Audubon County journal. (Exira, Iowa) 1884-1993, 1899-11-02
THE FORCE OF WAVES.
GENTLE ROLLS OF WATER THAT
H.Lo A FEARFUL POWER.


Ground Seas on the English Coast
which Wreck Vessels Calm
Days--TEese S5yclls Strike With n
Force of IL Ton TO the Square Inch.
Many visitors to the coast are sorely
puzzled when a 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 if the
old salt is pushed for a reason he will
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 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 a per-
feclly calm day have been within a
few hours first caught by gentle roll
of the water and finally thrown on
rockbound shore by the dreaded
ground sea-"
To understand this curious marine
phenomenon it must be borne in mind
that out on the Atlantic waves are Of
ten formed to heigh Of 40 feet. Driv-
Ell before heavy gale. these advance
at rate of from 80 to 40 miles an
soon get out of the wind swept
area. But even though, for them, the
storm is past they still roll on in fury,
their undulations often being felt 500
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, unbrosen lines.
perfectly parallel with each other.
Out on the open sea these ridges Of
ten stretch out for a distance of over
so 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
4 sea-"
In this popularity their danger lies,
for when a becalmed ship is caught in
them. her draft, the resisting power
| that enables her to ride out storm,
4 becomes the fulcrum which the liquid
mass uses to hurl her onward to de-
/ struction.
On calm day any sailing craft
caught in the ground sea" near a
rocky shore is as good as lost, unless q
1 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 deceives landsman and warns
a sailor
AS the ground sea- advances it
4 pushes a certain amount of water be
fore it. This also forms into ridges,
like its pursuer, but of less height and
approximately no depth.
! The false sea-" as it is called, is lit.
tie more than a rolling swell, but il
gives a warning of from 20 minutes to
two hours duration, enabling Il ship
to either run into port, get out to sea
or securely anchor; while at the sea,
4 side resorts the boatmen run close in
shore to the surprise of the ''trippers."
When it is remembered that a wave
20 feet high, which is often attained by
the ''ground sea" strikes with force
Of one ton to the square inch, the ne
cessity for caution will be recognized.
All waves that come in parable
ridges, however. are not dangerous, as
there is a wind billow" that is closely
allied to the ground sea- in appear
ance.
wind pillows" are due to a heavy
wind blowing but few miles off the
land. but as they have had but com
paratively short distance to travel they
have no depth. Consequently even {
rowing boat is perfectly safe on then
If properly handled.
These waves usually appear whe1
there Is a comparative calm near tn,
shore, their great point Of Difference.
from the ground sea-" in appearance,
being that their unbroken lines ar,
nearer and are all equidistant. no
travelling in threes.
Generally the wind billow" does no
break into foam, but occasionally thi
happens when they are coming il
against the tide. Then it is hard to de
tect them from ordinary waves. tn
product of a local windstorm. Thes
always break into foam at their crest
the ''white horses Of the marine poe,
Remembering these peculiarities O
the various waves will save tourist
considerable disappointment when wis
er heads bid them keep to the lanG
for. to them. no apparent reason. Will
it may keep them from rushing int
unknown dangers. One other fact
also worthy of mention, as it ma
prove of advantage should boat drift
out to sea with an inexperienced ere,