Key Points:

The Waihou River runs from the south of the Firth of Thames into the hills, valleys and flat lands of the lower Coromandel, eastern Waikato and Hauraki Plains.

It is passed over by thousands each day in their vehicles, either just out of Paeroa on State Highway 2 or on the infamous Kopu Bridge. It is also a bustling waterway, with a fascinating history and is well worth a visit by pleasure boat owners looking for a change from their cruises on the sea.

Those wanting to explore the Waihou have a number of options. They can launch close to home and then join the river at its entrance, close to the township of Thames. Alternatively, there are several launching ramps along the river: at Paeroa, Turua (about halfway between Paeroa and the river mouth) and Te Aroha.

If coming from Auckland, it is best to cruise towards the southern edge of the Firth of Thames. When approaching Thames, look for a beacon and then, just beyond, a series of red buoys. Be sure to keep the beacon to starboard, especially at low tide, as oyster beds await the unwary.

Follow the red buoys (they do not have to be kept to port as long as they are close by) and the mouth of the river begins where they end.

It is best to keep to the western or right hand side of the river for the first few miles (probably until Turua) as there is good depth there (the eastern side is shallower with mud banks in places) especially at lower tides.

As always when exploring unknown waters, it is best to choose a big tide and head up as early as possible on the rising tide.

The river has good depth for even quite large boats from half tide or more and there is a bit more leeway for smaller vessels. It also pays to keep a good lookout for logs and other floating debris, especially after heavy rain.

The first major "sight" is the historic Kopu Bridge. Still able to open for bigger ships, the bridge is a legacy of the days when the river was the main means of transport for the whole Hauraki Plains and surrounding districts. Coal, timber, flax and gold were all transported down to the sea while people, supplies and mail passed on their way up river.

From Kopu to Turua, the river is wide and quite muddy but no less beautiful for that. To the east, the majestic Coromandel ranges and their foothills dominate; to the left, the plains. On both sides (and for a considerable distance) mai mais abound, varied in their design and level of upkeep. One imagines, therefore, that this river might not be such a welcoming place on the first weekend in May.

South of Turua, it is best to stick to the middle of the river with a slight bias to the outside of any turns. After a pronounced left-hand bend in the river, an island appears. Take the left-hand fork and then pay particular attention, as this is trickiest part of the journey; stick to the right-hand side for about 50m or so.

Once past this, it is pretty straightforward until Paeroa. There is just the one other fork but it is pretty obvious that the Waihou is the river that flows to the right.

Just past this fork is one of the most interesting historical sights: the spot where Cook reached in his exploration of the river on November 20, 1769. A small jetty marks the spot and a short walk across a farm paddock leads up to a monument that marks the spot.

Cook initially named the river the Thames and it remained that way until 1928 when it was surveyed and renamed the Waihou. All along the river are reminders of its past: old flax mills and other signs of historic industry; old fresh water pumps for dairy factories and the like.

There is also a profusion of wild birds: ducks, swans and shags are everywhere.

Past the monument, the water gets clearer as the fresh water from the surrounding hills gradually replaces the brackish water of the Firth. Mt Te Aroha appears in the distance and seems surprisingly far away, especially as the river flows strongly all the way there and even beyond.

At Paeroa, just beyond the bridge, a small waterway leads to the back of the Historical Maritime Park. From here, two commercial boats still ply the river, taking passengers for cruises. One of these, the Otunui, is a 100-year-old paddle steamer, lovingly restored.

This little tributary (aptly called the Dead End) is well worth exploring as a number of old naval and other vessels are moored in this beautiful, meandering waterway.

Further on, there is a more substantial fork to the left. This is the Ohinemuri River, which flows through Paeroa and the Karangahake Gorge to Waikino and Waihi.

These days, it is still navigable all the way to the giant L&P bottle on the way out of town but there are no wharves or beaches for easy access ashore. It also pays to watch out for a big sand bank jutting out on the inside of a big right-hand turn.

Beyond Paeroa, the Waihou becomes more winding but more interesting, too, as the banks close in.

Now the skipper really needs to pay attention as sand banks on inside corners, partly submerged logs and willows trying to take over the river all have to be avoided.

However, with care, the right tide and good planning the Waihou will grant access all the way through to Stanley's Landing (about halfway between Te Aroha and Matamata).

A river journey such as this can be popular with the whole family as there is often a surprise around every bend.

It may require more than a single day as the river is longer than one expects and there is a lot to see along the way.

A visit to Gary Johansen at Paeroa Marine (the guide for our trip up the Waihou) and the good folk at the Historical Maritime Park will also pay dividends prior to setting off.

The park has a huge amount of information and artefacts about the river's history and the staff are helpful. Rides on the Otunui and the smaller Ariana can also be booked at the park. Phone: (07) 862 7121 or email maritimepaeroa@xtra.co.nz.

* Mike Rose travelled up the Waihou courtesy of Gary Johansen of Paeroa Marine and Greg Fenwick of Yamaha Motor NZ.