Thursday, 24 Feb. We're driving to Manipouri, a small village on a lake in the southwest of the South Island. Manipouri is on the edge of the Fiordlands National Park, an enormous land and water mass that is almost completely without human habitation, and is now cherished and protected from any and all human development. The national park covers the coastline for several hundred kilometres, and quite a ways inland, encompassing fiords and subsidiary arms and inlets and lakes and islands. A map of the area is quite astonishing!

A relatively easy drive, we arrive in plenty of time for our midday ferry, the first stage to get us to the boat on which we will spend the night cruising around the fiord called Doubtful Sound. Captain Cook, who in the 1770's first charted the land of New Zealand from the sea, named this fiord "Doubtful" as he didn't think anyone could get a ship into and then out of the mouth of the fiord. Cap. Cook is a name that we hear and read about quite a bit as his travels to Australia and NZ were critical milestones in the history of European settlement of these two countries.

The ferry is one hour across Lake Manipouri, to the Power Station which was built controversially in the 1970s, largely underground, on the edge of the lake, in order to provide power to an aluminium plant many miles away on the south coast (google it if you're interested in the story!). At the far side of the lake, we are decanted from the ferry directly onto a large bus, which is to drive us up and over a mountain pass, to the base of the fiord. A road slightly wider than the bus, the driver is a pro and despite some hairy twists and turns, gets us to the boat in 35-40 minutes, despite stopping twice so we can photograph some lovely waterfalls. The drive left a few passengers a bit green about the gills. And the boat trip hasn't even started…

The ship sleeps 70 passengers, and we settle into our utilitarian twin cabin, which is basic but clean and neat. Everyone eats in one large room, filled with booths along the sides that allow us to look out through the windows, and long communal tables down the centre. They offer tea, coffee and muffins as we set off. We are free to wander about most of the ship, there is an enclosed observation deck as well as open areas. We are also free to hang out on the Captain's Bridge, which we loved as it had the best views and was warm. We will be on the ship until about 10 am tomorrow. There is a naturalist on board who periodically turns on her mike and enlightens us about what we are seeing—from the trees and plants that grow on the near-90 degree slopes right down to the water, to the creatures flying overhead and swimming beneath us. She is a fount of information (and also multi-talented—in the morning, Robin takes an early stroll on deck and she is singlehandedly pulling up the anchor—it's all mechanised, but still..) The scenery is quite extraordinary. We are travelling down a relatively narrow water passage and the walls of the fiord are almost vertical yet covered with trees and greenery, with occasional dramatic waterfalls, wide, thin, tumbling over outcrops of rock or falling down long stretches. This area gets something like 6 meters of rain (230 plus inches) a year, so it is very green. But the trees don't have deep roots, they are anchored to the steep granite hillsides by a network of interlocking roots of many plants. Quite an extraordinary sight when you know how it grows.

The crew are very jolly, make us feel like we're at overnight camp. To start with, there's some messing about in boats-either on tenders which take some of us up close to shore to see the extraordinary greenery up close, or kayaks for the more adventurous. And for the really brave/silly folks, there was a swim off the boat in the 61F/16C water. Once everyone was safely back onboard, it was soup all around. The feeding operation is military in its efficiency, but the crew were also friendly and very helpful. Before the sun had set, we reached the mouth of the fiord, and headed over to a group of tiny islets, rocks really, on which we were able to observe a large group of fur seals, both adults and babies. After that excitement, we went inside for dinner. And considering the tiny kitchen on board, and the number they were feeding, it wasn't bad. No Michelin stars, but edible, good selection. There were a piano and board games for the younger set, and a slide show after dinner on offer as well.

Next morning, reveille was early with the smell of bacon wafting through the corridors to encourage the lazy. After breakfast we had one last diversion into a quiet inlet off the main fiord. Here they did a wonderful thing. They announced they were going to turn off the ship's engines, and they asked everyone to be absolutely still—don't move, don't speak, don't take photos. Just stand and listen. And we all complied. Robin and I were standing on the forward open deck, and for a minute or so after the engines completely cut out, there was pure silence except for the waterfalls cascading down the sides of the inlet, and then gradually birds singing became audible—pure music which we hadn't been able to appreciate over the engines—and nothing else. It's virtually impossible in our normal lives to escape entirely the sounds of human habitation, so this was a wonderful, magical experience.

When we had been still for some minutes, they revved up the engines and it was back to the real world. We then reversed our previous day's journey, with the bus ride up and back over the pass, then the ferry ride back to Manipouri.