Astrolabe: Shipwreck find 'earliest navigation tool'

The instrument was once used by mariners to measure the altitude of the Sun during their voyages

photo : Philip Koch

From BBC by Rebecca Morelle

An artefact excavated from a shipwreck off the coast of Oman has been found to be the oldest known example of a type of navigational tool.

Ghubbat ar Rahib bay where the wreck is being excavated

with the GeoGarage platform (UKHO chart)

This copper-alloy disc, bearing the Royal coat of arms and the armillary sphere of Dom Manuel I is an important object although its precise identity & function is still unknown.
It does have features suggesting it could be an astrolabe, or part thereof. 
The item was found in 2014 in a shipwreck in the Indian Ocean as one of nearly 3,000 objects recovered from the wreck, but it had no visible signs of navigational markings - until now.Esmeralda Shipwreck - The Official Vasco da Gama Expedition

Marine archaeologists say the object is an astrolabe, an instrument once used by mariners to measure the altitude of the Sun during their voyages.

It is believed to date from between 1495 and 1500.
The item was recovered from a Portuguese explorer which sank during a storm in the Indian Ocean in 1503.
The boat was called the Esmeralda and was part of a fleet led by Portuguese explorer Vasco da Gama, the first person to sail directly from Europe to India.

Using an astrolabe

David Mearns, from Blue Water Recovery, who led the excavation and is the author of The Shipwreck Hunter, told the BBC: "It's a great privilege to find something so rare, something so historically important, something that will be studied by the archaeological community and fills in a gap."

The astrolabe was discovered by Mr Mearns in 2014, and was one of nearly 3,000 artefacts recovered during a series of dives.
The bronze disc measures 17.5cm in diameter and is less than 2mm thick.
"It was like nothing else we had seen and I immediately knew it was something very important because you could see it had these two emblems on it," said Mr Mearns.
"One I recognised immediately as a Portuguese coat of arms... and another which we later discovered was the personal emblem of Don Manuel I, the King of Portugal at the time."

The excavation team believed the object was an astrolabe, but they could not see any navigational markings on it.

However, a later analysis uncovered its hidden details.
Laser scanning work carried out by scientists at the University of Warwick revealed etches around the edge of the disc, each separated by five degrees.

The University of Warwick used laser scans to uncover etches on the astrolabe,
which helped navigators work out the height of the sun

This would have allowed mariners to measure the height of the sun above the horizon at noon to determine their location so they could find their way on the high seas.
Mariners' astrolabes are relatively rare, and this is only the 108th to be confirmed catalogued. It is also the earliest known example by several decades.

Mr Mearns said: "We know it had to have been made before 1502, because that's when the ship left Lisbon and Dom Manuel didn't become King until 1495, and this astrolabe wouldn't have carried the emblem of the King unless he was King.
"I believe it's probably fair to say it dates roughly to between 1495 to 1500. Exactly what year we don't know - but it is in that narrow period."
He added: "It rolls back this history by at least 30 years - it adds to evolution, it adds to the history, and hopefully astrolabes from this period can be found."

Links :

• NPR : Left By Explorer's Armada, Shipwreck Yields 'Earliest Known' Marine Astrolabe
• DailyMail : 'Earliest known marine navigation tool' is uncovered on the shipwrecked Esmeralda that sank off the Oman coast during a violent storm 500 years ago
• National Geographic : Rare Solar Navigation Tool Found in Ancient Shipwreck
• GeoGarage blog : The great explorers of Islam

Ocean acidification is deadly threat to marine life, finds eight-year study

Scientists haul in samples of seawater in Svalbard, Norway.

Greenpeace is working with the German marine research institute to investigate ocean acidification.

Photograph: Nick Cobbing/Greenpeace

From The Guardian by Fiona Harvey

Plastic pollution, overfishing, global warming and increased acidification from burning fossil fuels means oceans are increasingly hostile to marine life

If the outlook for marine life was already looking bleak – torrents of plastic that can suffocate and starve fish, overfishing, diverse forms of human pollution that create dead zones, the effects of global warming which is bleaching coral reefs and threatening coldwater species – another threat is quietly adding to the toxic soup.

Ocean acidification is progressing rapidly around the world, new research has found, and its combination with the other threats to marine life is proving deadly.
Many organisms that could withstand a certain amount of acidification are at risk of losing this adaptive ability owing to pollution from plastics, and the extra stress from global warming.

 Satellite animation of ocean salinity made using one of the same satellites

used to create the new estimates of ocean acidification.

Credit: ESA

The conclusions come from an eight-year study into the effects of ocean acidification which found our increasingly acid seas – a byproduct of burning fossil fuels – are becoming more hostile to vital marine life.

“Since ocean acidification happens extremely fast compared to natural processes, only organisms with short generation times, such as micro-organisms, are able to keep up,” the authors of the study Exploring Ocean Change: Biological Impacts of Ocean Acidification found.

Marine life such as crustaceans and organisms that create calcified shelters for themselves in the oceans were thought to be most at risk, because acid seas would hinder them forming shells. However, the research shows that while these are in danger, perhaps surprisingly, some – such as barnacles – are often unaffected, while the damage from acidification is also felt much higher up the food chain, into big food fish species.

An unhealthy pteropod shows the effects of ocean acidification, including dissolving shell ridges on its upper surface, a cloudy shell, and severe abrasions.

Photograph: Courtesy of NOAA

Ocean acidification can reduce the survival prospects of some species early in their lives, with knock-on effects.
For instance, the scientists found that by the end of the century, the size of Atlantic cod in the Baltic and Barents Sea might be reduced to only a quarter of the size they are today, because of acidification.

Peter Thomson, UN ambassador for the oceans and a diplomat from Fiji, which is hosting this year’s UN climate change conference in Bonn, urged people to think of the oceans in the same terms as they do the climate.
“We are all aware of climate change, but we need to talk more about ocean change, and the effects of acidification, warming, plastic pollution, dead zones and so on,” he said.
“The world must know that we have a plan to save the ocean. What is required over the next three years is concerted action.”

credit : WHOI

 

The eight-year study was carried out by the Biological Impacts of Ocean Acidification group (known as Bioacid), a German network of researchers, with the support of the German government, and involved more than 250 scientists investigating how marine life is responding to acidification, and examining research from around the world.
The study was initiated well before governments signed a global agreement on climate change at Paris in 2015, and highlights how the Paris agreement to hold warming to no more than 2C may not be enough to prevent further acidification of the world’s seas.

Governments will meet in Bonn in November to discuss the next steps on the road to fulfilling the requirements of the Paris agreement, and the researchers are hoping to persuade attendees to take action on ocean acidification as well.

courtesy of NOAA

Ocean acidification is another effect of pouring carbon dioxide into the atmosphere, as the gas dissolves in seawater to produce weak carbonic acid.
Since the industrial revolution, the average pH of the ocean has been found to have fallen from 8.2 to 8.1, which may seem small but corresponds to an increase in acidity of about 26%.
Measures to reduce the amount of carbon dioxide reaching the atmosphere can help to slow down this process, but only measures that actively remove carbon already in the atmosphere will halt it, because of the huge stock of carbon already in the air from the burning of fossil fuels.

Worse still, the effects of acidification can intensify the effects of global warming, in a dangerous feedback loop.
The researchers pointed to a form of planktonic alga known as Emiliania huxleyi, which in laboratory experiments was able to adapt to some extent to counter the negative effects acidification had upon it.
But in a field experiment, the results were quite different as the extra stresses present at sea meant it was not able to form the extensive blooms it naturally develops.
As these blooms help to transport carbon dioxide from the surface to the deep ocean, and produce the gas dimethyl sulfide that can help suppress global warming, a downturn in this species “will therefore severely feed back on the climate system”.

Links :

• The Guardian : Deep sea life faces dark future due to warming and food shortage / Finding Nemo? We may be losing him, says climate study 
• BBC : More acidic oceans 'will affect all sea life
• News Deeply : What Scientists Are Learning About the Impact of an Acidifying Ocean
• Climate Central : Ocean Acidification, Now Watchable in Real Time 
• GeoGarage blog : Satellite images to monitor ocean acidification in remote ... / 'The other CO2 problem': How acidic oceans will ... / Study: our oceans are so acidic they're dissolving ... / An acid test for policy / Ocean acidification : the other CO2 issue

ECDIS not being used as anticipated

Extract of original and revised passage plans  (note: all times UTC+1)

Reproduced from Admiralty Charts BA 1406-0 and 1408-0

by permission of the Controller of HMSO and the UK Hydrographic Office

From MarEx

The U.K. Marine Accident Investigation Branch (MAIB) has announced that it is conducting a safety study, in collaboration with the Danish Maritime Accident Investigation Board, to understand why operators are not using ECDIS as envisaged by regulators and the system manufacturers.

General cargo vessel MUROS ran aground at around 0700 UTC Dec 3 off Happisburgh, Norfolk, UK, North Sea, while en route from Tees UK to Rochefort France.

Vessel grounded on a sandbank on even keel, no damages reported, authorities said she may be refloated ot around 2030 LT with high tide.

The news follows the release of a MAIB investigation report into the grounding of the bulk carrier Muros.
In the early hours of December 3, 2016, the Muros ran aground on Haisborough Sand, eight miles off the Norfolk coast.

 Muros bridge layout

When Muros grounded, she was following a passage plan shown on its electronic chart and display information system (ECDIS).

 Reconstruction of ECDIS display at 02:50

previously 00:25 / 02:08 / 02:20 / 02:48
image courtesy of Maris / Red Ensigh Training / UKHO

The MAIB investigation found that:

• The vessel was following a planned track across Haisborough Sand. The passage plan in the ECDIS had been revised by the second officer less than three hours before the grounding and it had not been seen or approved by the master.
• A visual check of the track in the ECDIS using a small-scale chart did not identify it to be unsafe, and warnings of the dangers over Haisborough Sand that were automatically generated by the system’s ‘check route’ function were ignored.
• The second officer monitored the vessel’s position using the ECDIS but did not take any action when the vessel crossed the 10-meter safety contour into shallow water.
• The effectiveness of the second officer’s performance was impacted upon by the time of day and a very low level of arousal, and she might have fallen asleep periodically.
• The disablement of the ECDIS alarms removed the system’s barriers that could have alerted the second officer to the danger in time for successful avoiding action to be taken.

Muros’s passage plan on ENC GB300106

& Muros’s passage plan on ENC GB2A2182

The MAIB has recently investigated several grounding incidents in which the way the vessels' ECDIS was configured and utilized was contributory.
There is increasing evidence to suggest that first generation ECDIS systems were designed primarily to comply with the performance standards required by the IMO, as these systems became a mandatory requirement on ships, with insufficient attention being given to the needs of the end user, states the report.

“As a consequence, ECDIS systems are often not intuitive to use and lack the functionality needed to accommodate accurate passage planning in confined waters. This situation has led to seafarers using ECDIS in ways which are at variance with the instructions and guidance provided by the manufacturers and/or expected by regulators.”

Links :

• Gov.uk :  the report is available here / Accident Investigation Report 22/2017
• TradeWinds : ECDIS under fire after bulker grounding
• Pulse : Human perception problems of ECDIS electronic chart displays  
• Dutch Safety Board : Digital navigation: old skills in new technology, Lessons from the grounding of the Nova Cura
   

Volvo Ocean Race : version 2017-18

The new 2017-1018 route around the world

"If you are determined to be in the sailing game you have to do this Race" - Sir Peter Blake. 

See the Volvo Ocean 70s and their crews slamming through some of the roughest, most terrifying, and dangerous conditions on the planet while competing in the Volvo Ocean Race 2011-12.

The Volvo Ocean Race when it was previously called the Whitbread Round the World Race

Links :

• GeoGarage blog : Volvo Ocean Race: a test of skills, not boats / The unforgiving ocean with Volvo Ocean Race / Why we sail - a film about the Volvo Ocean Race / Join the adventure of a lifetime | Volvo Ocean Race 2014-15 / VOR at reaching / Passion for the sea

UK & misc. (UKHO) layer update in the GeoGarage platform

see GeoGarage news