Doubtful Sound
Doubtful Sound was named Doubtful Harbour by Captain Cook, who did not enter the inlet as he was uncertain whether it was navigable under sail. It was later named Doubtful Sound by whalers and sealers.
Access to the sound is either by sea, or by the Wilmot Pass road from the Manapouri Power Station. The Wilmot Pass is the most expensive road ever constructed.
There are three distinct arms to the sound, which is the site of several large waterfalls, notably Helena Falls at Deep Cove, and the Browne Falls which have a fall of nearly 600 metres.
Doubtful Sound is unusual in that it contains two distinct layers of water that do not mix. The top few meters is fresh water, fed from the high inflows from the surrounding mountains. Below this is a layer of cold, heavy, saline water from the sea.
The difference in Refractive index between these two layers makes it difficult for light to penetrate. Thus, many deep-sea species, such as Black coral will grow in the comparatively shallow depths of the Sound.
The waterways are known for dolphin sightings and it's common for dolphins to chase tour boats.
The are lots of ways of seeing the fjord including overnight kayaking, overnight sailing and various day cruises. We'd recommend the little boat of Fiordland Explorer Charters for a day cruise and, if you can afford it, the overnight cruise from Real Journeys (this includes an hour kayaking on the Sound if the weather is fine!!).
