The Nine Most Incredible Nautical Phenomenon

June 12, 2015

Cruising atop the ocean with waves gently lapping against the hull of your ship – a picturesque holiday to be sure, but there are a few rare occurrences that you may never no matter how many times you sail the sea. Here we’ve compiled the ten most incredible nautical phenomenon, with some sights that you may think are literally too incredible to be real…


1. Maelstroms

You won’t be blamed if you hear the word “maelstrom” and think of Moby Dick or even Edgar Allen Poe’s A Descent into the Maelstrom. A popular theme in nautical-themed fiction and literature, the maelstrom is a powerful whirlpool with a considerable downdraft. A maelstrom can occur after a tsunami or sinkhole opening up. Luckily you cruisers shouldn’t worry – even in the worst maelstroms large vessels are rarely in any danger!

Nautical Phenomenon

The Nine Most Incredible Nautical Phenomenon

The Kauai Maelstrom, Hawaii Image Credit

2. Noctiluca scintillans

Bit of a mouthful? How about “Sea Sparkle”? Yes the Noctiluca scintillans is a miniscule bioluminescent life form that floats about in our oceans. How miniscule? How about between 200 and 2,000 micrometres. That means, at its largest, the Sea Sparkle is only around 2mm in diameter. You can find Sea Sparkles all over the world crowded together in shallows and along the coast. When disturbed they give off beautiful bright colours which can illuminate the sea. Truly beautiful.

Nautical Phenomenon

Noctiluca scintillans illuminating the shore Image Credit





We recommend turning the volume down!

3. Ice Stalactite

Also known as a Brinicle (brine icicle), ice stalactites form beneath sea ice when freezing cold saline water meets ocean water – essentially creating an undersea icicle. Brinicles have the potential to reach the sea floor with their sheer length, but this can only occur in somewhat more shallow waters – in deeper water the brinicle is likely to break on its own weight alone.

Nautical Phenomenon

A diver investigating a brinicle Image Credit


4. Convergence of the Baltic and North Seas

Near Skagen around the northernmost point in Denmark you’ll be able to see where the Baltic and North Seas meet. It’s fascinating – the seas have different densities and therefore cannot properly merge. What we’re left with is two clearly different coloured seas meeting another, creating a huge border in the water being marked like a line in the sand. The Baltic is not tidal so it retains much of its water and the rivers that empty into the Baltic help keep a low salinity, which is what prevents it from merging with the North Seas, giving us this marvellous natural wonder.

Nautical Phenomenon

The two-toned sea is a clear divide between the North Sea and the Baltic Image Credit


5. Baltic Sea Anomaly

Gather round conspiracy theorists! Let’s go back to the Baltic one more time, for at its depths is a most frightening sight… Is it a UFO? A rock formation? A sunken ruin? In any case, the Baltic Sea Anomaly has raised many questions and much controversy since its discovery in June 2011. Some scientists have claimed that it resembles a man-made structure, whilst others claimed that it’s entirely possible that it naturally formed on the seabed. Regardless whether it was made under the sea, on land or even in space it’s an incredible discovery.

Nautical Phenomenon

You can understand why some people thought the formation was alien! Image Credit


6. Underwater Crop Circle

For a while, strange geometric circles appearing on the seabed near Japan had divers confused. These circles were beautiful, intricate and most definitely not made by chance. A rogue wave caused perfect geometric shapes on the seabed below? I sincerely doubt it! The truth is actually far more interesting…

Nautical Phenomenon

Looks mysterious, no? Image Credit

It’s all the work of the puffer fish. Small five-inch puffer fish swimming about the seabed kicking up sand – and why? Well, to attract a mate of course! Scientists believe that all the digging the male puffer fish get into is to dig up the finest sand, suitable for laying eggs in – perfect for a female! It’s likely that the amazing shapes created in the process is just a happy accident, but we think it just makes the whole ordeal that much more romantic… “Not to worry dear, not only did I make the bed but look how nicely I’ve laid everything out!”

7. Red Tide

Ever seen the sea turn red? If you have, then it was probably a huge school phytoplankton! These plant-like single-celled organisms gather together and form the visible discolouration of the sea, varying from purple to red or green. It’s an astounding thing seeing the sea change colour, but we don’t recommend taking a dip!

Nautical Phenomenon

Dyed a deep red, you can see why people would call it the Red Tide Image Credit

8. Cappuccino Shore

Essentially a huge amount of sea foam, a Cappuccino Shore is named for the foam’s similarity with what you may find atop your coffee. This can occur after a massive amount of dissolved organic matter from offshore sources, mixed with agitated seawater. One source of dissolved organic matter can actually be the aftermath of the Red Tide! The UK has even seen its fair share of sea foam, including metre-high drifts of sea foam in Lancashire in 2011 and in September 2012 sea foam coated the beach front of Aberdeen.

Nautical Phenomenon

A thick, frothy foam laps over the sea wall in Cape Town Image Credit


9. The Bloop

In 1997 hydrophones across the Pacific detected something that scientists still don’t quite understand. A loud (very loud) ultra-low frequency sound was heard at stations more than 5,000km away from one another.  Theorists got straight to work speculating what the sound could be and many excitable sources are all too eager to believe The Bloop is a giant creature of some sort swimming about the Pacific.

Is it a Cloverfield-esque giant sea creature sleeping on the ocean floor? Eh, probably not. Scientists are now saying the most likely source of the sound is the cracking of a giant ice shelf in Antarctica. The sound can be carried thousands of kilometres through the ocean and bears a striking similarity to The Bloop… Although, a giant sea creature would be interesting, wouldn’t it?


Well the ocean is an utterly fascinating place – almost as interesting underneath the ocean as it is cruising above it! But we’ve got to ask, what’s the most fascinating thing you’ve seen on your cruise? Dolphins joining your voyage?  A miraculously good karaoke session? Let us know!