Geoscience Reference
In-Depth Information
ships. It was traditionally thought that these giant or rogue waves occurred once every
ten thousand years, but as time went on, the sightings became more frequent.
One event was to change perceptions completely, as it was possible to scientifically
measuretheeventknownasthe'DraupnerWave'.OnNewYear'sDay,1January1995
the Draupner oil rig in the North Sea was hit by a 98ft, giant wave. Minor damage was
recorded on the platform and the rogue wave was measured to a good degree of ac-
curacy. The 'Draupner Wave', despite its immense size of 98ft, was certainly not the
largestwaveeverseen,butitwasthefirstwavewhichwasactually scientifically meas-
ured. It may seem surprising, but, despite the history of seafaring spanning a number of
centuries and countless accounts of giant waves, up until the 'Draupner Wave', not one
had been scientifically measured with correct accuracy. Satellite technology has helped
considerably in studying giant waves and in 2004 scientists using three weeks of radar
data from the European Satellite Agency found ten rogue waves of 82ft or more. In
February2000aBritishoceanographyvesselintheRockallTroughwestoftheFlannan
Isles recorded waves with standard heights of 61ft and individual waves up to 95ft.
Without going into great detail, the scientific study of the waves is broken into six
areas: diffractive focusing, focusing by currents, nonlinear effects (modulationary in-
stability), normal part of the wave programme, wind waves, and thermal expansion.
Broadlyspeaking,roguewavescanbedividedintothreemaingroups:wallsofwater,
'Three Sisters'; and single giant storm waves. It should be mentioned that freak waves
are different to tsunamis. Tsunamis are caused by a mass displacement such as a move-
ment of the ocean floor caused by an earthquake. They move at high speeds and only
become dangerous as they approach the shoreline when the depth of the water becomes
shallower. Tsunamis tend to get more media coverage as they affect large areas of in-
habited coastlines on a regular basis, causing immense damage and loss of life which
is comparatively easy to record and verify. By contrast, giant waves are not so easy to
record as they tend to occur far out to sea and in remote areas usually far from regular
sealanes, although, as has been mentioned, in the case of the
München
and the
Edmund
Fitzgerald,
they also occur regularly on shipping routes.
There is no doubt that a number of lightkeepers who were stationed on Eilean Mor
through the years would have long pondered the fate of their fellow lightkeepers on
15 December 1900. One lightkeeper in particular became totally preoccupied with the
missing lightkeepers to the extent that it became almost an obsession.
Walter Robert Aldebert was born on 27 September 1908, almost eight years after the
tragedy. He became a seaman but applied to join the NLB and was accepted as a super-
numerary lightkeeper on 15 May 1929. He was first posted to Inchkeith for his training
where he spent four months before moving onto Macarthur's Head on 23 September
1929. Shortly after his move there, on 3 October 1929, he was promoted to ALK. He
