Most of what I write is set in a real world, in places I know and love. The characters are made up, of course, and some, not all, of the boats. Serendipity is an imaginary ideal yacht, but my younger son Steve acquired a yacht in need of some TLC that has certain characteristics in common with Serendipity. Birubi is forty-two feet long, steel hulled with a double chine, and ketch-rigged. Built in 1967 in Australia, to the design of a former Naval officer, she is beautiful and sails very well.

So when Steve rang me to say he was sailing Birubi from Levington (Suffolk Yacht Harbour) to Maldon, where he was going to do certain work on her, and would I like to go along, I didn't have to think too long before saying yes. The fact I would have to get to Levington (not the most accessible place in the world unless you want to leave your car there) and we would be leaving at two in the morning to catch the tide ... minor detail. That Birubi had a foul bottom, despite recent anti-fouling and would be sluggish ... and the wind was not ideal ... again, minor detail. Steve, like Captain Quinton, dislikes engines, and is determined to manage without.

So, having got out of bed at six-thirty, and spent an hour for a customer, moving furniture and covering it with dust-sheets in preparation for a contractor to do some damp-proofing work, I had an early lunch, threw some stuff in the back of the car and set off. I was to be collected from Maldon by a friend of Steve's, who would be helping us, at about nine-thirty.

There was no great rush, but for some reason I found I was cruising at seventy instead of my usual, economical, sixty. A break for coffee at Peterborough, where I got a warning of delays near Huntingdon ... but there wasn't much I could do to avoid that, so I just kept going. As it turned out, I did get held up in stop/start traffic, but that cleared soon enough and then I was getting along nicely: A14, then M11 past Cambridge. The interchange for the A120, and not long after that, I was pulling in to the rest area and buying a bacon sandwich, Danish, and more coffee.

I was back on the road several minutes when Steve called and I had to find a lay-by to pull off to ring him back. Would I get some perishable supplies for the boat? Not a problem – solved by a call in at Tesco as I entered Maldon.

I had a couple of hours to kill, and spent them at my older son's flat with my granddaughters until it was their bed-time. Steve turned up on time, with Phil who was going with us. Phil's mother would drive us the fifty miles to Levington. Three men, with their dunnage, in a Peugeot 107, plus Phil's mother driving. It was tight.

It was only at Levington I was told Birubi was on a swinging mooring on the other side of the river. It meant using the dinghy; a degree of ingenuity was required to get all three of us and our gear in. The dinghy had clearly been designed to be sailed and did not row well. Steve's aversion to internal combustion engines extended to his tender. I'd have preferred a little more free-board, but fortunately the water was smooth. In case you were wondering, it was not practical to take Birubi into the marina

The Orwell is quite a wide river and the flood was well under way as Steve laboured to get us across. We were aboard – I was surprised how easy it was to find her in the gloom – a little after eleven, and in our bunks just after midnight with the intention of getting up at two to catch the start of the ebb. I didn't really expect to sleep, but was woken at three by Steve moving about; he'd overslept, but it didn't make much difference as there was no wind.

None the less, we went about preparing to get under way. I was given the task of bending on the Genoa above the number two stay-sail, the latter was bundled in a sail-bag and lashed to the rail. I wondered what we'd do if the lack of wind continued, but a breath of wind teased us, then strengthened. We got under way at three fifty-seven with me (me!) at the tiller. Yes – tiller. Steve had disconnected the wheel at some point and he preferred using the tiller which was originally intended to be for emergency use.

Ahead of us the lights of Felixstowe Docks blazed, making it sometimes difficult to identify the lights of the buoys marking the fairway. It seemed to take a long time to get to the beginning of the container terminal wharf with its great cranes. A large Maersk Lines ship was unloading at the north end. I concentrated on trying to keep buoys in sight as they flashed and went dark for several seconds at a time. I was vaguely aware of being cold, and regretted not putting more layers on before we started.

Birubi was moving quite nicely at perhaps two or three knots through the water, which was also flowing at perhaps another knot, as we passed Shotley Point, the Shotley Spit cardinal buoy flashing away. Birubi was, of course, fighting to cross the current from the Stour, which led to the first heart-stopping moment. The wind dropped just as we were passing upstream of the buoy marking the entrance to the Stour. We cleared it by barely ten feet ... not nearly enough for my happiness. But clear it we did, and then we were heading to pass the west cardinal buoy marking the shallows off Harwich. At the North Shelf buoy, we were able to head south.

Steve and Phil dropped the mainsail, lashed it to the boom, and used the boom as a crane, to hoist the dinghy aboard – the mainsheet to the transom and the main halyard to the bows of the little boat. I was fascinated. Almost before I knew what they were doing, the boat was aboard and upside down under the boom. Very neat. Except that it partly blocked the view forward.

Steve was able to identify the Landguard cardinal and, to my surprise, the Pye End buoy, with its white light flashing. Of course, we weren't going to enter the Walton channel, or we wouldn't have been able to see it. I was supposed to be heading for the Stone Banks buoy, but I couldn't see it without craning around. However, I could see Orion, which was perfectly placed to be our guide as we headed out. I'd heard of steering by the stars, but never done it before.

Steve relieved me at the helm so that I could go below and get some more insulation. Overtrousers – why do they make them so you have to undress to go to the toilet? – sea-boot socks and wellingtons, water-proof jacket over the fleece, stocking hat. That was better...

I returned to the cockpit. Before taking the tiller again, I could see the Stone Banks buoy, or rather its flashing red light, and beyond it the green light of the Medusa, a further two miles. I asked about it.