News
Mark Milburn’s Cornish Wreck Ramblings, Part 1: Accuracy, inaccuracy and alternative co-ordinates
We are in a marvellous age of technology, where we can pinpoint a needle in a haystack within inches. In the days before GPS and even Decca, there were transits. Transits can be good or bad; a good transit can be as accurate as any GPS. A bad transit is just bad.
I once went looking for a plane wreck. It hadn’t been dived for a long time, and we wanted to see what was left. It was a forty five minute boat ride but the transits were supposed to be good. We had to line up a telegraph pole with the third tree, out of four, in the hedge behind.
Something had happened to one of the trees; there were now only three, all spaced out a little… so which one was the original third tree? We used the sounder to look but found nothing, so we guessed at one of the trees…. and found sand. So a good transit had gone bad!
Decca was an improvement over transits when you were further offshore. Towards the end of its life, the last version of Decca was quite good, but eventually GPS took over. GPS was a little all over the place to start with, so along came Differential GPS (DGPS), which used a known fixed local transmitter to correct any errors. These errors were deliberate errors used by the Americans, so the rest of the world would be at a disadvantage. Once the Americans no longer added their “fudge factor”, the D was no longer needed.
So, what could possibly go wrong now? A few years ago, there was a news item on the BBC about a wreck called the Antoinette. It had become exposed as the sand shifted in the Camel Estuary. The report stated it was on the Doom Bar; it also stated that the bomb squad had been tasked with removing the remains of the wreck as they were a hazard to shipping. I headed over with my camera, but found nothing, just sand. I then headed back to Padstow to say ‘Hi’ to the staff at the lobster hatchery. While there, I could see something going on in the middle of the river. I was told it was the bomb squad about to blow a wreck up. But that was Town Bar not the Doom Bar – they are over a mile apart. Not the most accurate of reporting! That was quite recent though; when looking for old wrecks, with old information, the difference could be a lot worse.
Surely though, modern GPS is infallible? It is very good, as long as the numbers are accurate. They could be written down wrong, accidentally or deliberately. They could be from an alternative dataset. Most people use WGS 84, World Geodetic System, which originated in 1984. Some people don’t.
Myself and some friends wanted to dive the wreck of the St George, which lays twenty miles off shore in a depth of sixty five metres, and we wanted an accurate position. We asked around, got some accurate marks, and headed out. Once in the area, we watched the sounder as we went over the co-ordinates, but all we found was a flat sea bed. We repeated this several times, but still nothing. Time was running out to dive at slack water, but the sea bed was completely flat all around us.
Then one of us remembered that the person who gave us the co-ordinates liked to use OSGB 36, a different dataset. We quickly changed the GPS to OSGB and headed off. We arrived at the new location, and lo and behold, there was the wreck. So the co-ordinates were right… just an alternative right.
So, every form of position fixing has potential errors. Sometimes, there is nothing you can do about it… except guess!
Find out more about Mark and Atlantic Scuba at www.atlanticscuba.co.uk.
The Ocean Cleanup, the global non-profit project, has removed a verified all-time total of ten million kilograms (22 million lbs.) of trash from oceans and rivers around the world – approximately the same weight as the Eiffel Tower.
To complete its mission of ridding the oceans of plastic, The Ocean Cleanup uses a dual strategy: cleaning up the Great Pacific Garbage Patch (GPGP) to remove the plastic already afloat in the oceans, while stopping the flow of plastic from the world’s most polluting rivers.
Through cleaning operations in the GPGP and in rivers in eight countries, the cumulative total of trash removed has now surpassed ten million kilograms. This milestone demonstrates the acceleration of The Ocean Cleanup’s impact, while underlining the astonishing scale of the plastic pollution problem and the need for continued support and action.
While encouraging for the mission, this milestone is only a staging point: millions more tons of plastic still pollute our oceans and The Ocean Cleanup intends to continue learning, improving and innovating to solve this global catastrophe.
This announcement comes as governments from around the world meet to continue negotiations to develop a new legally binding instrument to end plastic pollution at INC4 in Ottawa, Canada. Representatives of The Ocean Cleanup will be in attendance and the organization will be urging decision-makers to collaborate towards a comprehensive and ambitious global treaty which addresses plastic at all stages of its life cycle and in all marine environments worldwide, including in areas beyond national jurisdiction.
It is encouraging to see that the need for remediation is reflected in the various options for potential treaty provisions. It is essential that the final treaty contains clear targets for the remediation of legacy plastic pollution, and reduction of riverine plastic emissions.
Tackling plastic pollution requires innovative and impactful solutions. The treaty should therefore incentivize the innovation ecosystem by fostering innovations that make maximal use of data, technology and scientific knowledge – such as those designed and deployed by The Ocean Cleanup.
‘After many tough years of trial and error, it’s amazing to see our work is starting to pay off – and I am proud of the team who has brought us to this point.’ said Boyan Slat, Founder and CEO of The Ocean Cleanup. ‘While we still have a long way to go, our recent successes fill us with renewed confidence that the oceans can be cleaned.’
The Ocean Cleanup was founded in 2013 and captured its first plastic in 2019, with the first confirmed catch in the GPGP coming soon after the deployment of Interceptor 001 in Jakarta, Indonesia. After surpassing one million kilograms of trash removed in early 2022, the non-profit project has since progressed to the third iteration of its GPGP cleaning solution, known as System 03, and a network of Interceptors currently covering rivers in eight countries, with more deployments set for 2024.
About The Ocean Cleanup
The Ocean Cleanup is an international non-profit organization that develops and scales technologies to rid the world’s oceans of plastic. They aim to achieve this goal through a dual strategy: stemming the inflow via rivers and cleaning up the legacy plastic that has already accumulated in the ocean. For the latter, The Ocean Cleanup develops large-scale systems to efficiently concentrate the plastic for periodic removal. This plastic is tracked and traced through DNV’s chain of custody model to certify claims of origin when recycling it into new products. To curb the tide via rivers, The Ocean Cleanup has developed Interceptor™ solutions to halt and extract riverine plastic before it reaches the ocean. Founded in 2013 by Boyan Slat, The Ocean Cleanup now employs a broadly multi-disciplined team of approximately 140. The foundation is headquartered in Rotterdam, the Netherlands.
For more information, visit: theoceancleanup.com and follow @theoceancleanup on social media.
Marine Life & Conservation
Steve Backshall to headline Shark Trust’s flagship event: For the Love of Sharks
Join a host of amazing, shark loving, speakers including Steve Backshall and the Shark Trust team for an evening celebrating shark conservation at the Royal Geographical Society in London this November.
Date: 29th November 2024
Time: 6-10pm
Location: Royal Geographical Society, London
Tickets: https://www.sharktrust.org/Event/flos24
The event will be a celebration of all things shark. Those lucky enough to get hold of tickets will hear from engaging guest speakers with a passion for sharks.
The line-up includes (*subject to change if unforeseen circumstances arise)
Steve Backshall: One of television’s busiest presenters, BAFTA award-winning wildlife expert Steve has been passionate about the wild world ever since he was young.
Steve’s impressive TV career has taken him all around the world, investigating a wide array of species and environments. Steve has filmed over 100 hours of children’s wildlife programmes with the BAFTA award winning Deadly 60 franchise and recently, with Sky Nature, for his new series ‘Whale with Steve Backshall’. He has been a patron for the Shark Trust for 10 years.
Simon Rogerson: is a photojournalist specialising in natural history, diving and the sea.
He is editor of SCUBA magazine, the official journal of the British Sub-Aqua Club. Simon started his career as a crime reporter but gravitated towards his ‘less depressing’ interest in underwater exploration, joining the staff of DIVE magazine in 1999. In 2005 he was named ‘Editor of the Year’ in the PPA’s Independent Publishing Awards. Simon also works as a freelance writer, contributing frequently to the Sunday Times and Telegraph, in addition to BBC Wildlife, Esquire, and a host of international diving magazines. He is the author of a book, Dive Red Sea, published by Ultimate Sports. Now based in Berkshire, Simon has been a Patron of the Shark Trust for 20 years.
More speakers to be announced soon. Head to the Shark Trust website to learn more.
The evening will also allow guests the final chance to see the Oceanic 31, shark art exhibition. Some of the artwork will be auctioned/raffled at the event, while the rest will be auctioned online to raise money for the Shark Trust Oceanic Programme.
For the Love of Sharks is an evening with something for everyone who is interested and fascinated by sharks. Join the Shark Trust, their Patrons, Trustees and Staff, along with a host of supporters for this celebration of shark conservation.
For more information or to buy a ticket: https://www.sharktrust.org/Event/flos24
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