We had to anchor Seamaster in eleven metres of water, far further out in the river than we had planned; it’s a changing place and the depths on the charts can’t be relied upon. Our first choice only had 2.5 metres of water instead of the 12 metres expected.

With an hour to go before sunset we launched the red RIB - motored slowly into the shore around a mile away - through a narrow entrance with the island of Acara’ Acu to port and a shallow sand bar only 50 metres away to starboard. Lush undergrowth and large trees met the river on the island shore - with pink dolphins playing in the narrow channel. We spent some quiet moments just drifting with the slow current - there was no wind at all.

The trees soon gave way to water plants and reeds - a hiding place for caimen and who-knows-what-else. A further mile inside the entrance we came across a large log floating end-up out of the water - with a dugout canoe tied up to a drooping vine under some trees nearby. The pink dolphin continued to play around us, snorting in a very distinctive way - quite different to the clean “whoosh” of the common dolphin. They are an extraordinary colour - almost like something out of a cartoon, almost unreal.

The sun set on the hazy western horizon - the glow sending a golden path straight across the still waters of the lagoon to us.

Back onboard the crew tried their hand at fishing, using some meat as bait - but apart from a few bites had no luck.

It was a very quiet night with little wind - a few more insects were evident but the screens on all openings kept most out of the interior.

On Ollie’s watch in the middle of the night he found a bat hanging just above Franck‘s hammock - looking down at him. We had passed a cattle farm in the late afternoon and Marc thought it had probably come from nearby there.

Franck didn’t have his mosquito net in place - but from now on they will definitely be on all hammocks at night. Even though there may be few insects at the moment, the potential problem from the vampire bats is worse. They are known to carry rabies and leptospirosis. The mosquito nets should keep them away.

We all take our anti-malarial tablets each day, but there is nothing to take to help prevent against dengue fever - that will become more and more prevalent the further we travel up river. The correct grade of insect repellent and the wearing of long-sleeved shirts and trousers tucked into boots will give the most protection.

We left before sun-up this morning; it looks a similar day to yesterday - a wide brown stretch of water, with the hills and mountains now giving way to low land once again - a dark green line of jungle with a much brighter green of the grasses and reeds bordering the river’s edge - and long sandy beaches.

We have seen a container ship today - heading up river; as well as a number of passenger boats that call into the small villages at the side of the river; and a cruise ship from the Bahamas.

Paulo told us that it costs only 140 reals (about US$55) to travel the 6 days from Belem to Manaus on one of the local boats - sleeping in your own hammock - or twice as much for a cabin.

The Amazon River varies enormously in depth and width - sometimes 20 metres deep and 4 miles wide - at others 60 metres deep and 2 miles wide. But a HUGE amount of water flows to the sea via this river - an estimated 160,000 to 200,000 cubic metres per SECOND into the Atlantic Ocean.

This river is longer than from Berlin to New York.

It is vast in every respect.

We are pleased that we are here during the dry season, with a slower flow; what it is like at the peak of the rainy season must be very different.

There was not a cloud in the sky this morning - but the blue is a hazy blue - not crisp and clear like the Southern Ocean.

The sun rose orange-red - but soon turned to a white-hot disk that quickly activates the day in this part of the world.

Around the middle of the day, Ollie mentioned that we were coming level with another small river entrance that led away parallel to the main river for a number of miles, past Ilha Gurupatuba and up to the town of Monte Allegre, before rejoining at a second opening back onto the Amazon.

We launched the RIB and headed off - planning to meet Seamaster up-river a couple of hours later.

It was a very interesting time - motoring past small farms, seeing children playing in the river, pigs and horses cooling off in the river, and large green and black iguana lizards that watched us as we sped by, or lazed in the branches of trees and hardly opened an eye when we stopped to look. The vultures circled overhead or sat staring from the tops of trees. There were numerous large, snow-white herons, flashy kingfishers, black Amazon cormorants and one green parrot.

We even came across an iguana swimming across the river entrance - surrounded by a number of pink dolphin and the smaller grey dolphin.

The afternoon has been another hot one - motoring downwind directly into the sun - but we have anchored early off the entrance of Rio Curua. This entrance also has many pink dolphin feeding across it.

The younger members of the crew have put on their boots and are off in the RIB to look further up-river and possibly ashore. Marc is itching to get into the water and swim with the dolphin. He says: “if the dolphin are present, the piranha aren’t.” It’s an interesting theory!!

Ollie has the hydrophone in the water - and the rest of us are sitting in the shade in the cockpit listening to the sonic clicks of the dolphin - it’s adds a whole new dimension to what we are looking at.

The cruise ship we saw this morning, the Clipper Adventurer, is anchored nearby - with their passengers away in large black zodiac inflatable dinghies. Their itinerary means that we may see them again over the next few days.

Don and Franck have been likened to paparazzi ever since we anchored - endeavouring to get the definitive shots of the pink dolphin - because they really are so extraordinary.

7pm: Our dinghy team is back - having seen large flocks of green parrots. We plan to return after dark to look for caimen by torchlight. It makes for a different Saturday night to normal.

That’s about it from me.

I’m the hottest I have been all day.

Even with the fan in the communications room throwing a full blast of air straight at me, the air remains hot and dry, giving little relief.

A long shower on the aft deck in the late evening breeze is the only thing that will help - that and a cold beer in a few minutes time.

Sometimes it is worth being hot for the luxury of that first icy mouthful.

Until tomorrow,

All the best from me and the Seamaster crew.

Peter.