Replace Wavetraps on the Midway-Vincent #3 500kV line

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Replace Wavetraps on the Midway-Vincent #3 500kV line


    from the bottom up

    The Marine Institute displayed the Real Map of Ireland featuring the breath taking contoured map of Ireland‟s 220 million acre underwater territory, three dimensional computer model and charts of Irelands Bays and a close look at the history of charting Galway Bay from the bottom up - in a special exhibition on the quayside during the Volvo Ocean Race event.

    The following information was provided by the exhibitors which can be used in class. For further information on the charting of Ireland‟s Bays see


    ; The Real Map of Ireland shows the area of Ireland‟s marine resource which is

    over 220 million acres ten times the area of the land of Ireland.

    ; Historically the oceans of the world were considered to be without boundaries

    and „free‟ to use for travel, trade and exploitation of resources. The Dutch first

    made claim to the area of sea around land in the 1700‟s based on the concept of

    the “three nautical mile” coastal limit. (This was based on the range of land-

    based cannons to fire a cannon ball out to sea). Ever since then, countries have

    laid claim and tried to exert control over parts of oceans that border their shores. ; In the 1960‟s the United Nations Convention on the Law and Sea (UNCLOS)

    established a framework of agreed definitions that gave countries a way to

    establish their claims. This was later established as international law in 1982.

    o Territorial seas 12nautical miles (nm) from the coast.

    o Contiguous zones e.g. customs, immigrations, sanitary controls 24nm

    o Economic Exclusive Zone (EEZ) 200nm

    ; The EEZ gives each country the sovereign right to explore, exploit, conserve and

    manage living and non-living resources in the water and on the seafloor.

    ; The Law of the Sea allows for countries to make claims over shelf areas that go

    beyond 200nm e.g. if they can show that their continental shelf extends beyond

    the established 200nm EEZ.

; The Real Map of Ireland shows the designated Irish Continental Shelf see red

    line on the map.

    ; This area includes one of the largest Exclusive Economic Zones (EEZ) in the

    European Union.

    ; The border of the Irish EEZ extends just beyond what is the „European‟

    continental shelf. The designated Irish Continental Shelf is the area of Irish

    underwater territory which extends beyond the „European‟ continental shelf line

    200 nm from the shore.

    ; The Real Map of Ireland has been developed based on information gathered in

    surveys such as the Irish National Seabed Survey (INSS). This survey began in

    1999 and lasted for six years. It remains one of the largest seabed mapping

    projects ever undertaken in the world.

    ; It has produced over 300+ paper based charts and some 11 Terabytes of digital

    information. If you were to burn this information onto a DVD you would need

    2,421 DVDs.

     Further lesson plans on the Real Map of Ireland are available at


    ; Most nautical charts produced by hydrographic offices worldwide now indicate

    depths of the sea in metres. In the 1800‟s however, nautical charts used feet

    and fathoms (units of six feet) to indicate the depths of the sea.

    ; Until recently, marine charts of Irish coasts had not been updated since the

    1800s, when the task was undertaken by the British where a number of famous

    seamen and hydrographers were involved.

    ; Captain Bligh famous for the “Mutiny on the Bounty” incident and later went on to

    be the Governor of Australia charted Dublin Bay in 1800. The chart was

    completed in 1803 and was considered the most accurate map of the bay well thinto the 20 century.

    ; Admiral Francis Beaufort, born in County Meath was famous for inventing the

    Beaufort Scale in 1806. In 1844 he was responsible for sending Commander

    George Bedford to survey the west cost of Ireland, where he was to remain at

    work for fifteen years.

    ; Based on the surveys done in the 1800‟s and updated with more modern

    information, the present admiralty charts of Irish waters are drawn up by the UK

    Hydrographic Office. They are used today as navigation aids for shipping and

    marine activities. The accuracy and updating of Irish charts and the maps of our

    sea areas, have been debated for years.

    ; When we overlay an enlarged section of a modern bathymetric chart completed

    recently by the INFOMAR survey onto an old Admiralty chart showing Galway

    Bay in the late 1844 - 51 we can see how accurate the old methods of using

    sounding lines and lead lines to gather information were, even though they were

    not exact.

    ; In the 1800‟s to measure the depth of shallow waters, boatmen used a

    OM points. A fathom is a nautical unit of SOUNDING LINE containing FATH

    measurement equal to

    6 feet.

    ; Sailors didn't go around carrying rulers in their back pocket so they used their

    bodies instead to measure distances. For instance, to measure a fathom, a sailor

    would use a line / rope and pull it between his outstretched arms. The distance

    from the tip of the left index finger to the tip of the right index finger was

    approximately one fathom or six feet. (based on a person being six foot).

    Markers using knots / coloured cloth or toggles between each fathom were then

    used to indicate the depth of water.

    ; The well known drawing “The Vitruvian Man” by Leonardo da Vinci, depicts

    historical units of measurement including the Yard, the Foot and the Fathom.

    The distance from tip of nose to tip of an outstretched arm: one yard (three feet)

    Length of human foot: one foot (12 inches).

    ; Water near the coast and not too deep to be fathomed by a hand sounding line

    was referred to as “in soundings” or “on soundings”.

    ; The area offshore where water exceeding 100 fathoms in depth, too deep to be

    fathomed by a hand sounding line, used a deep-sea LEAD LINE, (the heaviest of

    sounding leads).


    ; More recently the Marine Institute, the Geological Survey of Ireland and other research partners have been involved in charting the Irish waters using modern techniques such as using ship-mounted sonar equipment, aircraft-mounted lasers and satellite positioning.

    ; The Marine Institute runs two research vessels on behalf of the State called the RV Celtic Explorer and the RV Celtic Voyager. These vessels, along with other ships

    have been used to survey the Irish waters.

    o The RV Celtic Explorer is used to survey the deep water territory using

    mounted multi-beam sonar equipment.

    o The RV Celtic Voyager and aeroplanes have been used to chart the shallow

    waters and inlets around Ireland using both echo sounders (multi-beam)

    and airborne laser surveying (LiDAR) equipment.

    o The vessels work 24 hours day and night. Staff work in 12 hour shifts.

    ; To find out what is lies beneath the sea a MULTI-BEAM ECHO SOUNDER

    SYSTEM and a LiDAR (Light Detection and Ranging) system are used.

    o The multi beams works similar to how a Bat uses echo‟s to find its way when it

    is flying in the dark. Because Bats are blind they rely on sound waves to find

    their way. The sound waves sent out by the Bat hit the object in front of them

    and bounce back i.e. so they sense trees, mountains and walls. o A Multibeam echosounder works in a similar way. From the bottom of the

    vessel hundreds of sound pulses are sent to the bottom of the seabed in fan

    shaped beams i.e a swath. The multibeams hit the seabed and then are

    transmitted like echo‟s back to the vessel.

    o The width of the swath is determined by the depth of the water. For example if

    the water is deep there is more spread in the swath. If the water is shallow the

    swath width is reduced. Therefore charting the deep sea only took

    approximately just over six years. To complete the inshore areas around

    Ireland is predicted to take up to 20 years.

    o The information which is collected by special equipment on the vessel is then

    processed and worked on to make different types of charts.

    o Other factors have to be taken into account that can affect the overall

    measurements such as tides, temperature, salinity and the pitch and roll of the

    vessel. Note that sound travels at different speeds depending on the

    temperature and salinity of the water. These have to measured and taken into

    account with the processing.

    o LiDAR is a remote sensing technology that uses laser beams of light to

    measure the distance from a LIDAR sensor to distant objects. Its operation is

    similar to how mulitbeam echosounder measures distances underwater using

    sound pulses.

    o A LIDAR sensor, mounted in a plane, is flown over the area to be imaged. The sensor sends out a series of laser pulses toward the Earth's surface. Each laser pulse bounces off objects on its journey toward the ground and returns skyward toward the sensor. The LIDAR sensor measures the time it takes each pulse to travel to the ground or seafloor and back and uses this information to create a 3-D representation of the imaged surface


    ; There are a number of different types of maps and charts of the Irish waters that have been produced from the surveys completed by the Marine Institute, GSI, the Department of Communications, Energy and Natural Resources as well as international research partners.

    ; These maps and charts include:

    o Bathymetry Chart shows the depth of the water. The different colours are

    used which are matched to the legend at the side. Contours are also included

    which are lines of equal depth. This is the same as what is done on land

    showing height.

    o Shaded Relief Chart shows the seabed features and structural geology. On

    the charts shadows are used to emphasise the features such as cliffs, banks

    and troughs. Where areas are relatively flat no shadows are shown.

     i.e. refer to Real Map of Ireland

     the names of areas on the Real Map of Ireland include the

    geology of the area e.g. Edoras Bank

     Galway Shaded Relief shows how the features of the limestone

    steps continue under the water.

    o Backscatter Chart shows the strength of the signal that is reflected back to the

    vessel from the seafloor. (To help establish understanding of strength of

    signals use analogy of throwing a ball against a hard floor v soft mattress

    what happens to the ball?)

    - If the seabed is hard rock the signal is comes stronger and is

    shown as a dark shade on the chart.

    - If the seabed is sandy or muddy some of the signal is absorbed.

    Therefore when it bounces back the signal is weaker. The colour

    therefore is lighter.

    - On the Backscatter chart you can also see the tracklines of the

    vessel. Tracklines show how the vessel has to go up and down a

    strip of sea like a lawnmower moves across a lawn.

    - The backscatter charts now also show square areas where

    samples were taken.

o Seabed Classification Charts shows the seabed type. It is similar to the

    Backscatter but includes information using the samples showing the sediment

    type (i.e. the different type of soils e.g. mud, gravel, sand, rock). These charts

    are used to establish habitats in areas. We need to know what is under the sea

    to be able to protect it and use it in a sustainable way.

    ; INFOMAR Current national coverage:

    o 26 Bays are being surveyed

    o There are also three priority areas including south west priority / south priority

    and east priority. Priority areas have been selected for a combination of

    reasons such as renewable energy, shipping, marine leisure, safety at sea

    and fishing resources, aggregates.

    o Galway Bay was finished last year.

    o This year INFOMAR has did some of Shannon in March. We are now in Dingle

    surveying. During the year we will also be working on Dublin, Waterford /

    Wexford (outer), Bantry block of south priority area, Killary, Donegal, Sligo,

    Lough Foyle.


    ; Multibeam echo sounders can pick up minor variations on the seabed floor such as


    ; (point out on the Real Map of Ireland locations of Shipwrecks of interest that are

    within Irish waters.

    ; The Shipwreck Inventory of Ireland includes all known wrecks up to 1945. There

    are approximately 10,000 records that have been compiled and integrated into the

    shipwreck database.

    o Wrecks over 100 years old and archaeological objects found underwater are

    protected under the National Monuments (Amendment) Acts 1987 and 1994.

    o Significant wrecks less than 100 years old can be designated by Underwater

    Heritage Order on account of their historical, archaeological or artistic

    importance as is the case with the wreck of the Co. Cork RMS Lusitania

    located off Kinsale Head

    o Under the legislation all diving on known protected wreck sites or with the

    intention of searching for archaeological underwater material is subject to

    licensing requirements.

    o allows you to download information about

    shipwrecks in the world including Irish waters.


; RMS Lusitania:

    - The RMS Lusitania was a British ocean liner torpedoed and sunk by the U-boat

    U-20, on 7 May 1915.

    - The ship sank in 18 minutes, eight miles (15 km) off the Old Head of Kinsale,

    Ireland, killing 1,198 of the 1,959 people aboard. The sinking was instrumental

    in bringing the United States into the war.

    - It is considered the second most famous civilian passenger liner disaster, after

    the sinking of the RMS Titanic.

    - The British Government was quick to demonise the Germans for sinking a ship

    carrying civilian passengers, while the German Government claimed that the

    Lusitania was in fact an “armed merchant cruiser” with mountings for guns and

    with a cargo of ammunition, which gave them a legitimate reason to torpedo the

    ship without warning.

; Bismarck:

    - The Bismarck (and her sister ship the Tirpitz) were considered the fastest, most

    powerful battleships afloat in 1941 and Hitler‟s pride and joy.. However after a

    nine day chase, which involved the sinking of England‟s famous battle cruiser

    HMS Hood, the Bismarck sank during combat with the Royal Navy in the North

    Atlantic in May 1941 after having been crippled by a torpedo from an old

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