Five minutes into our paddle down Dalmatia's Krka river, my father began to shift uncomfortably at the front of our double kayak. By the time we stopped for a cooling dip he proclaimed himself to be in agony. Our guide, Davor, tried to reconfigure his seating arrangements, exhorting him to stretch his legs out fully in front of him. "Impossible," snapped my father. "Why?" Davor asked. "Because," I pointed out uncharitably, "he is old."
As an only child of parents who separated when I was young, I was used to holidaying alone with my father, Oliver (and, separately, my mother). Some of my fondest travel memories are of car journeys to the Isle of Wight, where he would amuse me with fiendish quizzes based largely on the attractions of Blackgang Chine, or, if it was hot, allow me to cool him down using a loaded water pistol.
But it had been many years since our last adventure when he suggested I accompany him to central France. There, on the roads of the Auvergne's Allier département – though minus the water pistols – the decades that had passed had changed nothing. It was also there, on the Gorges de Chouvigny and lazy stretches of the Sioule, that I introduced him to kayaking. He loved it, and when we came to discuss a trip the following year, lobbied for more.
And so we found ourselves in Croatia – him aged 69 and me 31. The country's sea-kayaking, around the rugged islands of the Adriatic, is much celebrated. But its rivers, winding through canyons, forests and peaceful flower-filled banks, offer equal rewards for anyone seeking less discovered territory. And besides, my dad didn't like the idea of the depth of the sea. A river trip seemed ideal.
Yet after a day battling the currents of the Krka, both of us were beginning to wonder if we'd been overambitious. My father insisted on covering half his body with ibuprofen gel, and after taking most of the paddling strain I found my fingers so stiff I could barely tap out a text message home. The prospect of white-water rafting the next day concerned me: was it really the right environment for a near-septuagenarian?
At the edge of the Cetina Gorge, Davor's colleague Ilija explained how he would direct our paddling in the grade three waters (demanding good paddling skills). When he shouted left, those on the left must paddle, and vice versa. When he shouted "strongly forward", we must go hell for leather. No one, he warned gravely, must stop paddling when they were supposed to be paddling. I informed my father – not the strongest swimmer – that if there was the slightest sign he was going to exit the raft, I would immediately stop paddling and devote my attentions to keeping him on board.
Soon we were bobbing downstream towards the gurgling of white water. We paddled left, right, back and strongly forward as instructed and gasps of trepidation gave way to joyous shrieks as our raft slithered and twisted its way through the rocky corridor. Suddenly we were back on still water, waving our paddles with glee as the mingled scents of mud, moss and pine rose from the riverbank and an egret stalked through the shallows. My father was still in his seat, grinning with delight.
Further down the river we disembarked to allow Davor and Ilija to navigate the rafts through higher-grade rapids. We refilled our water bottles from a freshwater stream and leapt from huge rocks into the minty-coloured depths of the gorge.
Back at Skradin, our riverside base, our group recounted the day's dramas over soup and grilled fish, then strolled through the car-free streets in search of ice-cream. At the marina, where by day holidaying Croatian families bathed and cap-clad elderly men nattered under the trees, champagne flutes clinked aboard gleaming superboats.
For bigger city thrills, Split, with its glittering harbour-side strip backed by the emperor Diocletian's Palace, is an hour's drive south-east, and Unesco-listed Trogir, an island of medieval streets and squares, seafood platters and pizzas, is closer still.
In the other direction is Zadar, rougher round the edges and the proud owner of one the world's few sea organs, hidden beneath a set of white stone steps on the quayside. As the waves splosh against them the movement pushes air through 35 tuned tubes, creating a series of random, undulating harmonies. The children in our group soon hurled themselves into the water, and despite a lack of swimwear the temptation to join them proved irresistible. Bobbing around in my underwear to the organ's breathy hum, I had one of the best swims of my life.
Our final day was to be white-water kayaking. On arrival at the Zrmanja river, after a drive passing shelled buildings remaining from the homeland wars, we were handed a plastic barrel to be strapped to the kayak. It was designed to keep our belongings dry; it also provided a back rest for my father that meant he could finally paddle pain-free.
As we slid through flat green water and then over easy rapids, the foothills of the Velebit national park rose to our right. We slipped through a secret opening in some reeds and headed upstream on the gentle Krupa before pulling up at a small meadow.
"We will walk for 10 minutes and then we will get to a very beautiful place," Davor told us. We stumbled along a rocky path clutching our barrels, bent under a natural stone arch and found ourselves at a cool, deep pool with a waterfall spilling from the river above. Heading back down the Zrmanja we navigated ever-trickier white water.
Then came the moment I had dreaded all along. As we swung neatly round a jutting rock and shot through the frothing waters, our kayak lurched down on the left-hand side and I watched my father topple into the fast-moving river. I barked at him to swim to the bank and grab a tree root; I feared he would emerge from this new ordeal not just injured but with his confidence severely shaken.
I need not have worried. As I checked for bruises, his grin was wider than ever. The verdict? "Thrilling."
