After a week sailing the South West coast in Snowfire, our Loch Broom Post Boat, we decided we'd end the holiday with a night pilotage exercise. The inshore waters forecast predicted reasonable conditions for a sail from Falmouth Yacht Haven to the Helford River and back to an anchorage at Channals Creek, at the top of the Carrick Roads. Tidal streams would be fair for the outward leg of the voyage and against us on the way back, though not too strong, given that we expected to be able to sail at three knots or slightly more.

We left Falmouth in light winds and under engine. We had a point just to seaward of August Rock, about 2/3 the way to the Helford River, entered into the hand-held GPS as a waypoint, but visibility was so good that we were easily able to use visual pilotage across the bay. When we were abeam of August Rock, the breeze kicked in and we were able to sail up the Helford river.

We picked up a visitors mooring and waited for sunset before starting the return journey. As the sun disappeared behind the steeply wooded banks of the river and the lights began to come on in houses and pubs, we hoisted full main and No.1 jib and sailed out of the anchorage. As well as the big lantern that we carry to meet the requirements of the IRPCS, we also had a set of 'emergency navigation lights.' These are small lights that clip onto mountings on the garboard strake. They're intended as an emergency set of lights for yachts but make good primary navigation lights for a small keelboat, even though they set a bit low to be seen easily.

Anyway, we lit them now and their coloured lights gave a reassuring glow to the waves just alongside. By the time we reached August Rock, full darkness had fallen and with the wind continuing to rise we decided to put a reef in the main. Gaff-rigged boats don't sail as close to the wind as bermudans, and don't sail very fast on what passes for close-hauled even then. As it was, we found ourselves sailing a very close reach against a spring tide and whilst we were making good progress, we had to make several tacks to weather a gas tanker that was anchored in the bay. From this point we set a course towards the light house on St Anthony Head that was flashing its distinctive pattern ahead of us, and towards a clearance waypoint between the St Anthony lighthouse and Black Rock cardinal marker that we'd pre-programmed into the GPS. This ensured that we'd know when we were safely beyond the Black Rock cluster of navigation hazards.

We sailed on in a rising wind until the light on the Black Rock cardinal buoy was abaft the beam and the clearance waypoint showed due north. At this point, the only other vessel we saw moving that night, a yacht, passed ahead of us into the Carrick Roads. The tide was now stonking out of the estuary and we had the wind in our teeth. We could only make the slowest of headway by beating so we handed the jib and motor-sailed into the estuary. We'd prepared a pilotage plan before we set out and we now put it to good use. It held a complete list of each buoy we'd meet, its hand and its light pattern, all the way from the Wolf Rock cardinal to the Turnaware Bar buoy just before Channals Creek. We were able to read the list and the chart of the estuary that we carried in a waterproof case, by the light of head torches with red lenses. One lesson we learned was that you need to write your notes in very large letters as it's not easy reading a pencilled list by red torchlight through a wet plastic chart case.

We made our way up the estuary from buoy to buoy, carefully identifying each one by its light characteristics. With our shallow draught, we could have taken short cuts across the estuary, cutting out certain buoys, but we decided against this as it might have been possible in the dark to mistake one buoy for another if they were not approached in sequence and ticked off on the pilotage plan as we passed them. In fact this is almost what happened but we were on the lookout for the large, yellow ship's mooring buoy in the middle of the Carrick Roads. We spotted it at the point that we expected to see it according to the pilotage plan - but on the wrong bearing. This alerted us to the fact that we'd mistaken one port-hand buoy's flash pattern for the one after it. This reinforced the fact that it's easy to see what you want to see rather than what's really in front of you, when piloting a vessel in the dark. This time it was all the easier because a heavy rain had started, bringing visibility down to a few hundred yards. The lesson is - time the flashes with a watch, don't guess.

When we reached the St Just port-hand buoy, we were almost stumped. We knew the light pattern of the next buoy in sequence, a starboard-hand, but before us was a wall of darkness and teeming rain. No buoy. Our initial assumption was that its light was out, so out came the chart for a quick check of what bearing we needed to be on. Having made a wide turn onto this heading we picked up the light of the next buoy that was very far off and almost obscured by the curtain of rain we were motoring through. We'd been pointing towards St Just and not up the estuary as we'd thought in the darkness. This reminded us that a pilotage plan should contain bearings of every buoy from its predecessor and not just the ones that you think are going to be difficult customers. That way you can always check you really have got the right next buoy, or that you know exactly where to look for it.

It was at this point that the lightning started. Sheet lightning at first, then multiple bolts making land strikes. We realised that our mast was the highest point in the middle of a waste of water. We also realised that even when we'd anchored, we'd still be the highest point on the water and we kept our nerve. In fact, by this point we were exhilarated and high on adrenalin. Our senses were sharpened and we felt like we were living on a higher level than the ordinary. It was hard to know how close to each buoy we were approaching and the lightning flashes temporarily destroyed our night vision each time they went off. We had to search for the hull of each buoy with the big white lantern each time we felt we were close to one. Sometimes several lightning bolts would flicker to earth just as we approached a buoy, leaving our retinas imprinted with nothing more than the pattern of the wooded shore and a silhouette of the buoy we were looking for, a few yards ahead. We were warm and dry in our oilskins but were still glad to see the last buoy in sequence flashing its green light ahead.

The pilotage plan showed the bearing and distance to the point we'd chosen at the outset as best to drop anchor at. It gave shelter from the wind direction we'd expected and from any waves it was likely to set up. It was far enough up the creek for us to be the only boat shoal-draughted enough to reach it and it had an excellent marker – a white-painted rowing boat that we'd seen on previous visits always moored in the same position just adjacent to it but outside our projected swinging circle. Sure enough, we picked out the rowing boat in the beam of the lantern and rounded to just at the spot we'd chosen. It was close to low water by now but we veered out enough scope of chain and warp after our bower anchor to be sure of holding at the next high water.

It was 0105 as we lit our riding light and we rigged our boat cover. The rain was still pelting down and the lightning was still lighting up the landscape around us. Once the cover was rigged, it didn't take very long to pump the bilges out and dry the inside of the boat. We had to seal the boat cover around the mast with a piece of wetsuit neoprene to keep the streaming rain out. After that we just rolled out the self-inflating mattress and got into our sleeping bags. There was no question of taking transits to make sure we weren't dragging our anchor - we couldn't see anything anyway. We just had to veer out enough warp and trust to the anchor. As we lay in our sleeping bags we could see the lightning flashes through the boat cover. Through the boat cover? We had our eyes fast shut and we could still see them through the boat cover and our eyelids. There was no getting to sleep amidst the flashes, the thunder and the rain that beat like a drum on the boat.

But sleep we eventually did and awoke the next morning to find ourselves in a newly-washed world, inshore of a group of yachts that we'd managed to thread our way between in the dark, to find our right anchorage. It was time to sail to Mylor to recover the boat and go home. But what a sail to end the voyage on - a real high point that had sharpened up our night pilotage skills.