World's first subsea desalination facility will start running in 2026

Flocean’s subsea desalination pod

From New Scientist by Vanessa Bates Ramirez

Flocean, a Norwegian company, is set to open the world’s first commercial-scale subsea desalination plant, an approach that could cut the cost and energy used to make seawater drinkable

Turning seawater into drinking water is so costly and energy-intensive that it’s untenable in most parts of the world, but a Norwegian company is trialling a new approach that could change that.
Flocean will launch the world’s first commercial-scale subsea desalination plant in 2026, and says its system will cut the cost and energy consumption of the process dramatically.

Global demand for water is going up, driven by population growth, climate change and industrial uses like data centres and manufacturing.
Meanwhile, fresh water is becoming less abundant due to droughts, deforestation and over-irrigation.

Land-based desalination currently produces about 1 per cent of the world’s fresh water supply, with over 300 million people relying on this source for their daily water needs.
The biggest plants are in the Middle East, where cheap energy makes the technology more feasible and water scarcity makes it more necessary.

The leading technology for desalination today is reverse osmosis.
The method pumps seawater through a membrane with microscopic holes that only allow water molecules to pass through, while salt and other impurities get filtered out.
The water has to be pressurised to push it through the filters, a process that requires vast amounts of energy.

🚨RÉVOLUTIONNAIRE !

🌊 💧 La Norvège pourrait avoir mis au point une technologie qui pourrait fournir de l'eau potable à TOUTE la planète (8 milliards d'humains).

Le tout avec moins d'électricité qu'une seule centrale nucléaire française.

Flocean annonce le premier système de… pic.twitter.com/8JYumrNTi6

— Philippe T (@brain_stimulus) February 19, 2026

Flocean’s approach is to plunge water-filtering pods deep into the ocean, separate seawater from salt at depth, then pump the fresh water back up to land.
By putting reverse osmosis pods deep underwater, the technology leverages hydrostatic pressure – the weight of all the water pressing down from above – to push the seawater through filtering membranes.

Less pumping means less energy consumption, around a 40 to 50 per cent reduction compared with conventional desalination plants, according to the company.
Plus, seawater is cleaner once you get below the sunlight zone (which extends to 200 metres below the water’s surface), which means the water doesn’t require as much pre-treatment before it reaches membranes.

“It’s fundamentally quite boring down there from a process and engineering perspective,” says Alexander Fuglesang, Flocean’s founder and CEO.
“It’s the same salinity, temperature, pressure. It’s dark. There’s not a lot of bacteria that can cause biofouling.”

The same hydrostatic pressure that pushes water through the membranes also helps disperse the salty brine by-product, which Flocean says is free of chemicals that might harm marine life.

For the past year, Flocean has been desalinating water at a depth of 524 metres at its test site at Norway’s largest offshore supply base, Mongstad Industrial Park.
Its commercial facility, called Flocean One, is being built at the same location, and will initially produce 1000 cubic metres of fresh water daily when it launches next year.
The operation can then be scaled up modularly by adding more desalination pods.

“Our philosophy is to keep the subsea units the same and scale by multiplication rather than by building ever bigger machines,” says Fuglesang.
Scaling up will involve engineering trade-offs at the system level, however.
Since more modules will share the same power supply and controls, Flocean’s engineers need to organise power distribution and the permeate manifold – the mechanism that directs purified water from multiple membranes to a single output line – so that scaling up is as straightforward as possible.

“This solution could become viable in suitable locations, providing affordable water if costs decline, but it has yet to be proven at large scale,” says Nidal Hilal at New York University Abu Dhabi.
“Broad municipal deployment likely depends on overcoming technical and economic challenges over several years.”

Cost reductions will be crucial to scale up the technology further, says Hilal, as it is still much more expensive than obtaining fresh water through conventional methods like pulling from lakes or aquifers.

Cleaning and maintaining the membranes will be one of Flocean’s biggest costs.
Advances in membrane technology will help; Hilal’s research group is working on electrically conductive membranes that use electricity to repel salt ions and foulants, keeping themselves clean and boosting throughput.
The researchers are also exploring ways to recycle single-use plastics into membrane materials, increasing sustainability while further reducing costs.
“More durable membranes and high-efficiency pumps can further lower operational expenses, while renewable energy integration reduces power costs,” says Hilal.

Flocean One should start producing fresh water in the second quarter of 2026.
If the technology works as planned, it could help Flocean get the backing to build bigger plants elsewhere.
“The biggest challenge for us is having perfect alignment,” says Fuglesang.
“We need the client, we need government permissions and we need strong financial partners.”

From compass to cosmos: charting the World Magnetic Model

 

The World Magnetic Model is a large-scale representation of Earth’s magnetic field. The blue and red lines indicate the positive and negative difference between where a compass points the compass direction and geographic North. 

Green lines indicate zero degrees of declination.

[Image credit: NOAA]

 

From National Geospatial-Intelligence Agency

 

At the center of our planet, a core of conductive iron alloys swirl, radiating heat and electrical currents.
This effect generates a magnetic field that extends from the center of the Earth out into the reaches of space, powerful enough to prevent solar winds from stripping the atmosphere from the planet.

 

While the magnetic field deflects the hazards of space, its impacts are felt at the terrestrial level as well.
The field has proven particularly useful for navigation — from migrating birds to humans sailing the seven seas.
For centuries, however, this important navigational aid was a source of frustration.
Mariners quickly learned their compass needles pointed not to the geographic North Pole, but to a magnetic pole — and it was moving.

The angular difference between true north and magnetic north, known as declination, varied unpredictably across the globe and over time.
A chart that was true one year could lead a vessel to ruin the next.

This challenge spurred a centuries-long quest to map and understand the Earth’s shifting magnetism, an undertaking that would require generations of collective scientific knowledge and take geomagnetic observation from the seas into space.

Today, the National Geospatial-Intelligence Agency continues the pursuit of geomagnetic study, using data gathered from seabed to space to craft models that help billions safely navigate our world – building upon the legacy of the explorers and scientists that came before.

 

The November 2024 version of the World Magnetic Model.

Credit: NOAA/NCEI and CIRES.

Pioneers of the Unseen

One of the first major leaps in geomagnetic study came at the turn of the 18th century.
Famed astronomer Edmond Halley — years before the comet that bears his name would make its predicted return — took command of the HMS Paramour, departing on a series of voyages.
Backed by the British Crown, his mission was to chart the magnetic declination of the Atlantic Ocean.
The resulting charts were the first of their kind, providing scientific verification that the magnetic field was not static.
However, these charts did not solve the issue that a single survey, no matter how accurate, was only a fleeting snapshot.

While the practical applications and limitations of magnetic navigation were being explored, it ultimately took another century for German mathematician Carl Friedrich Gauss to unlock the science behind it.
He theorized that the magnetic field was primarily generated from within the planet and ultimately provided the fundamental theoretical tools and mathematical frameworks still used by scientists today to model its complex behavior.
While Halley had charted the problem and Gauss provided the theory, it was an American scientist who would fuse these concepts into a global, operational mission.

Louis A. Bauer, the first director of the United States’ Carnegie Institution’s Department of Terrestrial Magnetism, made it his life’s work to elevate the study of geomagnetism, recognizing that a precise, unified model was essential for safe navigation and scientific progress.

In 1905, his department commissioned its first vessel, theGalilee.
However, the ship’s iron fastenings created too much magnetic interference.
To achieve the precision he required, Bauer convinced the Carnegie Institution to fund a vessel unlike any other: a ship built to be almost entirely non-magnetic.

Constructed from wood, copper and bronze, the Carnegieset sail in 1909.
On its maiden voyage, theCarnegieretraced Halley’s path from 200 years prior, determining that if they had followed Halley’s original compass headings, they would have landed in Scotland instead of their intended destination in England — a clear demonstration of the ever-shifting magnetic field.

TheCarnegie’s seven voyages produced an unprecedented volume of magnetic data, dramatically improving the accuracy of the world’s navigational charts.
However, Bauer’s grand endeavor came to a tragic halt in 1929 when theCarnegiewas sunk after a refueling explosion in Samoa, killing its captain and destroying its contents.
Though this ended the program, most of the gathered data had been copied and sent to Washington, preserving its scientific advancements.

The Final Frontier

Following the loss of the Carnegie, dedicated U.S. magnetic data collection paused for several decades before resuming in the 1950s with the military’s Project Magnet.
This survey program outfitted specialized aircraft with magnetometers, flying extensive missions across the globe to gather the vital data needed for military charts and navigation.

The dawn of the space age offered a revolutionary new vantage point, and by the turn of the millennia, the satellite era of geomagnetic research began in earnest.
Early missions, such as the Danish Ørsted satellite and the German CHAMP satellite, laid the foundation for modern satellites such as the European Space Agency’s Swarm constellation.
These orbital platforms could gather a continuous stream of precise, global data with a previously impossible speed, consistency and scale.

This satellite-derived data now fuels the modern World Magnetic Model.
The U.S. National Geospatial-Intelligence Agency and the U.K. Defence Geographic Centre sponsor the WMM, and the U.S. National Oceanic and Atmospheric Administration and the British Geological Survey produce it.
Updated every five years to account for the planet’s shifting field, the WMM is one of the world’s premiere geomagnetic models.

Today, the U.S. Department of War, the U.K. Ministry of Defence, the North Atlantic Treaty Organization and the Federal Aviation Administration, and many other major organizations and countries use the WMM.
It is also part of the dataset that makes up the World Geodetic System, which is used in countless navigation systems, including the GPS, in billions of smartphones and vehicles. 

Declination values for WMM2025 (dashed lines) and WMMHR2025 (solid lines) plotted together at 15 minute contours. 

Note larger deviations above tectonic features like the Appalachian Mountains. 

The Next Evolution

This widespread reliance on magnetic data creates a pressing need for an advanced and sustainable data source.
To meet this challenge, NGA looks to the future with MagQuest, a competition designed to stimulate innovation in geomagnetic data collection.
The initiative challenges solvers from industry and academia to develop new, independent and cost-effective methods for collecting the data needed to maintain and update the WMM.
By accelerating the development of novel solutions, such as constellations of small, highly accurate nanosatellites, MagQuest drives technological innovation, harnessing private-sector industry to deliver cutting-edge technologies.
Additionally, it is a vital national security imperative.
By fostering a domestic capability for geomagnetic data collection, NGA ensures that the U.S.
and its allies maintain their decisive navigational edge — receiving the most accurate and timely geomagnetic data available.

The tools may have evolved from canvas sails to satellites, but the fundamental mission remains unchanged: to precisely chart the Earth’s dynamic magnetic field and guarantee navigational accuracy for U.S. forces, allies and civilian users worldwide.

 Links :

• Air&SpaceForces : NGA Launches New Small Sats to Measure Earth’s Magnetic Field
• NOAA : WMM2025 and WMMHR2025 prove to be accurate models of Earth’s magnetic field 
• SpatialSource : Satellite will measure Earth’s magnetic field
• GeoGarage blog : Earth's magnetic North Pole moving closer to Russia

Admiralty vs Imray Charts: which should you buy?

From SailorShop by Christopher Doyle

Updated March 2026 with current pricing, the FB Imray joint venture and new guidance on chart storage.

Choosing the right chart matters.

You trust your charts to keep you safe on passage, and with two well-known names to choose from, it's worth understanding what each offers before you buy.

We're a family-run nautical bookshop with over 10 years' experience and a Master Mariner at the helm, so we've spent a lot of time with both Admiralty and Imray charts.

This article sets out the differences in format, pricing, coverage and practicality so you can make an informed choice.

Both publishers draw on the same official hydrographic survey data, so the underlying information is equally authoritative.

The differences are in how each brand presents that data, who it's designed for and how it's packaged.

Admiralty Charts

 

Admiralty charts are produced by the UK Hydrographic Office (UKHO), an executive agency of the Ministry of Defence. 

They're the standard for merchant navy and Royal Navy vessels worldwide, but they're also widely used by leisure sailors who value the traditional format and the international standards behind the cartography.

All Admiralty charts are now print-on-demand.

Every chart is printed from the UKHO's latest digital files with all permanent corrections applied.

You won't need to sit down with a stack of retrospective corrections before you can use the chart, which is a genuine advantage over pre-printed alternatives.

Admiralty has two product lines for paper charts:

Standard Nautical Charts are large-format charts with worldwide coverage, used by commercial ships and leisure sailors alike.

They cover everything from ocean passages to harbour approaches, and for less-charted waters or longer offshore passages they may be the only option in paper.

Priced at £49.50 each.

Small Craft Charts are designed for small boat coastal navigation around the UK and Ireland.

They use data from the Standard Nautical Charts at scales suited to inshore and coastal sailing

Both Admiralty Small Craft Charts and Imray charts are recognised by the MCA for use on coded vessels and fishing vessels up to 24 metres.

Priced from £17.80 each, with significant discounts for bulk orders.

A to-scale comparison of both Admiralty chart formats.

Admiralty charts: pros and cons

ProsConsFollow international hydrographic standards, trusted worldwide Standard Nautical Charts are expensive (£49.50 each) and physically large
Global coverage (Standard Nautical Charts) Not water resistant
Print-on-demand means every chart arrives with all permanent corrections applied Can appear cluttered to some users, especially at smaller scales
Available at a range of scales, from ocean overview to harbour approach Small Craft Charts cover UK and Ireland only. For further afield you'll need Imray or Standard Nautical Charts
Pick and choose individual charts rather than buying a fixed pack Small Craft Charts are sold as individual sheets with no wallet or folder.

You'll need to think about storage
No retrospective corrections to apply No supplementary information printed on the chart itself. Supporting data (tidal curves, tidal streams) is in a separate document on the Admiralty website

Admiralty Small Craft Charts

Admiralty Small Craft Charts (click to see the range)

If you're sailing around the UK and Ireland, Admiralty Small Craft Charts are well worth considering. Each chart is printed to order from the UKHO's latest digital files, so you always get the current edition with all permanent corrections applied.

The printed chart area is A2, though the paper itself is slightly larger.

The UKHO draws on data from its Standard Nautical Charts to produce these at scales suited to coastal and inshore navigation.

Weekly Notices to Mariners are available online for free, so you can check for safety-critical changes between purchases.

Each folio area also has a supporting document on the Admiralty website with chart notes, distress and safety communications information, tidal curves and tidal stream tables relating to the tidal diamonds on the charts.

Small Craft Chart pricing

Small Craft Charts are £17.80 each, but there are stepped discounts for bulk orders that make a real difference. 

Buy 5 to 9 charts and the price drops to £11.57 each.

Buy 10 to 14 and it's £6.23 each.

Order 15 or more and the price falls to just £4.45 per chart.

This creates some interesting maths.

Five charts (£57.85) cost less than four (£71.20).

And 16 charts at £4.45 each (£71.20) cost the same as four at full price.

If you're buying more than three or four charts, it's worth counting up and seeing whether the next discount tier saves you money.

We've written a separate article on getting the best value from Admiralty Small Craft Charts if you want to dig into the numbers.

We also sell bundled chart sets that match the old folio areas, so if you want full coverage of a region without having to work out which individual charts you need, those are a straightforward option.

A note on storage

Admiralty Small Craft Charts used to come in plastic folio wallets, but that's no longer the case.

Each chart is now sold individually and ships rolled in a cardboard tube (we bundle multiple charts into the same tube where possible).

The paper is slightly larger than the printed chart area, so you may want to trim it if you're fitting charts into a wallet or folder.

Some sailors keep their charts rolled.

Others fold them or trim them to fit an A2 wallet.

There's no single right answer, and it's worth thinking about what suits your chart table and storage space before you order.

It's a less tidy arrangement than Imray's wallet system, but the fact that every chart arrives with all permanent corrections already applied is a real practical benefit.

We should count ourselves lucky that paper charts are still being produced at all.

Imray Charts

 

Imray, Laurie, Norie & Wilson has been publishing charts since the constituent firms merged in 1904, though the individual companies trace their roots back to the mid-1700s, when they served merchant ships from the City of London.

For most of the past century, Imray has focused on the leisure sailor, and their charts reflect that: clear, practical and packed with the kind of information you actually want when you're planning a coastal passage or entering an unfamiliar harbour.

In late 2024, Imray announced it would stop printing paper charts after the 2025 season.

The news sent a ripple through the sailing world.

But in April 2025, Austrian cartographic publisher freytag & berndt stepped in, forming a joint venture called FB Imray to continue production.

FB Imray commenced operations from Vienna later that year with Imray's former managing director Lucy Wilson as Editor-in-Chief. 

The MCA has formally recognised FB Imray as a Private Chart Producer, and the charts continue to be produced to the same standards.

Imray paper charts are very much still available.

Like Admiralty, Imray charts are based on official hydrographic survey data licensed from national hydrographic offices.

Their strength is in how they present it.

Their network of local sources, built through decades of publishing pilot books and cruising guides, feeds into the chart content.

The result is charts designed from the start for coastal and offshore cruising rather than commercial shipping.

What sets Imray charts apart

Imray single charts are printed on Pretex paper, which is coated for water resistance and folds well without cracking.

Each chart folds to roughly A4 size and comes in a plastic wallet with a separate sheet showing the symbols and abbreviations used on Imray charts.

Storage is straightforward: wallet back in the chart table, job done.

Imray make excellent use of the available space.

Areas that would otherwise be blank are filled with harbour plans, tidal information and local contact details.

A single Imray chart can effectively do the job of several Admiralty charts at different scales, which means fewer charts to carry on board.

You don't need to buy separate Admiralty harbour approach charts for anchorages you might visit.

The trade-off is that the harbour plans are naturally smaller than a dedicated chart at that scale, but for most leisure purposes they give you what you need.

This matters more than it used to. Most leisure sailors now have a plotter or chart app handling primary navigation.

Paper charts have increasingly become the backup, the passage planning surface, the thing you reach for when you want to see the bigger picture or when the electronics go dark.

Imray charts suit that role well.

A single sheet gives you passage-level coverage and harbour approach plans, so you're carrying fewer charts and still covered for the areas you're likely to need.

For sailors who want paper charts that complement their electronic navigation rather than duplicate it, Imray's approach makes a lot of sense.

 

Imray chart series

Imray offers individual charts in several series, plus chart packs covering wider areas. All single charts fold to roughly A4 and come in a plastic wallet.

• SeriesCoverageSize (mm)C Series North West Europe 787 x 1118
• Y Series UK rivers, estuaries and coastal areas 640 x 900 or A2 (small format)
• M Series Mediterranean Sea 640 x 900
• A/B/D Series Caribbean 640 x 900
• E Series Atlantic Islands 640 x 900
• G Series Ionian and Aegean Seas 640 x 900
• 2000 Series (Chart Packs) NW European waters, Brittany, Mediterranean Spain A2

The Y Series comes in two formats. Some Y charts (Y16, Y17, Y18, Y23 and others) are 640 x 900mm. Others (Y44, Y47, Y48 and others) are the smaller A2 format and replicate individual sheets from the chart packs.

Some Y charts are also available laminated.

Imray's C Series single charts cover North West Europe.

Bear in mind these are large charts (787 x 1118mm unfolded), so check they suit your chart table.

Imray's M Series single charts cover the Mediterranean Sea

 
Imray charts: pros and cons

ProsConsClear layout designed for the leisure sailor Each chart covers a lot of ground, so the harbour plans are smaller than a dedicated chart at that scale
Single charts are water resistant (Pretex paper)

The colour scheme takes getting used to if you've trained on Admiralty-style charts, such as the RYA training charts
Harbour plans, tidal data and local information packed onto each sheet, reducing the number of charts you need to carry Not print-on-demand, so you'll likely need to apply corrections on receipt
Single charts fold to A4 and come in plastic wallets.

Neat and easy to store Some users find the packed-in extras make the chart feel busy
Chart Packs include a voucher for the Imray Navigator app (single charts do not)

Some find the Pretex paper less suited to pencil work and harder to read under red light. A 2B pencil works much better than a standard HB
Symbols and abbreviations guide included with each chart C Series charts are large (787 x 1118mm) when unfolded

How Imray keeps charts current

Imray charts are not print-on-demand.

When there are significant changes to a charted area, or a substantial number of corrections have built up, Imray publishes a new edition.

Between editions, they release reprints that incorporate all corrections applied to that date.

Correction notices for individual charts can be downloaded from the Imray website so you can keep your charts up to date between reprints.

Imray Chart Packs vs Admiralty Small Craft Charts

Imray Chart Pack coverage

Many sailors are drawn to the convenience of chart packs or folios.

A ready-made set of charts for a given area saves time and takes the guesswork out of which charts you need.

They're particularly useful for waters you sail regularly or for trips where you're not sure which harbours you'll end up in overnight.

Both Imray and Admiralty offer good options here, though they work differently.

One of Imray's chart packs

FeatureImray Chart PacksAdmiralty Small Craft ChartsFormat A selection of A2 charts covering a specific region, packaged in a plastic wallet.

Available loose-leaf (£59.95) or spiral-bound (£64.95) Individual A2 charts (on slightly larger paper) that you choose and combine to build your own folio.

We also sell bundled sets matching the old folio areas
Choice Pre-made packs. You buy all the charts for the selected area Pick and choose.

Buy only the charts you need
Water resistance Not water resistant Not water resistant
Packaging and storage Plastic wallet included No wallet.

Charts arrive rolled in a cardboard tube.

You'll need to arrange your own storage on board
Coverage UK and Ireland coastal waters, the Southern North Sea and Mediterranean Spain UK and Ireland coastal waters
Corrections May require retrospective corrections on receipt.

Correction notices can be downloaded from the Imray website Print-on-demand, so every chart arrives with all permanent corrections applied.

No retrospective corrections needed
Supplementary data Harbour plans, tidal data and waypoints printed on the charts themselves Tidal curves and tidal stream tables in a separate supporting document on the Admiralty website
Digital Chart Packs include a voucher for the Imray Navigator app No digital download included
Cost £59.95 (loose-leaf) or £64.95 (spiral-bound) £17.80 per chart, with stepped discounts: £11.57 each for 5-9 charts, £6.23 for 10-14, and £4.45 for 15 or more

A note on Imray Chart Pack coverage: the packs cover many popular UK cruising areas (the Solent, Kent and Sussex, Dorset and Devon, the Firth of Clyde, and others), but there are gaps.

There are no chart packs for the south coast of Ireland, the north east coast of England or much of Scotland.

For those areas, you'll need individual Imray C Series charts or Admiralty Small Craft Charts.

Colours

Colours matter more than you might expect when choosing charts.

Ask any group of sailors which brand they prefer and the colour scheme will almost certainly come up.

Admiralty charts follow the international colour standard used by hydrographic offices worldwide.

Deep water is white, shallows are blue, land is a buff colour and drying areas are green.

The white background gives a clean surface for pencil work and makes chart detail easy to read.

When you encounter colour on an Admiralty chart, it means something important about the depth or nature of the seabed.

If you've taken an RYA course, the training charts will have looked very similar.

Imray aren't bound by the international standards and have chosen a scheme that feels more intuitive if you're used to land-based maps.

Green land, golden beaches and deep blue sea.

It looks attractive and makes immediate visual sense, though it can take a while to adjust if you've trained on Admiralty-style charts.

Some users find the darker colours harder to read under red cockpit lighting at night.

Choosing the Right Chart

The choice between Admiralty and Imray comes down to where you sail, how you navigate and what you prefer to work with.

Where you're sailing.

Both publishers cover UK and Ireland well, though the formats and coverage patterns differ.

Imray Chart Packs don't cover every stretch of the coast, so check before you assume

For the Mediterranean, Caribbean and Atlantic Islands, Imray's single chart series are hard to beat.

For international voyages or less-charted areas, Admiralty Standard Nautical Charts offer the widest global coverage, though at a higher cost and larger format.

How you navigate.

If you're primarily using a plotter or chart app and want paper charts as a backup and planning tool, Imray's all-in-one approach (passage charts with harbour plans and tidal data on the same sheet) means fewer charts on board.

With Admiralty you'd typically buy charts at a range of scales for the same area, which gives you more detail but more to carry and store.

Neither approach is wrong.

It depends on how you use paper charts and what role they play alongside your electronics.

Personal preference.

Some of this just comes down to what you're used to.

If you learned on Admiralty-style charts, you might find Imray's colour scheme unfamiliar.

If you picked up an Imray chart first, the layout and harbour plans might feel more natural.

There's nothing wrong with using a combination of both, and plenty of sailors do.

Whichever you choose, make sure you also have a good pilot book, a current almanac and decent chartwork instruments to go with them.

 

Imray charts in the GeoGarage platform,

used in navigation mobile apps : 

Weather4D iOS, SailGrib Android, NavimetriX multiplatform, Squid iOS

Frequently Asked Questions

Are Imray paper charts still being printed?

Yes.

In late 2024, Imray announced plans to stop producing paper charts, but in April 2025 Austrian publisher freytag & berndt formed a joint venture (FB Imray) to continue production. Imray charts are still available and still being updated.

We stock the full range.

Are Imray charts as accurate as Admiralty?

Both are based on the same official hydrographic survey data, so the underlying information is equally authoritative.

The difference is in presentation.

Admiralty charts follow strict international standards and are available at a range of scales, so you can get very detailed coverage of a specific area.

Imray charts are designed for the leisure sailor, with carefully selected detail and useful extras like harbour plans and tidal information printed on the chart.

Each chart covers more ground, so there are compromises on the scale of individual harbour plans, but for most coastal sailing the level of detail is more than adequate.

Do I need paper charts for sailing in the UK?

For commercial vessels under 24 metres, the MCA now has a framework (SV-ECS) that allows approved electronic chart systems to replace paper charts, though compliant equipment is still limited and may not suit every budget.

For leisure sailors, there is no legal requirement to carry paper charts.

That said, they remain an important part of good seamanship.

Electronics can and do fail, and a paper chart on the table is still the best way to see the full picture when you're planning a passage or working out your options.

What's the difference between Admiralty Standard and Small Craft Charts?

Standard Nautical Charts are large-format charts with worldwide coverage, used by commercial ships and leisure sailors alike.

They cost £49.50 each. Small Craft Charts cover UK and Ireland waters at scales suited to small boat coastal navigation.

The printed chart area is A2, on slightly larger paper.

They start at £17.80 each, with bulk discounts available.

How much do nautical charts cost?

Admiralty Standard Nautical Charts are £49.50 each.

Admiralty Small Craft Charts start at £17.80 each, dropping to as low as £4.45 per chart if you buy 15 or more. Imray single charts vary by series.

Imray Chart Packs are £59.95 for loose-leaf or £64.95 for spiral-bound.

We offer free shipping on all orders over £50.

Which charts do I need for the Solent?

For the Solent, you have good options from both publishers.

The Imray 2200 Solent Chart Pack covers the area well in a single pack and includes a voucher for the Imray Navigator app.

For Admiralty coverage, our Small Craft Chart set for folio 5600 covers the Solent and its approaches.

 

Links :

• GeoGarage news : Imray nautical raster charts H2 2025 update

The ghost of Columbus and the Impossible geometry of the Piri Reis map

Top image: An illustration of a man in a turban, representing Piri Reis, standing before an ancient world map with a brass compass in the foreground.

Source: AI generated

 

From AncientOrigins by mariusalbertsen

In 1929, while renovating the Topkapi Palace in Istanbul, a theologian discovered a fragment of gazelle skin that would rewrite the history of cartography.
This was the Piri Reis map, a world chart compiled in 1513 by the Ottoman admiral and cartographer Piri Reis.
While the map is famous for its early depiction of the Americas, a new wave of academic research is peeling back layers of mystery that suggest the map is even more "impossible" than previously thought.
Using modern cartometric analysis and digital "mosaicking," researchers are finding that the underlying geometry of this 16th-century artifact mirrors a level of survey accuracy that defies the technology of the Ottoman era.

The Piri Reis map was not merely a single drawing but a compilation of at least 20 different source maps.
Among these, Piri Reis himself claimed to have used eight Ptolemaic maps, four Portuguese charts, and one "lost" map by Christopher Columbus.
Because Columbus’s own nautical charts have never been found by modern historians, the Piri Reis fragment is often considered the only surviving "ghost" of Columbus’s original geographic vision.
However, the precision of the latitudes and longitudes in the Atlantic sector has led scholars to wonder if the source material was far older than the Age of Discovery.

Mosaics of Accuracy: The Map That Shouldn’t Exist

Map from Piri Reis’ Kitab-ı Bahriye showing Europe and the Mediterranean.
( Istanbul University Library / Public Domain)

Recent studies using cartometric analysis, a method of comparing historical maps against modern satellite coordinates, have revealed a shocking discovery.
Researchers such as M. Marelić and B.Šlaus have argued that the Portolan charts, which include the Piri Reis map, were constructed as a "mosaic" of smaller, highly accurate regional surveys.
These individual "tiles" of the map show a geometric precision that is nearly twice as high as the overall composite.
This suggests that Piri Reis was working with source maps that were surveyed with sophisticated instruments, possibly involving early forms of trigonometry that were not widely documented in 1513.

The coastal detail of South America on the Piri Reis map is particularly striking.
It depicts the Brazilian coastline with remarkable accuracy, including the mouths of the Amazon and Orinoco rivers.
In some sections, the deviation from modern GPS data is less than 50 kilometers (31 miles), a feat that should have been impossible before the invention of the marine chronometer in the 18th century.
This has led some fringe theorists to suggest "lost civilizations," but mainstream academics are now looking toward a more grounded, yet equally fascinating, possibility: an advanced, forgotten tradition of medieval Mediterranean seafaring.

Tracing the Lost Charts of Christopher Columbus

Portrait of a Man, Said to be Christopher Columbus.
(Sebastiano del Piombo/Public domain)

One of the most tantalizing aspects of the Piri Reis map is the inscription where the Admiral admits his debt to the "Genoese infidel," Columbus.
According to the text on the parchment, Columbus possessed a book from the time of Alexander the Great that described the lands across the Western Sea.
This claim has sent historians on a hunt for the "Columbian source." 

If Piri Reis truly copied a map used by Columbus, then the inaccuracies in the Caribbean section of the map, such as the oversized island of Hispaniola, might actually represent Columbus’s own distorted belief that he had found the legendary island of Cipangu (Japan).

The map also features vibrant illustrations of the New World’s fauna.
It shows parrots, monkeys, and even mythical creatures like the "Blemmyes," headless men with faces on their chests.
While these seem like mere folklore, they are placed alongside surprisingly accurate descriptions of the climate and local inhabitants.
The Piri Reis map thus serves as a bridge between the medieval mindset of monsters and the Renaissance drive for empirical data.
It is a snapshot of a world in transition, where the mystical and the mathematical collided on a piece of gazelle skin measuring roughly 60 by 90 centimeters (2.0 by 3.0 ft)

 
Beyond Piri Reis: The Heart-Shaped Mysteries of the Ottoman Empire

Piri Reis was not the only Ottoman cartographer to produce "impossible" documents.
The Hajji Ahmed map of 1559, a cordiform (heart-shaped) world map, also shows a level of geographic knowledge that seems ahead of its time.
Most notably, it appears to show a land bridge between Siberia and Alaska, the Bering Strait, long before it was officially "discovered" by Vitus Bering in 1728.
When viewed alongside the Piri Reis map, a pattern emerges: the Ottoman Empire was a central clearinghouse for a global "intelligence network" of geographic data that has since been lost to the West.

The "Antarctica" controversy remains the most debated feature of the Piri Reis map.
Many have pointed to the bottom edge of the map, claiming it shows the Queen Maud Land coast of Antarctica without ice.
Skeptics, however, argue that this is simply the southern extension of South America, curved to fit the dimensions of the gazelle skin.
Recent cartometric shifting suggests that if you "unbend" the map’s lower edge, the coastline matches the Patagonian shelf with surprising detail.
Whether it represents a frozen continent or a distorted South America, the mathematical intent behind the lines remains a subject of intense academic scrutiny.

Photorealistic reconstruction of the ice-free Antarctic coastline at twilight – evoking the mysterious, ancient landscape that some believe the source maps behind the Piri Reis map may have depicted.

Ancient Archives or Accidental Genius?

As we move deeper into the 21st century, the Piri Reis map continues to challenge our understanding of the past.
The "Mosaic Theory" implies that there were ancient archives of geographic data, perhaps dating back to the Great Library of Alexandria, that were preserved by Islamic scholars while Europe was in the Dark Ages.
These archives would have contained the collective wisdom of Phoenician, Greek, and Roman mariners who had ventured much further into the Atlantic than history books currently admit.

Ultimately, the Piri Reis map is a testament to the power of synthesis.
Piri Reis was a master editor, weaving together threads of Spanish, Portuguese, Greek, and possibly even ancient nautical traditions into a single, cohesive vision of the planet.
While we may never find the "lost book" of Alexander or the original charts of Columbus, this Ottoman masterpiece remains a primary witness to a lost era of global exploration.
It reminds us that the history of how we mapped our world is not a straight line of progress, but a complex puzzle of discovery, loss, and rediscovery.

Links:

• Shifting Earth Crusts: Does the Ancient Piri Reis Map Pinpoint Atlantis?
• Piri Reis Map - How Could a 16th Century Map Show Antarctica Without Ice?
• GeoGarage blog : The Genoese brothers who disappeared looking for a ...  /  Colombus and the Piri Reis map of 1513 / Did the Piri Reis map show Antarctica before its discovery? / Sailing the mysteries of old maps
  

Inside America’s ‘secret’ island deep in the remote Pacific ocean

Take a peek inside the mystery and magic of Palmyra Atoll. 

“Deep in the middle of the Pacific Ocean is a small chain of islands so remote that its nearest continental neighbor is over 3,000 miles away. It’s a place where the norms of modern American life are instead replaced by a million seabirds and the gentle rustling of coconut palms. This is the US territory of Palmyra Atoll. And because of a unique set of circumstances, it stands as one of the most isolated, pristine, and inaccessible places on the planet. Not even American citizens can easily visit.” 

From Surfer by Dashel Pierson

A tiny US territory 1,000 miles south of Hawaii is one of the planet’s most pristine, inaccessible island chains.

Here’s how a lucky few actually get in.

 

Palmyra Atoll, as seen during its time as a naval base during WWII.YouTube

Key Points

Palmyra Atoll is an extremely remote, pristine U.S. territory in the South Pacific.
Public access is rare, restricted for research, stewardship, or with strict USFWS approval.
Visiting requires significant expense; only a few vessels can access at once.

Palmyra in the GeoGarage platform (NOAA nautical raster chart)

About 1,000 miles due south of Hawaii, sitting out in the South Pacific Ocean, there lies one of the most remote and untouched places on earth: Palmyra Atoll.

It’s a curious place, both geographically and administratively.

The low-lying island is totally isolated, making it home to a host of tropical wildlife including sharks, manta rays, giant clams, and a variety of seabirds.

 

It’s also controlled by the United States, once serving as a naval base during World War II, and yet, visiting Palmyra is extremely restricted.

 

How does one visit Palmyra? 

It is possible.

And for a select few, people can even spend extended periods of time there serving as stewards. 

 

Per the U.S. Fish and Wildlife Service:

 Public access to Palmyra Atoll is self-limiting due to the very high expense and difficulty of traveling to such a remote destination.

The Nature Conservancy owns and operates the only airplane runway on Palmyra and by boat, it’s a five to seven day sailing trip from Honolulu.
“With prior approval by the USFWS, privately owned vessels are permitted access to the atoll for up to seven days to see and enjoy the natural resources of the refuge. A maximum of two vessels are allowed at one time and no more than six vessels may visit in a single month. As no dumping of any kind is allowed within the refuge, private vessels must have sufficient holding tanks for all black and gray water to accommodate their needs throughout the entire length of stay.”

 

Links :

• NBC news : I agreed to live alone on the Palmyra Atoll for one year. Here's why and how I stayed for eight
• USGS : Palmyra Atoll, an island paradise in recovery