There's nothing the matter with the day. It's blue and beautiful after rain. The lake sparkles and ruffles in the breeze: white sheep graze on a green hill: thin tree trunks shimmer reflections in the water: the oars drip circles.

Then it's my turn to row, and I can't do it. It requires a number of things I don't have. Coordination. Upper arm strength. A sense of kinaesthetic rhythm. An ability to follow oral instructions. A willingness to try something that I'm not good at.

The oars are in my hands. There are three simple moves I need to make to propel myself in a straight line back to lunch. Pull my arms back, gripping the oars close together. Dip both oars in the water at the same time to the same depth with the same strength. Lift the oars out of the water and repeat.

We make up a song to help me achieve this. It doesn't work. My instructor is uncomprehending. He's been rowing for 60 years, since he was seven. He's rowed seven hour stints up the Murray. He tackles a number of different instructive strategies. Finally, he turns his back to me, dangles his feet into the water, and says “It's your job to get us back for lunch.”

I pick a cluster of trees on the green hill, on the sky line above the white sheep, to monitor my direction. I mutter mantras to myself. I zag and zig down the empty lake, the trees relocating themselves giddily from far left to far right. Sometimes I pull on the right oar (or the left oar) to get my trees back in line: sometimes I pull on the wrong one. I try rowing first with one oar, then with the other. I zig and zag. I feel tears of failure. The wind is behind me so I make progress.

The boat looks innocent and idyllic, sitting on the water without its oars. To me it's become demonic. Is all I need to master rowing practice? I hope so. Over the years, I've had four children, clambered down very steep hills into rainforest, jumped over rocks where the surf roils, camped in places way off the beaten track, all in the company of my rowing instructor. Has he finally set a challenge I can't meet?

This week he will leave the boat in the creek at Potato Point for a day so I can practise by myself. My mind is generating excuses. The creek looks very shallow: there won't be enough clearance. Maybe it's the school cross country: they marshall at the launching point. Oops! I forgot: I have to go to the dentist.

My mind hasn't been this excuse-active since I had to give a talk on the Continental System to my history class in 1954.