Wednesday 17 October 2001
Peter Blake history
March 19, 2020

“The Amazon has been a real eye opener – its shear size, power and beauty are awe inspiring. It is such a shame to see it treated the way it is.”
– John, Seamaster crew member

Another day on the river.

We will sure be glad to get to Manaus for a break.

From before dawn until after dark motoring against a strong current requires constant vigilance – particularly as we have found the charts to be so incorrect.

The drifting logs, branches, rafts of weed, planks and other debris are on the increase, so we are having to constantly weave between them.

Right now we are less than 100 metres from the river bank – in 50 metres of water, making a speed of 10 knots through the water – but advancing at less than 6.

Fortunately the worst of the heat of the day is easing away – it was impossible to walk on the decks between noon and 2pm without shoes.

I am having a breather today, so the Log comes from Don Robertson and John Morgan.

From Don:

A little milk in your coffee?

There is an awful lot of coffee in Brazil. However, when they put milk with it, does it take on the colour of the Rio Amazon? Alfred Russel Wallace, a nineteenth century naturalist seemed to think so.

Wallace classified the rivers of the Amazon according to their colour, which also helped define the source of the river, silt content and fish life.

Rivers were either:

Whitewater, as in the Amazon river where we are currently, or

Clearwater, such as the Rio Tapajos, where we have just been and,

Blackwater, like the Rio Negro where we are headed.

Whitewater rivers such as the Amazon are not rivers of boiling rapids that we may imagine, but are muddy or a murky yellow-brown. To describe them as café-au-lait coloured, as some books do, is enough to have you send the coffee back and ask for tea.

However ‘black tea’ is the description of the colour of blackwater rivers such as the Rio Negro where Manaus is situated. Our next destination.

The Rio Negro is the biggest tributary of the Amazon, the fourth largest river in the world and is 1400 miles long. We intend to travel many miles up the Rio Negro, perhaps 600 miles if river depth permits, to drop-off our ‘jungle team’.

600 miles is a lot of black tea.

At Santarem we left the Amazon and travelled up the Rio Tapajos, defined as a clearwater river (see logs 125 to 129).

There was a noticeable change in the colour of the water at Santarem where the muddy Amazon is joined by the Tapajos. The rivers run together at this point, half muddy, half pale blue, before the muddy Amazon swallows up the Tapajos.

According to our information, the meeting of the waters and this colour separation is most spectacular at Manaus where the Amazon and the Rio Negro meet. We will have to wait and see.

What makes these rivers differ in colour?

For those of you who would like a sprinkling of facts with your coffee-au-lait or black tea here are a few basics:

Whitewater rivers:

  1. With the headwaters of the rivers in the Andes, erosion supplies the large amount of sediments found in the rivers.
  2. Nearly neutral pH (7.0) i.e. neither acid nor alkaline.
  3. Relatively high electrical conductivity – a good general indicator of the amount of minerals and nutrients found in water.
  4. High concentration of microbes and inorganic particles.
  5. When the rivers flood each year they renew soil fertility, replenish dried out swamps and bring new life to the forests.
  6. The characteristic flora & forests flooded by these rivers is called verzea.

Clearwater rivers:

Carry light sediment loads – have less silt and humus because all the moveable material was eroded long ago.

The rivers have relatively poor nutrient levels as they drain from highly weathered and ancient geological regions.

  1. Vary from acidic to nearly alkaline (pH 4.5 to 7.8).
  2. Low levels of humic matter – 1/10th of that of blackwater rivers.
  3. Electrical conductivity rarely exceeds 6.0
  4. While called ‘clear water’ they cannot be classified as crystalline as visibility is only 3 to 4 meters at best.

Blackwater rivers:

  1. Minimum sediment loads but stained dark by organic compounds originating in plant communities growing on extremely sandy soil.
  2. Soils lack the micro-organisms to break humus, (decaying plant matter) down into chemicals.
  3. Visibility is usually less than 1 meter.
  4. The colour is derived from plant compounds of tannins, caffeines and phenols -resulting in the colour of dark tea.
  5. The acidity limits microbial activity and growth of aquatic flora & fauna, notably mosquito larvae.
  6. Flooded forests along black water rivers are called igapo.
  7. Extremely poor in nutrients.
  8. Acidity is usually around pH 4 to 5.
  9. Heavy rain washes the humic matter into rivers staining the water blackish or very dark brown.


From John:

What a transformation

I used to read the Blakexpeditions logs from my computer at work (morning tea time of course) and feel truly envious of the experience the crew were having in Antarctica. I am now onboard Seamaster and in the Amazon. I still read the daily logs in the evening (which Don informs me is later than when it is posted on the web site), but in the main saloon onboard Seamaster. To Peter and Alistair I am eternally grateful to be here.

I joined the crew at San Fernando near Buenos Aires, 3 days before departing. I instantly felt welcome – the crew really are a top bunch of people. We briefly stopped at the beautiful Yacht Club Argentino in down-town Buenos Aires on our way out of the River Plate.

Out of the river and into the Atlantic, I was not sure what my role onboard would be. I soon realised that I was not just a guest and was made to feel like part of the expedition. Heading towards Rio de Janeiro, we stopped at Ilha Bella (Beautiful Island) as we were running ahead of schedule. And a beautiful island it was – very tropical, with palm trees, beautiful beaches and lovely welcoming people.

4 days in Rio and off up the coast into the tropics, sailing with the trade winds. It was amazing sailing, running and reaching with winds averaging 25 knots for days on end. We lowered each other into the water in a harness while sailing at 10 knots, even some of the older crewmembers (no offence Don and Roger) participated. I cannot wait to develop my films.

We tried several different sail combinations and I have learnt so much about big boat sailing and passage making.

Entering the Rio Para was treacherous – sandbars and fishing boats everywhere, something we have become used to. The atmosphere onboard began to change, a realisation the expedition was about to begin. We stopped at Belem, for final preparation and supplies for the trip up to Manaus. I could not believe the supplies required for the expedition.

The cabin fans had to be my most favoured purchase, as I was having trouble sleeping in the heat.

Making our way up to Santarem, through the narrow waterways that link the Rio Para to the Amazon, I got my first glimpse of river life, with many a family or child coming out to meet us from their homes on the river bank. One afternoon Marc, Leon, Roger and I went in the RIB to get a closer look at a fisherman pulling in his nets. He was friendly and invited us onboard to give him a hand. After a minute of us pulling his net in I could see why – extremely hard work in the heat. We pulled up various kinds of fish, including a medium sized Peacock Bass with a perfectly round sizable piranha bite taken out of it. I was definitely not getting in the water.

Upon arrival at Santarem, we passed through the changing of the waters, a definite line from the brown of the Amazon to the welcoming swimmable blue of the Rio Tapajos. And swim I did, barely refreshing however, as it was only a few degrees colder than the air. From Santarem we headed further up the Rio Tapajos in search of lakes for diving. Before each expedition ashore we were thoroughly briefed on the dangers and knew exactly what was required. I felt comfortable knowing that all precautions had been taken, as there was talk of many nasties including anacondas. We visited various lakes, enabling me to go snorkelling and paddling in the kayaks.

The next adventure was taking the 2 inflatable dinghies, full with gear, and 6 people in each, up a tributary on a rece’ trip. What was meant to be a 2 and a half-hour trip each way kept extending itself, so we decided to stop when one of the dinghy’s fuel supplies was getting low.

We did not make it to the waterfall, but we did stumble across various tranquil river villages. I could not believe how friendly the people were, shy at first, but once the initial barriers were broken they were extremely welcoming. So far from civilisation, yet they had churches, schools, small surgeries and post offices.

They informed us that the government is cutting their funding and conditions are deteriorating. After a not so long trip back to Seamaster, Ollie told us he had found a map of the area on his computer. We had barely made it half way, even though we had covered the distance from Auckland to Great Barrier Island in the 4.5 metre dinghies.

It was decided to try the same route in Seamaster. Janot, Charlie and I were in the dinghy frantically getting depth soundings, quite stressful, as we were responsible for the route Peter was steering. Random soundings of about 100 metres apart, I was steering and heard Peters voice on the VHF, “we have run aground” – not my most memorable moment. I sat stunned for a few seconds. “Not to worry” I was informed – the centreboards were lifted, and she reversed right off.

We must have narrowly missed the sandbank in our soundings. With my heart in my mouth we continued, eventually making it to where we stopped the previous day in the dinghies.

A smaller team went up to the waterfall, which apparently was amazing. I stayed behind, creating a mud chart with Alistair and Charlie to ensure a safe departure. We also mingled with the locals. Charlie and I swapped places with 2 local village people and attempted to sail their Bongo home. After much amusement (mostly on their behalf) we finally made it. You would not believe how unstable the Bongo’s are, and children as young as 3 make it look simple. We are now 2 days away from Manaus, my final destination for this expedition. I came into this trip with no expectations but will be leaving feeling truly gratified for what I have seen, been part of and the friends I have made. The Amazon has been a real eye opener – its shear size, power and beauty are awe inspiring. It is such a shame to see it treated the way it is.

The real adventure starts for Blakexpeditions after Manaus and it is back to my office and my envious log readings during morning tea.

Best wishes to Peter and the crew for the rest of the expedition.


It’s now 4pm – 2 more hours and we will need to anchor for the night. Almost 12 hours of dark and 12 hours of daylight here near the equator – in all months of the year.

We keep Seamaster well lit all night – for safety reasons. But the lights attract some varieties of insects – en mass. Hopefully we won’t have a repeat of the clean-up operation that we had this morning.

All the best from the Seamaster crew.

Kind regards,

Photo credit: Don Robertson