A Santorini boat trip is a sea outing around Santorini, the Cycladic island in the southern Aegean that surrounds a flooded volcanic caldera. The trip is one of the Greece Tours on Greece Ville, listed with the other Santorini tours.
This post covers Santorini in numbers, the old pumice quarries, the depth of the water, the Minoan eruption and the sea, the islands on the horizon, seabirds, why the Aegean is salty, knots and nautical miles, lighthouses, the island name, and the questions that come up on board: glare, emergency numbers, jellyfish stings, ears, waterproof phones and food safety in heat.
What is a Santorini boat trip?
A Santorini boat trip explores an island group in the Cyclades. The whole ring of Santorini islands measures about 16 km across. Santorini lies 128 nautical miles from the port of Piraeus. Ios lies 19 km north of the Santorini group.
On a Santorini boat trip, the land is easy to measure. The municipality of Santorini, with its islets, covers 90.69 square kilometres in total. The Thira regional unit, with Santorini, covers 314.8 square kilometres.
Santorini is the 36th largest Greek island, at 76.2 square kilometres. Eleven Cyclades islands are larger, so Santorini ranks twelfth in the group by area. Anafi lies 22 km east of the Santorini group.
During a Santorini boat trip, the curved shape of the main island stands out. The main island runs 17.4 km from Cape Mavropetra in the north to Cape Exomytis in the south.
The island is 1.2 km wide in the north and about 6 km wide in the south. The flooded caldera, a large sea-filled crater, has a rim of roughly 60 km around it.
- Crete: The island of Santorini lies 113 km north-north-east of Heraklion, which is on the island of Crete.
- Attica: Santorini lies 186 km south-east of Cape Sounion in the region of Attica.
- Population: Only Syros, with 21,507 residents, and Naxos, with 20,578, have more people than Santorini.
Therasia had 233 residents at the 1991 census, which is an official count of people. It had 268 at the 2001 census.
Which pumice quarries line the shore of a Santorini boat trip?
A Santorini boat trip follows shores where pumice, a volcanic rock, was once quarried. Pumice was loaded onto ships at eleven sites, including Balos, Plaka, Fira, Katofira and Therasia. Pumice quarrying began in the 1850s at places such as Balos harbour near Akrotiri.
On a Santorini boat trip, quarry history starts with a French botanist named Tournefort. He wrote that Santorini was a genuine pumice quarry. He also wrote that the rock allowed cutting into large pieces.
Theran earth is volcanic earth dug on Santorini. A royal decree of 1836 put the mining of this earth under state control. The same decree also made the digging sites public property.
On a Santorini boat trip, old mine remains lie scattered on Therasia and in the caldera. The caldera is the crater left by the volcano. Wagons and fences from the mines lie there too.
In 1835 Egypt’s ruler Mehmet Ali secured Santorini earth for works on the Nile. Only Greek ships carried it. Harbour works at Trieste used the earth from 1842 to 1846. Fiume followed in 1850.
- Peak output: The mines’ two biggest years were 1898, with 70,700 tons, and 1901, with 80,169 tons.
- Old methods: Miners dug in the open with hoes and sent the earth down pipes into boats.
- Late years: Small producers dug with simple tools until 1970, and a number turned old vineyards into mines.
In the early 1900s, the earth helped the Greek cement industry boom. The industry’s first firm opened at Elefsina in 1902.
How deep is the water on a Santorini boat trip?
A Santorini boat trip happens in the sea inside a caldera, which is a large volcanic crater. The deepest point of its sea floor is about 390 m below sea level. The caldera has three separate basins: North, West and South.
On a Santorini boat trip, the North Basin is the largest and deepest part of the sea floor. It is 389 m deep and lies between the Kameni islands, Thirasia and northern Santorini.
The smaller West Basin lies between Aspronisi, Palea Kameni and southern Thirasia. It is up to 325 m deep. Its sea floor slopes gently in the west but steepens close to Thirasia and Aspronisi.
During a Santorini boat trip, the South Basin covers a larger area than the West Basin. A chain of volcanic domes runs north-east to south-west and separates the South Basin from the others.
A volcanic reef near Fira Port has grown upward. It started 300 m below sea level and now reaches 40 m below sea level. The caldera walls rise to over 300 m above sea level.
- Channel link: A narrow, steep-sided channel 300 m deep links the North Basin to a feature outside.
- Depth gap: The South Basin is about 28 m shallower than the West Basin.
- Sediment layer: One layer of caldera fill is volcanic sediment from the early underwater stages of Kameni volcano.
Aspronisi is a small islet that frames the West Basin. The North Basin holds the deepest water of the three.
How did the Minoan eruption shake the sea around a Santorini boat trip?
A Santorini boat trip crosses waters that the Minoan eruption once changed. Scientists found its ash in 41 cores taken from the Aegean sea floor during a research cruise. Tsunamis, which are giant sea waves, also struck coasts in Turkey and Israel.
On a Santorini boat trip, the water covers eruption traces. Flows that entered the sea carried on as turbidity currents, which are underwater flows. They left a layer in cores east of Santorini.
Ash and pumice fell hundreds of kilometres away. Pyroclastic flows, which are fast hot clouds, reached only kilometres beyond the shore. A 2023 study puts the eruption at 34.5 cubic kilometres of dense rock.
During a Santorini boat trip, the sea lies where tsunamis once travelled. Layers at Çeşme-Bağlararası on the Turkish coast record at least four tsunami arrivals. A second wave followed soon, while ash still fell.
Çeşme Man was a young man found with a dog in the tsunami rubble. His are the only human remains found in eruption deposits. As ash fell, fires burned across the Aegean.
- Volume: Floating pumice rafts drifted far and settled elsewhere, so the total eruption volume stays uncertain.
- Tsunami sand: Near Didim and Fethiye, tsunami sand 10 to 15 cm thick lies directly under volcanic ash.
- Farthest reach: Off Caesarea, a sea-floor deposit up to 40 cm thick possibly marks the tsunami’s farthest reach.
Tsunami waves do not depend on wind, so their deposits can lie where no ash fell.
Which islands rise on the horizon from a Santorini boat trip?
A Santorini boat trip begins in the Cyclades island group of Greece. Folegandros lies 22 miles north-west of Santorini and 15 miles east of Milos. Anafi and Santorini form the south-easternmost part of the Cyclades. Anafi is 150 miles from the port of Piraeus.
On a Santorini boat trip, Sikinos is another island in the area. Sikinos lies 14 miles from Folegandros and 10 miles from Ios. It also lies 102 miles from the port of Piraeus.
Sikinos has two near-equal summits. Troulos reaches 553 metres, and Agios Mamas reaches 549 metres. The island covers 41.676 square kilometres and has 40 kilometres of coast. Folegandros covers 32.216 square kilometres.
On a Santorini boat trip, Ios is one more island. Ios is 111 nautical miles, or sea miles, from Piraeus. It is 72 from Heraklion and 55 from Ermoupoli, the Cyclades capital.
Amorgos lies 136 nautical miles from Piraeus, south-east of Naxos. The island covers 126.346 square kilometres. Six small islands between Amorgos and Naxos make up the Small Cyclades, including Keros, Iraklia and Donousa.
- Folegandros: Its tallest hills are Agios Eleftherios at 415 metres and Panagia at 365 metres.
- Anafi: Its highest point is Vigla, 582 metres tall, in the middle of the island.
- Ios: Its peaks are Xylodema at 660 metres, Kostiza at 586 and Prophetis Elias at 490.
Greek Wikipedia calls the limestone rock at Anafi’s eastern tip a monolith, meaning one huge stone. It is the second-largest in the Mediterranean after Gibraltar.
Which seabirds fly over a Santorini boat trip?
A Santorini boat trip that runs from April to July falls in the Eleonora’s falcon season. These falcons reach Greece from early April, and the last birds come by mid-July. They hunt from heights of up to 1,000 m above land or water.
On a Santorini boat trip, Eleonora’s falcons are birds to know. They are away from their nesting sites between November and March. Their colonies normally hold 10 to 300 pairs.
Their nests normally sit 20 to 50 m apart, but the closest sit only 2 m apart. The lowest are about 5 m above the sea, and others are more than 100 m up.
During a Santorini boat trip, the peregrine falcon is another bird to know. It can see light flicker up to 129 Hz, much faster than mammals can. Hz counts flickers each second.
Young peregrines leave the nest 42 to 46 days after hatching. The highest dive speed reliably measured is 184 km/h. The Mediterranean peregrine, a local type named brookei, is also called the Maltese falcon.
- Rock dove: It is pale grey, with two black bars on each wing and a white lower back.
- Alpine swift: Tagged alpine swifts stayed in the air for more than 200 days in a row.
- European shag: The European shag’s wingspan, the width of its open wings, is 95 to 110 cm.
The Mediterranean storm petrel is a separate local type called melitensis. Its main homes are Filfla, Sicily and the Balearic Islands.
Why is the Aegean so salty on a Santorini boat trip?
A Santorini boat trip happens on salty seawater. Salinity means grams of salt in each kilogram of water, the same as parts per thousand. The World Ocean holds 3.40–3.60% salt. Modern sea salt production sits almost entirely in Mediterranean and other warm, dry climates.
On a Santorini boat trip, the sea feels salty. Water at the bottom of the Sea of Marmara averages about 38 parts per thousand. That is similar to the Mediterranean Sea.
The surface water of the Sea of Marmara averages about 22 parts per thousand. That is only about two-thirds of the level in a typical ocean. The Black Sea holds 1.30–2.30% salt.
On a Santorini boat trip, salt level depends on weather. The Red Sea is the saltiest open sea. It has high evaporation, meaning water dries into the air, and low rainfall.
Without water from the Atlantic, the sea level of the Mediterranean falls about 1 m per year. Water stays in the Mediterranean for about 100 years. This time is called residence time.
- Main salts: Chloride makes up 55% of sea salt by mass, and sodium makes up 30.6%.
- Other salts: Sulfate makes up 7.7% of sea salt by mass, magnesium 3.7%, calcium 1.2% and potassium 1.1%.
- River water: Bicarbonate makes up 48% of dissolved solids in river water but only 0.14% in seawater.
Ocean salt level has been stable for billions of years. Chemical and tectonic processes seem to remove as much salt as is added.
What do knots and nautical miles mean on a Santorini boat trip?
A Santorini boat trip is a sea journey, so its distances use nautical miles. On a sphere with a radius of 6371 km, one degree of latitude is 111.2 km. That is 60.0 nautical miles. Knots began as equal marks on a log-line.
On a Santorini boat trip, knots have an old story. Early log-lines had no knots on them at all. Equal marks came once the nautical mile became a sea standard in the 15th century.
A chip log was a quarter circle of wood. Its radius was 5 or 6 inches and it was 0.5 inch thick. A strong tug freed one or two of its three bridle lines.
On a Santorini boat trip, nautical miles can be measured on a chart. The tools are dividers and the latitude scales at the chart’s sides. The nautical mile has no single symbol.
ICAO uses NM, IEEE uses nmi, and the International Hydrographic Organization uses M. Ships carried sandglasses of 28 seconds and of 14 seconds. A brass tobacco box held tables that turned timings into speeds.
- Fira: A hazard study places Fira 3.5 km to the east-northeast of Nea Kameni.
- Athinios: The same study puts the ferry harbour Athinios 3.5 km southeast of Nea Kameni.
- Oia: The same study puts Thirasia 5.5 km north-west of Nea Kameni and Oia 6.5 km north-north-west.
Dead reckoning is a way of tracking a ship by speed and course. The phrase is recorded as early as 1613.
Which lighthouses light the coast of a Santorini boat trip?
A Santorini boat trip happens in the Cyclades, which form area 8 of the Greek list of lights. Lighthouses mark dangerous coastlines, shoals and reefs, and the safe entries to harbours. Each light has its own colour, flash pattern and timing.
On a Santorini boat trip, the Cyclades are the setting. Greek lights are sorted into 10 areas. The Hellenic Navy Hydrographic Service publishes a List of Lights with the Navy Lighthouse Authority.
Greek lighthouse history starts with the Homeric epics. These poems tell of fires lit on towers and hilltops to help ships. The name Pharos comes from an island near Alexandria.
For a Santorini boat trip, the Greek network has a long story. The bulk of Greek lighthouses were built between 1822 and 1910. Until 1887, sites were picked after requests from locals and sailors.
In 1822 Augustin Fresnel’s lens cut the lamp’s light loss to 17%, where old mirror systems lost 87%. In 1825 Henry Lepaute built a clockwork driven by a weight that turned the lens.
- Akrotiri: The lamp sits 100 m above the sea, but its stone tower is 10 m tall.
- Katapola: A small beacon above the retired Amorgos lighthouse flashes white twice every 10 seconds.
- Acetylene lights: They worked in Greece from 1915 to 2002 and needed new gas only once a year.
The Gaidaros light near Syros had the first rotating lamp in Greece. It used three Argand oil lamps on each of four sides.
Where does the name Santorini come from?
A Santorini boat trip sails around an island with a long history of names. Herodotus says the island was once called Calliste. The name Santorini comes from Saint Irene. She was one of three sisters who died for their faith in 304 AD.
On a Santorini boat trip, the older name Calliste is part of the story. Herodotus says Cadmus, sailing in search of Europe, landed on the island then called Calliste. Cadmus left Phoenicians on the island.
Theras was the son of Autesion and the brother of Argeia, the wife of Aristodemus. Herodotus says Theras left Sparta because he did not want to live under the rule of others.
During a Santorini boat trip, the arrival of Theras is part of the story. Theras did not plan to drive out the old inhabitants, because he saw them as his near kin.
In 303, Emperor Diocletian made owning Christian holy books a crime punished by death. Irene, the youngest, was left on a mountain and died of an arrow wound in the throat.
- Feast day: The feast falls on April 3 in Western churches and April 16 in Eastern churches.
- First lord: Iacopo II Barozzi, a Venetian nobleman who died in 1308, was the first lord of Santorini.
- Church region: The Catholic church region of Santorini has the Latin name Dioecesis Sanctoriensis.
Grinus was a king of Thera and a descendant of Theras. The Delphi oracle first told him to found a city in Libya.
What do visitors ask about a Santorini boat trip?
A Santorini boat trip raises questions about glare, jellyfish stings, wet ears, and food safety. Polarized lenses make objects look sharper. Drying the ears very well helps prevent swimmer’s ear. After 4 hours in the danger zone, perishable food is thrown out.
How does glare from the water matter on a Santorini boat trip?
Glare happens when light bounces off a smooth surface, such as calm water. That light goes straight into the eyes. A polarized filter acts like a miniblind, so only light through the slats gets in. Objects look sharper.
Why does VHF channel 16 matter on a Santorini boat trip?
Coast guards in lots of places monitor VHF channel 16, a radio channel, twenty-four hours a day. After the first reply on channel 16, a call must switch to a working channel. That keeps channel 16 free.
What does the NHS say about a jellyfish sting on a Santorini boat trip?
The NHS says not to pee on a sting from a jellyfish or another sea creature. It also says not to put ice or a cold pack on the sting. Bare hands must not touch tentacles or spines.
How is swimmer’s ear linked to a Santorini boat trip?
Medical advice for swimmer’s ear is to dry the ears very well. Ear, nose and throat doctors say a half-alcohol, half-vinegar mix makes eardrops that evaporate water. This works only if the eardrum has no hole.
What does a waterproof rating mean for a phone on a Santorini boat trip?
For an IPX8 rating, the maker sets the test depth and time. The depth is normally up to 3 metres. The IP code standard aims to give more detail than vague marketing words such as waterproof.
How does heat affect food on a Santorini boat trip?
The temperature danger zone runs from 5 °C to 60 °C. Food poisoning bacteria can grow to unsafe levels in that range. In the right conditions, bacteria in food can double in number every 20 minutes.