I was up at Arduaine, near Loch Melfort, on my annual holiday, and Andrew and Gerry Gilbert with their son Ian had come up from Hamilton for a day’s sail in Tarka, my Drascombe Lugger. The winds had been light for the previous two weeks, and the tides were neaps, so Gerry and Andrew suggested that we had a go at passing through the Little Corryvreckan, or Grey Dogs.

This is the narrow channel which separates the islands of Scarba and Lunga. It is divided into two channels by islets in the middle, and the broader channel is only 0.5 cables wide. The Clyde Cruising Club sailing directions suggest that, except at slack water, this passage should be avoided, as the tide runs like a mill race, reaching 8.5 kn springs, and 6.5 kn at neaps, with up to a metre difference in levels as the flow passes the islets.

There is 1 hour of slack water at neaps, which should allow plenty of time to get through, but the timing of the slack water is of great importance. HW was at 11.53, but the question in this case was — when does slack water start? Is it the hour before HW, or the hour after? Or does it straddle HW, with 30 minutes each side? We decided that if we reached the entrance to the channel by 11.00 hrs, one hour before HW, we would either go through on the last of the flood (which passes E to W), or on the slack.

The forecast was for light winds, force 2-3 from the NW, with no rain, so we left the jetty at Arduaine at 08.50. The wind was non-existent, and we motored SW past the new yacht haven at Craobh, heading past Shuna for the southern tip of Luing and the Ardluing buoy. From here the Grey Dogs is about two miles NW across the Sound of Luing. We reached the buoy a little early, and anchored for a while in the small bay on the SW tip of Luing. At 10.30 a slight NW breeze had arrived, so we sailed out, heading due west. After ten minutes the wind died, so the Yamaha 5 was started again and we motored across the sound to the Scarba shore, where we explored the jetty and bays below Kilmory Lodge, sighting three wild deer on the shore.

It was just 11.00 hrs when we reached the channel, and our timing must have been right, as we motored through with only the light W wind ruffling the water. Once through the channel we turned north and anchored in Camas a Mhor-Fhir Bay, on Lunga. The sand here was very white and very fine, so we put a stern anchor out, tied a line ashore, and had a lazy lunch in the sunshine.

We were now to the west of the chain of islands — Islay, Jura, Scarba, Lunga, Luing, Seil — which protect the relatively sheltered waters of the northern end of the Sound of Jura, Shuna Sound, Seil Sound and Loch Melfort from the westerly weather. The gaps between the islands in the chain all have considerable tidal flows, due to the fact that the tidal range to the west of the islands is around 4m, but to the east it is only between 1 and 2m. Our original plan had been to return by heading north up the Firth of Lorne against the ebb, either going through Cuan Sound or down through the Sound of Luing (both of which have 5 kn neap tides). However, after lunch, emboldened by the easy passage through the Grey Dogs, we decided to return by going south down the west side of Scarba and pass through the Gulf of Corryvreckan at LW slack.

The Gulf of Corryvreckan, which separates the islands of Scarba and Jura, is 1.5 miles long and about 0.5 miles wide at its narrowest point. It has a very uneven bottom, being on average 120m deep, but with a hole of 219m, and a high shelf 29m deep stretching out from the Scarba shore. The tide floods from east to west, and reaches 8.5 kn at springs, and 6.5 kn at neaps. The rough bottom and great volume of water flowing sets up large overfalls and standing waves, particularly where the 29m shelf reaches out from Scarba. At springs flood, the standing waves can rise to a height of 4m in calm weather, but may reach twice that height if there is a heavy westerly swell. The ebb produces less turbulence than the flood, but the sailing directions warn of huge overfalls in places.

As with the Little Corryvreckan, there is 1 hour slack at neaps, and LW was at 17.40, so the critical slack period could be from 16.40 to 17.40, or 17.40 to 18.40, or any intermediate 60 minutes. We did not want to be too late, as then the flood would be against us, and there could be no question of going through against the tide, so we decided to try to enter the gulf at 17.00 hrs, which seemed a reasonable compromise.

We left the anchorage on Lunga at about 13.15 hrs, and so had over 3 hours before entering the gulf. The wind was now westerly, 2-3, and we set sail and headed out NW. Some 2.5 miles ahead of us were the Garvellachs, or Isles of the Sea, where some of the earliest monastic remains in Scotland can be seen, and where St. Columba and St. Brendan are reputed to have stayed.

There was a drying rock on our heading, and we decided to avoid this by going about and heading south when we reached the transit of Fladda Light and the SW edge of Eilean Dubh Mor. We then had a very leisurely sail down to the bay on the west side of Scarba, called Port nan Urrachann. We anchored in 5m, put a line ashore, and then went ashore ourselves to explore a large cave and the smooth pebbles on the raised beach. This was a lonely spot, with the steep slopes of Scarba reaching up to 446m above us, and a slight swell coming in from the west. We were surprised by the lack of bird life here, and compared it with our trip two years ago around Garbh Eileach, one of the Isles of the Sea. The cliffs there were teeming with nesting birds, including a magnificent pair of golden eagles.

At 16.20 we decided to raise the 7.5 kg Bruce anchor and set off for the Corryvreckan. The wind was now SW and we motored out into quite short, steep seas, probably produced by the wind against tide. Once out from the bay we were able to bear south, set the sails, and have quite an invigorating sail, shipping a little water occasionally.

The sailing directions suggest two routes through the gulf when passing from west to east, the first being an approach made from mid-channel, and the second approaching from the SW with the tide race, mid-way between Eilean Mor and Buige Rock. We wanted to explore the anchorage in Bagh Gleann nam Muc Bay, on the NW corner of Jura, so chose to skirt round the mouth of the gulf and approach from the SW. We turned SE towards the gulf and could see quite a lot of white water to the north of Eilean Mor, where the sailing directions warn of huge overfalls.

As we rounded Eilean Mor and turned west, leaving Buige Rock to starboard, we saw more overfalls directly ahead. We started the engine to maintain steerage-way since the wind, now dead astern, was very light. When we reached the overfalls they turned out to be about 1.5m high, and Tarka rocked alarmingly, but we were soon through and into clearer, but still confused, water. Leaving Eilean Beag to port, we entered the bay. Looking back due north we could see a lot of white water and overfalls out in the gulf, on what was to be our exit from the bay, so we decided to anchor at the head of the bay, in firm sand, and wait to see what the tide did.

There was a large open motor boat anchored in the bay, with a charter party just embarking by dinghy to go home through the gulf. They must have arrived at the previous slack water for a day’s picnic on Jura, and were probably out from Crinan. After ten minutes the white water had subsided a bit, and the charter boat set off, so we raised the anchor and followed them out. There were still a lot of swirls and confused water, but we had a relatively clear run out into the middle of the gulf, where we turned to starboard and headed east on the last lap.

The wind was now a brisk NW, enabling us to have a fine sail out of the gulf, then NE past the Ardluing Buoy and the southern tips of Luing and Shuna. We had to motor the last three miles as the wind fell very light and the crew had to get back to Hamilton that night. We reached the mooring at Arduaine at 19.20 hrs, having been away 10.5 hrs and covered over 28 miles.

It was clear that we tried to enter Corryvreckan too early. If we had been 20 minutes later and entered at 17.20 hrs (20 minutes before LW), we would have avoided most of the overfalls. Remember that we entered only 20 minutes before slack water, that it was neaps, that the wind was with the ebb tide, and that there was only a very light swell out to the west — all favourable factors — and we still met considerable overfalls! It is certainly a place to be treated with great respect and a certain amount of awe.