I awake with a start. The loud lapping of the waves against the side of the boat can only mean one thing. They are coming from the beam rather than the bow as they would if we were swinging freely. I quickly dress and go on deck. The wind is coming from the east, and all the other boats next to us are aligned east west except us, aligned north south. I switch on the depth sounder. It reads zero. We are grounded.

Grounded off Green Island in Poole harbour.

We are in Poole Harbour. Rather than stay in a marina, we had decided on peace and solitude and had taken the left turn after entering the harbour and followed the narrow South Deep channel around the south of Brownsea Island, and had found a nice place to anchor with a few other boats  just on the edge of the channel near Green Island. I had done my tidal calculations and had estimated that we would have 40 cm under the keel at low tide at 0430 in the morning. Not a lot, but enough. I had gambled on the wind staying in the east as was forecast, which would have kept us aligned at the edge of the channel, but at some time during the night either the wind or the current had changed and we had swung round to where it was shallower. Then at low tide, the keel had settled gently into the mud. No matter, it is a rising tide. I make a cup of tea and sit down to wait.

We had arrived in Poole the night before. We had left our paradise on the Beaulieu River in the morning, and had caught the start of the west flowing current down towards the Needles. Before long we were passing Yarmouth to our left, then Keyhaven to our right, each with their respective fortifications guarding the entrance to the Solent, Fort Albert and Hurst Castle. At some point we had noticed a tall ship following us and hoped that she would catch us up so we could get a good view of her.

Tall ship passing us near the Needles.

We had passed the Needles, chalk stacks extending out from the western end of the Isle of Wight. To our right had been the dangerous pebble reef called the Shingles, so we had steered a route between two buoys that took us safely through the two hazards.

Passing the Needles off the Isle of Wight.

From there, we had set a course directly west to Poole. The wind had strengthened to 10-12 knots and we had whizzed along, helped by a favourable current which had taken us in a looping arch northwards then southwards across Christchurch Bay and Poole Bay. A couple of hours later, we were approaching Old Harry Rocks at the bottom end of Studland Bay, more chalk stacks that are the same stratum as the Needles. The sails in, we had had a brief stop for a cuppa in Studland Bay, then had pushed on up the dredged channel into Poole harbour, then to our anchoring spot.

Old Harry Rocks, Studland Bay, near Poole.

There is a slight tremor and Ruby Tuesday detaches herself from the mud below and begins to swing freely, out in the deeper water and aligning herself with the other boats. The depth sounder suddenly reads 2 metres. We are free again!