….. new meaning.
Our Congo Canyon data acquisition has come to an end and, overall, its been quite successful, especially as we were also testing a range of new developments.
We have left 10 instrument platforms on the seabed for over a year – we’ll be back in November 2020 to collect them – and during this time we hope they will have recorded the passing by of a number of big sediment slides that geologists call turbidite flows.
The closest analogy would be an avalanche made of sand, gravel, cobbles and boulders of various sizes.
So what have we done, and where did we get to over the last seven weeks?
We started out in the Cape Verdes with lovely weather that would persist for the entire seven weeks which makes instrument deployments and recoveries so much easier.
After some bench testing of some new sensors that arrived from the manufacturers very late in the day ……..
……. that appeared to do what “it said on the can”, and which we successfully integrated into a datalogger to record their output …….
……. and test on the bench against something known – in this case underwater pressure sensors against the ship’s meteorlogical atmospheric pressure sensor …… all five different pressure measuring systems effectively follow the same trends, but with different measurement precisions …….
……. satisfied that the systems integrate into a datalogger ……. they are deemed worthy of the risk of a deep seabed test ……. which meant …….. making a bespoke cable ……… because every system from the diversity of manufacturers always seems to have a different type of connector attached!
Attach the result to a platform and …..
……. deploy it into the sea.
A few weeks later, and up they popped and we take a look to see what exactly has been recorded in the quiet of the deep seabed.
And with a sea this calm, instrument platform spotting as the come back to the surface is so easy, let alone catching them and bringing them back aboard!
This project involved working in the territorial waters of up to four separate nations which, in the case of Angola, required a trip into the port of Luanda to get final approval and pick up three Angolan observers.
Back out to sea, and our efficient and speedy deployments and recoveries freed up some time for some long barrel coring ….. the barrel in this case being almost as long as the ship’s working deck.
Once swung vertically, the heavy weight on top drives it into the seabed.
Getting the barrel out again isn’t always that easy as the sediment can be quite sticky.
For the test platforms. that were recovered only after a few weeks, they only required a small battery. For the instruments being deployed for a year, every space available in the datalogger tube was filled with batteries, strapped in to keep them all secure.
This in turn makes the platforms heavier than normal which, in turn, means we need to add more flotation (bolted to the side, to lift them back to the surface from the seabed.
The flotation add-on is made of syntactic foam whose closest analogy is an Aero chocolate bar made out of glass – lots and lots of small glass bubbles stuck together.
This kind of flotation has a relatively large lift relative to it volume, but not as large a lift as the large glass spheres that we use as standard – their downside is that they are quite big and not easy to strap onto the side as “trimming” flotation.
And, for us, this was a small data acquisition and its quite odd to have only one shipping container, let alone one that isn’t even full either outbound or for the return – even if ten platforms have been left on the seabed.
Partially empty containers actually make our lives difficult as it is a lot harder to tie everything down so that it doesn’t move in transit ……. with jammed full ones like. we normally ship, everything holds itself in place.
Our end point is Walvis Bay in Namibia – a port that is currently focused to supporting the offshore oil and gas industry.
Lost of items in the port pending shipping offshore to drilling platforms, and a lot of lorries ready to collect all the scientific containers being shipped back to the UK.
The offshore hydrocarbons industry requires a lot of support systems, including floating repair docks,
…. massive cranes …..
…. space to tie up production and processing vessels …… this one made the RRS James Cook look tiny in comparison.
And, along the way, we had two birthdays ….
…… which of course require a hand-made themed cake.
And …… finally …… we spend a lot of time surfing the web and surfing the high seas …….. how about surfing the sand dunes that Walvis Bay is best known for.
No broken bones thankfully.
And those back home moved onto the next development stage which ….. as always ….. require building a prototype – and the prototype in this case is a communications interface to better facilitate testing of every other new design by minimising the number of flying wires.
But regardless of what we build, at some point the biscuit tin “Faraday cage” appears to mask man-made electrical signals that everything around us seems to make, and whose size is bigger than the very small electrical signals that our instrumentation is designed to record.
The positive side of needing a Faraday cage, is that we get to eat the biscuits first.