precursor to stand-up paddling is the outrigger canoe, several of which go out every day at Waikiki, packed with tourists. The men paddling these team canoes are the last of the Waikiki beach boys.
The Duke was one of the original boys - an unofficial group of watermen who shaped the last century of Hawaii's surf history. Their enthusiasm was responsible for the revival in the ancient sports of surfing and outrigger canoeing in the 1900s, and you can still find the same beach-boy friendliness at Waikiki in everyone from the guys renting boards on the sand to the sun-wrinkled old locals dishing out tips in the surf.
While Oahu island's Waikiki beach may have the greater claim to surfing history, the waves that the Hawaiian islands are best known for are the ones that batter Oahu's North Shore, which are created by storm-generated swells in the North Pacific.
At notorious breaks such as Pipeline, Sunset and Waimea Bay, professional surfers slug it out in enormous hollow tubes, trying to escape before the towering waters - up to 50ft high - crash down.
Many of these spots were considered unsurfable before the advent of shorter, lighter boards which could be manoeuvred quickly to avoid wipeout, but now even the juniors career in and out of the treacherous barrels.
Still, I wasn't tempted. If the yellow danger signs depicting surfers being chewed up by house-sized waves weren't enough, the stories I'd read of decent amateurs trapped and drowned under the reef left me with little desire to paddle out. But I couldn't go home without surfing the legendary North Shore, and, happily, help was at hand.
Hedemann's North Shore surf school is based at the Turtle Bay Hotel. Its surf coaches took us round the corner to a wave that, while still technically on the North Shore, was less likely to kill us.
Here, the waves were just a few feet high, breaking over a sharp reef a long paddle from shore. Smashing into that reef on a few wipeouts brought home how terrifying it would be to get pinned by something 10 times the size.
While Oahu is most associated with Hawaii's surf scene, the island of Hawaii - often called Big Island - claims its own surf pedigree. As its nickname suggests, it is the largest on the archipelago, but it's sparsely populated, with plenty of rugged scenery to explore.
Anthropologists cite Kealakekua Bay on the island's west coast - known as Kona - as the first place where a written record of surfing was made, by one of Captain Cook's crewmen. But breaks are trickier to find here than on Oahu. In fact, the best thing to do in the waters around the Big Island is to get under their surface - and you won't need fancy scuba gear to see fish all the colours of an Eighties rave. At Kahaluu Beach Park, a staggering multicoloured underwater world lies just 20 yards from the car park.
Succumbing to the Big Island's laid-back ambience, I abandoned any idea of surfing and hired a VW camper to explore. Setting off from the capital, Hilo, I headed north on a four-day circuit, starting at tranquil Spencer Beach Park.
Next was Kona's Hookena Beach Park - unspectacular, but a great starting point to explore snorkelling beaches such as Kahaluu. The best site was on the black sands of Punaluu Beach Park, where I woke to see enormous turtles sunbathing in volcanic rock pools just across from the van.
Before heading back to Hilo I drove inland to visit the spectacular Kilauea, the most active of the island's three live volcanoes. The lava wasn't flowing, but it was exciting enough to stand by its crater, taking in the strange atmosphere of impending doom, and catching a whiff of its intoxicating mix of fireworks and rotten eggs.
My last stop in Hawaii was the island of Kauai, whose most recent claim to fame is as the lush location for the film The Descendants. It's a curious meeting of Polynesia and Mid-West America; flat-roofed diners and shopping arcades straight out of the Fifties sit in front of enormous waterfalls cascading down the sides of a volcano.
Here the road hugs the sea and the water is full of figures bobbing on boards.
No wonder tiny Kauai is home to so many great surfers. Laird Hamilton, pioneer of tow-in surfing, where a jet ski propels the rider into implausibly huge waves, is the best known. He grew up here, and his dad, Bill, runs the board-rental shop at Hanalei Bay.
Hanalei is also home to professional surfer Bruce Irons and his brother Andy, a triple world-title winner. Andy suffered a fatal heart attack last year, and the trees by the beach are now a makeshift shrine to him.
Two beaches along from Hanalei Bay is "Tunnels", a surf spot where, in 2003, 13-year-old Bethany Hamilton had her arm bitten off by a tiger shark. Within three weeks she was back on a surfboard, and is now a professional - and the subject of a Hollywood film, Soul Surfer.
I headed to Bill Hamilton's shop for my final date with the Hawaiian surf, hired a longboard and paddled out into Hanalei Bay.
There will be some in Hawaii who wish The Duke had never shared their secret pleasure with the world. But as I caught another long, turquoise wave into the shore I could not help feeling very glad that he did.
- INDEPENDENT
