HOME

TheInfoList



OR:

The Pentland Firth ( gd, An Caol Arcach, meaning the Orcadian Strait) is a
strait A strait is an oceanic landform connecting two seas or two other large areas of water. The surface water generally flows at the same elevation on both sides and through the strait in either direction. Most commonly, it is a narrow ocean chan ...
which separates the Orkney Islands from Caithness in the north of
Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to ...
. Despite the name, it is not a
firth Firth is a word in the English and Scots languages used to denote various coastal waters in the United Kingdom, predominantly within Scotland. In the Northern Isles, it more usually refers to a smaller inlet. It is linguistically cognate to ''f ...
.


Etymology

The name is presumed to be a corruption of the
Old Norse Old Norse, Old Nordic, or Old Scandinavian, is a stage of development of North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants of Scandinavia and their overseas settlement ...
"Petlandsfjörð", meaning "the fjord of Pictland", and is completely unrelated to the Pentland Hills near
Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...
. Prior to the Norse occupation of Orkney the strait was known as the "Sea of Orcs" – a reference to the Pictish tribe who inhabited Orkney. Such was their marine prowess that there are also instances of this name referring to the sea lanes of the entire west coast of Scotland down to Kintyre. One version of the 9th-century '' Historia Brittonum'' states that "the Britons originally filled the whole island with their peoples from the English Channel to the Sea of Orcs".


Geography

On the Caithness (southern) side the Firth extends from Dunnet Head in the west to Duncansby Head in the east, while on the Orkney (northern) side from Tor Ness on
Hoy Hoy ( sco, Hoy; from Norse , meaning "high island") is an island in Orkney, Scotland, measuring – the second largest in the archipelago, after Mainland. A natural causeway, ''the Ayre'', links the island to the smaller South Walls; the two ...
in the west to Old Head on South Ronaldsay in the east. In the middle of the Firth are two significant islands, Stroma and Swona. The small Pentland Skerries group are in the east. The islands of
Hoy Hoy ( sco, Hoy; from Norse , meaning "high island") is an island in Orkney, Scotland, measuring – the second largest in the archipelago, after Mainland. A natural causeway, ''the Ayre'', links the island to the smaller South Walls; the two ...
and South Ronaldsay border the firth to the north and are part of the Orkney Islands. The most northerly point of the headland of Dunnet Head, Easter Head, is also that of mainland Britain. The famous John o' Groats, Mey (site of the Castle of Mey), and many smaller villages are also to be found on the Caithness side as is the town of Thurso and Scrabster Harbour in
Thurso Bay Thurso Bay, known also as Scrabster Bay, is a bay of Atlantic water between the points of Clairdon Head and Holborn Head on the north coast of Caithness, Scotland. The bay receives fresh water from the River Thurso and the Wolf Burn. The rive ...
, on the western fringe of the Firth.


Crossing the Firth

In the West the ferry from Scrabster to
Stromness Stromness (, non, Straumnes; nrn, Stromnes) is the second-most populous town in Orkney, Scotland. It is in the southwestern part of Mainland Orkney. It is a burgh with a parish around the outside with the town of Stromness as its capital. E ...
operated by NorthLink is the oldest continuous ferry service across the firth by the ferry MV ''Hamnavoe'', started in 1856 as a continuation of the railhead at Thurso. The Far North Line opened 28 July 1874 Historically the Gills Bay area has been the main setting off point from the mainland to the islands of Stroma and Swona and Orkney itself. At present
Pentland Ferries Pentland Ferries is a privately owned, family company which has operated a ferry service between Gills Bay in Caithness, Scotland and St Margaret's Hope on South Ronaldsay in Orkney since May 2001. The company is one of only two major vehi ...
operate on this route from Gills Bay to
St Margaret's Hope St Margaret's Hope is a village in the Orkney Islands, off the north coast of Scotland. It is known locally as "The Hope" or "The Hup". With a population of about 550, it is Orkney's third largest settlement after Kirkwall and Stromness. St ...
on South Ronaldsay. At the eastern end John o' Groats Ferries sail to Burwick, also on South Ronaldsay. This is a small passenger ferry and is run in the summer months only. Consideration was also given to construction of a tunnel linking the islands to the mainland. The tunnel was initially projected to have cost £100 million based on preliminary studies carried out in 2005 but as of 2012 no further progress has been made. The first recorded swim across the Pentland Firth was by Coleen Blair in 2011. It has since been swum by others including Andrea Gellan (2011; fastest swim) Mark Cameron (2018) and Alison Lievesley (2020)


Tidal races

The Firth is well known for the strength of its tidal currents, which are among the fastest in the world, a speed of being reported close west of Pentland Skerries. The force of the tides gives rise to overfalls and
tidal race Tidal race or tidal rapid is a natural occurrence whereby a fast-moving tide passes through a constriction, resulting in the formation of waves, eddies and hazardous currents. The constriction can be a passage where the sides narrow, for example ...
s which can occur at different stages of the tide. Combined with gale-force winds, they often give rise to extremely violent sea conditions, which have caused accidents such as the 2015 sinking of the cargo ship MV Cemfjord that resulted in the death of eight crew members. Some of the principal tidal races are: *‘The Merry Men of Mey’. Forms off St John's point in the west-going stream and extends as the tide increases NNW across the firth to Tor Ness. The worst part is over a sand wave field about west of Stroma. The waves formed by this race form a natural breakwater with relatively calm water to the east of it, particularly noticeable when a westerly swell is running. Tides in this area can exceed . *‘The Swelkie’. The race at the north end of Stroma, off Swelkie Point is known as "The Swelkie". It extends from the point in an easterly or westerly direction depending on the tide and can be particularly violent. The whirlpool, according to a nordic tradition recorded in the Eddas, is caused by two gýgjar named Fenja and Menja turning the millstone Grótti, which grinds out the ocean's salt. The witches 'Grotti Finnie' and 'Grotti Minnie' feature in later
Orcadian Orcadians, also known as Orkneymen, are an ethnic group native to the Orkney Islands, who speak an Orcadian dialect of the Scots language, a West Germanic language, and share a common history, culture and ancestry. Speaking Norn, a native North G ...
and Shetlandic folklore. The name of the race is derived from non, Svalga, meaning "the Swallower". *The ‘Duncansby Race’ forms off Ness of Duncansby at the start of the SE-going tidal stream (flood). Initially extending ENE but wheeling gradually anti-clockwise until it extends about NW some  h later at which point it is known as ‘The Boars of Duncansby’. During the time of the SE stream there is additional turbulence off Duncansby Head, particularly to the East. The race temporarily ceases at the turn of the tide before forming in an ENE direction in the NW-going tidal stream (ebb) before ceasing again at the next turn of the tide. The race is particularly violent and dangerous when the tidal stream is opposed by gales in the opposite direction. During the east-going stream a race forms off Ness of Huna. This race can be particularly violent in an easterly or southeasterly gale. *The ‘Liddel Eddy’ forms between South Ronaldsay and Muckle Skerry in the East-going stream (flood). A race also forms for part of the time off Old Head at the SE part of South Ronaldsay. In addition to ‘The Swelkie’, races form at both the north and south ends of Stroma and Swona. Between the races there is a calm eddy which extends down tide as the tide strengthens. The races are highly visible with overfalls and whirlpools. Large swell waves can also be present, especially in bad weather conditions. When entering or leaving the eddies, crossing the races, even large powerful vessels can be pushed off course, such is the demarcation between the relatively calm eddy and the fast-moving tide in the races. There are other races in the firth particularly off Brough Head.


Tidal power

Currents of up to make the Pentland Firth potentially one of the best sites in the world for
tidal power Tidal power or tidal energy is harnessed by converting energy from tides into useful forms of power, mainly electricity using various methods. Although not yet widely used, tidal energy has the potential for future electricity generation. ...
. This has taken on a political dimension. The SNP Energy Review of July 2006 claimed that the Firth could produce "10 to 20 GW of synchronous electricity" and
First Minister A first minister is any of a variety of leaders of government cabinets. The term literally has the same meaning as "prime minister" but is typically chosen to distinguish the office-holder from a superior prime minister. Currently the title of '' ...
Alex Salmond claimed that the Pentland Firth could be "the Saudi Arabia of tidal power" with an output of "20 gigawatts and more than that". In July 2013 Thomas Adcock of Oxford University stated that the Firth "is almost certainly the best site for tidal stream power in the world" although a peer-reviewed study he led suggested that the maximum potential of the Firth was 1.9 GW of tidal power, with one GW being a more realistic figure. In October 2008 tidal power developer Atlantis Resources Corporation (ARC) announced it was considering a site near the Castle of Mey for a computer data centre that would be powered by a tidal scheme in the Firth. In October 2010
MeyGen MeyGen (full name MeyGen tidal energy project) will be the world's largest tidal energy plant, which is currently in construction. The first phase of the project uses four 1.5MW turbines with rotor diameter turbines submerged on the seabed. The ...
, a consortium of ARC, Morgan Stanley and
International Power Engie Energy International, formerly International Power, is a multinational electricity generation company headquartered in Newcastle upon Tyne, and a wholly owned subsidiary of the French company Engie (formerly GDF Suez). The company was fo ...
, received operational lease from the Crown Estate to a 400  MW project for 25 years.Major Scottish tidal project unveiled
''New Civil Engineer'', 28 October 2010. Retrieved: 4 November 2010.
Consent was granted in September 2013 for MeyGen to build a 9 MW demonstration project of six AR1000 turbines commissioning in 2015 with 86 MW planned for phase 1 by 2020. The second phase would install up to 400 turbines generating 398 MW. MeyGen completed the longest-ever run of continuous tidal electricity generation in 2019 with 25 GWh produced, enough to power nearly 4,000 homes.


Marine wildlife

Seals Seals may refer to: * Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly: ** Earless seal, or "true seal" ** Fur seal * Seal (emblem), a device to impress an emblem, used as a means of a ...
can be seen at all times of the year in all parts of the firth. They usually bask on the rocks on the ebb (falling) tide since it saves them having to move as the water rises. Large groups of seals can be seen at the north of Stroma, from the lighthouse round to the north-west part of the island and at the south end in the area of the beacon and to the east between the old jetty and the lighthouse. On Swona they can be seen around the midpoint of the west coast. The common seal come in various colours with spots and have their pups in May, June and July. They are of a similar colour to the adults and can swim from birth, The
grey seal The grey seal (''Halichoerus grypus'') is found on both shores of the North Atlantic Ocean. In Latin Halichoerus grypus means "hook-nosed sea pig". It is a large seal of the family Phocidae, which are commonly referred to as "true seals" o ...
, which is more common in this area having one of the largest British populations, also comes in a number of colours and live in colonies giving birth to white pups from October through to January. These pups do not swim at first until they shed their white coat. When giving birth seals can often be seen inland. Porpoises can be seen all year round in all parts of the firth although they tend to favour shallower water. They grow to about 1.5 m and are black with a broad based triangular fin which can be seen as they surface. They have a small, rotund body with a short, blunt head, no beak, and a small, triangular dorsal fin. They are usually seen singly or in small numbers although in the autumn many groups may be seen in Gills Bay. When in groups, they tend to swim in a more random fashion than dolphins who swim together. Dolphins are not very common but seen from time to time. Many different types visit the firth and may be seen anywhere at any time. Larger than porpoises, 2–3 m depending on the type, black, with the rear edge of the fin curved back at the top unlike the straight edge of the porpoise. Head has a distinct beak. Often swim alongside the bow of vessels and frolic in the bow waves. Probably more than one usually swimming together in a more synchronised manner, sometimes leaping out of the water. Killer whales are mostly seen around May to July although may be sighted at any time of the year. Usually swim in a pod of a maximum of from six to twelve individuals led by a matriarchal female. Males can grow up to 9 m long and can be about 25% larger than females and juveniles in the pod. They tend to be fairly distinctive due to their size, fin and markings. The male has a very tall, triangular and erect dorsal fin which is sometimes tilted forwards. Juveniles and adult females both have a smaller, sickle-shaped dorsal fin. When surfacing the grey saddle shows up over the black back, behind the dorsal fin. It has a conical-shaped black head, with a distinctive white oval patch above and behind the eye, an indistinct beak, white throat and large paddle-shaped flippers. Minke whales are quite often seen in June and occasionally through to October but also at other times of the year. Tend to feed in the up-welling water of the tidal races but can be seen elsewhere. Usually seen singly but may be in pairs. Grows to 7–8.5 m, black with diagonal white band on flipper and a slender, pointed triangular head. Relatively small dorsal fin curved back at top at rear part of body. Will probably see the long back with small fin to rear breaking the surface although they are known to bow and stern ride the waves of vessels. Basking shark. Rare but being seen more often around May to August. A fish rather than a marine mammal, it spends most of its time cruising on the surface filter feeding. The dorsal fin can be seen moving steadily through the water with the tip of the tail moving from side to side behind it. Usually seen feeding inshore at high tide around here in the Gills Bay, Stroma, area though may be seen in deeper water. Generally around 8 m long, greyish brown to bluish black with pale belly. Seen in northern waters in the summer, southern in winter. Often in groups of three or four. Turtles. Very rarely seen, however, they are occasionally found caught in fishing nets in this area. The leatherback is the most frequently recorded species in UK waters and probably the only one in this area. Grows to about 2.9 m with an elongated black shell spotted with white, which tapers to a blunt spike. Migrates to UK waters from the tropics in the summer to feed on jellyfish. There are four other species less frequently encountered in UK waters where they usually occur as stray juveniles carried by currents from warmer seas.


See also

* Gulf of Corryvreckan *
Renewable energy in Scotland The production of renewable energy in Scotland is a topic that came to the fore in technical, economic, and political terms during the opening years of the 21st century. The natural resource base for renewable energy is high by European, and ...


Notes


References

* Watson, W. J. (1994) ''The Celtic Place-Names of Scotland''. Edinburgh; Birlinn. . First published in Edinburgh; The Royal Celtic Society, 1926.


Further reading


The available power from tidal stream turbines in the Pentland Firth
2013 Paper in Proc. R. Soc. A by Adcock ''et al''


External links

*
Pentland Firth - Tides

Tidal Diagrams
{{Authority control Straits of Scotland Caithness Landforms of Orkney Renewable energy in Scotland Orkneyinga saga places