It's the third morning of our week on North Stradbroke Island when we go for a stand up paddle-boarding lesson.
For most of us, including my oldest mate Hugh, his teenage daughter, her friend and his son, this is doddle.
Even my seven year-old Mila manages some time standing on the board before settling down on her knees and propelling herself expertly through the ocean, off Adam's Beach.
Meanwhile, my chilled five-year-old, Freya, simply sits cross-legged on instructor Chris Semple's board as he chauffeurs her about.
I, on the other hand, display all the balance and technical skill of a one-legged donkey on a trapeze.
Time after time, I wobble to my feet and dig my paddle into the water only to plunge face first into the drink. When I do get going, a strong headwind blows me to a standstill, like Marcel Marceau up against an invisible wall, or shoves me back toward the coastal mangroves. I end up with a nose full of ocean, seaweed in my ears and upper arms throbbing as if I've been holding up the world.
This visit to "Straddie", off Queensland's coast just south-east of Brisbane, isn't just a rare opportunity to catch up with my oldest friend. It's also a chance to create some old-fashioned holiday memories for my girls: long days at the beach with little to do but create sandcastles, dig moats and swim for hours in the Pacific.
It also underlines the value of an extended "family", the girls connecting with "cousins", ranging in age from nine to 17 and "aunts" and "uncles".
From day one, at the expansive holiday rental we're sharing at the island's most popular tourist village, Point Lookout, my girls make a beeline for their teenage "cousin" Hannah and her friend, Jana. I'm consigned to book reading and Tai-Chi.
Not that anybody in our group, which expands to 14 at times, is here to laze about. Apart from exposing the kids to many tendrils of the wider family, the other essential for a stress-free holiday is exhausting them. Let the kids throw themselves into nature at full pelt so that, when it comes to bedtime, there are nothing but yawns.
From day two, when we make the 5.2 kilometre return trek to Blue Lake, this becomes the carefully executed plan. Inland from the long coastal beaches on Straddie's eastern shore, the walk to the indigo-coloured lake works its magic beautifully, especially when combined with a swim in its cool, sweet waters.
But, in terms of wear-out factor, this has nothing on the paddle boarding tour – for me at least.
It's serendipitous that a) I have a massage booked for the afternoon and b) the three teenagers have offered to babysit while the adults swan off to dinner at Look Beach Cafe. If only my aching arms didn't find it so difficult lifting a fork, the salt and pepper squid and the prawn and scallop pasta would be an undiluted pleasure.
Each morning begins with Hugh and I doing Tai-Chi on the deck, mimicking the flowing movements of a tiny Chinese instructress on a DVD, with coastal views in the background and chirping birds all around. This serves several functions: relief from middle-aged stiffness and some peace and serenity, and it allows the kids to laugh at their dads. A lot.
But being the butt of jokes is a small price to pay for a memorable family holiday.
One afternoon I manage to drag the girls away from their teenage idols to return to the scene of my paddle-boarding humiliation, at Adam's Beach, and find it transformed, the mangroves and mudflats exposed by a low tide and convulsing with movement. Thousands upon thousands of soldier crabs are massing and fanning out like migrating wildebeest as we approach, before vanishing into shallow muddy pools when we get too close. The girls are beside themselves at this natural phenomenon and don't want to leave.
Nor, when we go looking for koalas at Straddie's main town, Dunwich, with Romane Cristescu, a French/Romanian wildlife carer, do they want to say goodbye to the marsupials we find among the gum trees.
North Stradbroke has the largest, healthiest population of wild koalas in South-East Queensland, the creatures having benefited from the island's relative isolation and low-density housing.
"Straddie is like South Australia's Kangaroo Island," says Cristescu in a blancmange of French and Strine, "for the nature and its wildlife."
"Apart from the koalas," she says, "we have squirrel gliders, sugar gliders and feather gliders and agile and golden swamp wallabies, too."
Too soon, it's our last afternoon on Straddie and our greatest challenge, sandboarding on the blow behind Point Lookout, with Straddie Adventures.
The descent seems akin to the sheer, powdery face of K2. So I'm not surprised when, after the introductory lesson, Mila doesn't think she can do it. But with a little gentle encouragement from her extended family, and a few smooth runs from lower down the slope, she's soon gliding down the precipice, a beaming smile on her face. As isfive-year-old Freya. As am I.
I manage several slaloms down the piste without too huge a fall. It's all going so well that middle-aged male hubris sets in and I accept an invitation to a race from Hugh's teenage son.
I'm still stuttering at the top when Adam reaches the bottom, but I finally gather speed, eager to show my daughters my newfound talent. Half-way down I know what's coming, but can't prevent it. Then it happens. History's most graceless stack and perhaps its most cartoon-like face-plant, too.
Every exposed orifice is rammed with sand as my legs flap behind like the tail of a leaping salmon.
I'm still snorting granules out of my nostrils at dinner at Fishes At the Point restaurant and, as if to underline the importance of our extended family, everybody, from my five-year-old to my oldest mate, is still laughing at my misfortune.
Some car-hire companies have insurance issues with vehicles being taken over to Stradbroke but Cleveland-based Betta car hire includes insurance cover for the island. The company also picks up and returns customers to Brisbane airport as part of the booking. See bettacarhire.com.au
Stradbroke ferries has regular car services to Dunwich on the island, journey time just under an hour. See stradbrokeferries.com.au
STAYING AND EATING THERE
Discover Stradbroke has a range of holiday houses available on the island. See discoverstradbroke.com.au
Look Beach Bar Cafe, Point Lookout, is open Wednesday-Sunday, 8am-2.30pm, 6pm to late. See beachbarcafe.com
Fishes At the Point Cafe is open seven days, 8am-8pm, until late Friday and Saturday. See fishesatthepoint.com.au
Straddie Stand Up Paddle offers 90-minute lessons for $50 a person or priced according to numbers for groups. See straddiestanduppaddle.com/
Straddie Adventures has two-hour sandboarding tours from $30 a person. See straddieadventures.com.au
The author and his daughters travelled courtesy of Tourism and Events Queensland and Visit Brisbane.
FIVE MORE THINGS TO DO ON STRADBROKE ISLAND
Dive or snorkel among rays and turtles off Point Lookout with local dive shop, Manta Lodge and scuba centre. Snorkelling tours cost from $60 per person, dive trips from $131. See mantalodge.com.au.
Do a half-day four-wheel-drive tour of the island with local guide Dave Thelander, taking in Stradbroke's northern section and driving along part of the 32-kilometre long Main Beach. Adults $60, children $35. See straddiekingfishertours.com.au.
Visit North Stradbroke Historical Museum at Dunwich, which has exhibits on the island's indigenous and colonial history and a sperm whale skeleton. Opens Tuesday-Saturday, 10am-2pm, Sunday 11am-3pm. See stradbrokemuseum.com.au.
Go sea kayaking off Cylinder Beach, hopping out of the kayaks to snorkel at Shag Rock. Adults $50, children $40. See straddieadventures.com.au
Take the 1.2-kilometre North Gorge walk at Point Lookout, which horseshoes around the narrow inlet in the headland, looking out for dolphins, turtles and rays in the water below.