Shenandoah herald. [volume] (Woodstock, Va.) 1865-1974, 1899-11-17
THEFORCE OF WAVES.
GENTLE ROLLS OF WATER THAT
HOLD A FEARFUL POWER.

Ground Seas on the English Coast
which Wreck Vessels on Calm
Days-These swelIs Strike With n
Force of a Ton to the Square Inch.
Many visitors to the coast are sorely
puzzled when boatman either refuses
to put off from the shore, or at most
go far from land, on day when there
Is no sign Of an approaching storm
and the water is only moved by long
and gentle rolling swell
Argument is Of no avail, and II the
old salt is pushed for a reason he VIII
only reply with some cryptogramic re-
mark about "the ground sea" the
questioner then retiring more bewil-
dered than before.
1t is hard to understand how such
gentle swell can presage danger, but
to experienced eyes IT gives a warning
that must be needed. All along the
west and parts Of the south coasts OF
England and Ireland. as well as the
west coast OF Scotland, uncounted
tales are told OF ships which on per
fectly calm day have been within a
few hours first caught by a gentle roll
Of the water and finally thrown on a
rockbound shore by the dreaded
ground sea-"
To understand this curious marine
phenomenon 1t must be borne In mind
that out on the Atlantic waves are Of
ten formed to heigh Of 40 feet. Driv-
en- before a heavy gale. these advance
at a rate of from 80 to 40 miles an
hour. Travelling at such a rate, they
soon get out OF the wind swept
area. But even though, for them, the
storm Is past they still roll on In fury,
their unduIatiOns often being felt 800
miles from the point Of their creation.
In the region OF the storm these
waves are fierce, breaking pillows, but
as they get farther away they settle
down into long, rolling ridges, which
travel onward In long, unbroken lines,
perfectly parallel with each other.
Out on the open sea these ridges Of
ten stretch out for a distance Of over
30 miles, and they travel In threes,
each successive wave being larger
than its predecessor. The sight is an
imposing one.
The farther they progress the small
er they become in height, but this Is
compensated for by the fact that their
motion is communicated to the mass Of
water below, until the roll can be de.
tected fully 80 feet under the surface.
This gives them the name Of ground
sea-"
In this popularity their danger lies,
for when n becalmed ship Is caught in
them. her draft. the resisting power
that enables her to ride out n storm.
becomes the fulcrum which the liquid
mass uses to hurl her onward to de-
struction.
On a calm day any sailing craft
caught In the ground sea" near n
rocky shore is as good as lost, unless a
wind can spring up and enable her TO
beat out to sea. Many a ship has met
this fate. The reason many more do
not get lost Is due to the gentle swell
that so deceiyes landsman and warns
a sailor.
AS the ground sea" advances II
pushes a certain amount Of water be.
fore 1t. This also forms into ridges,
like It's pursuer, but of less height and
approximately no depth.
The false sea-" as it is called. is lit
tie more than rolling swell. but 1t
gives a warning Of from 20 minutes to
two hours duration. enabling a ship
to either run into port. get out TO sea
or securely anchor; while at the sea-
side resorts the boatmen run close In
shore to the surprise Of the "trlppers.'
When II is remembered that wave
20 feet high. which Is often attained by
the ground sea-" strikes with a force
OF one ton to the square inch. the ne
cessity for caution will be recognized.
All waves that come I'm parallel
ridges. however. are not dangerous. as
there IS wind bilow" that is closely
allied to the ground sea" In appear
ance
wind pillows" are due Ia Il heavy
wind blowing but a few miles Off the
land but as they have had but com
paratively short distance to travel they
have no depth. Consequently even a
rowing boat Is perfectly safe on them
II properly handled.
These waves usually appear when
there is n comparative calm near the
shore, their great point OF difference
from the ground sea-" In appearance
being that their unbroken lines are
nearer and are all eQuidistant, not
travelling In threes.
Generally the wind bIllow" does not
break into foam, but occasionally this
happens when they are coming in
against the tide Then 1t is hard to de-
tect them from ordinary waves, the
product Of a local windstorm. These
always break into foam at their crest,
the white horses" Of the marine poet.
Remembering these pecuiaritles OF
the various waves will save tourists
considerable disappointment when wis
er heads bid them keep TO the land,
for. TO them. no apparent reason. while
II may keep them from rushing into
unknown dangers. One other fact IS
also worthy OF mention. as 1t may
prove Of advantage should a boat drift
out to sea with an inexperienced crew
and no compass aboard.
Then. II "ground sea" Is running"
set your mind at ease. for you can
steer by 1t. as, on the English and
Irish coasts at least. II always comes