The _Titanic_ left Southampton on Wednesday, April 10, and after calling
at Cherbourg, proceeded to Queenstown, from which port she sailed on the
afternoon of Thursday, April 11, following what was at that time the
accepted outward-bound route for mail steamers from the Fastnet Light,
off the southwest coast of Ireland, to the Nantucket Shoal light vessel,
off the coast of the United States. It is desirable here to explain that
it has been, since 1899, the practice, by common agreement between the
great North Atlantic steamship companies, to follow lane routes, to be
used by their ships at the different seasons of the year. Speaking
generally, it may be said that the selection of these routes has
hitherto been based on the importance of avoiding as much as possible
the areas where fog and ice are prevalent at certain seasons, without
thereby unduly lengthening the passage across the Atlantic, and also
with the view of keeping the tracks of "outward" and "homeward" bound
mail steamers well clear of one another. A further advantage is that, in
case of a breakdown, vessels are likely to receive timely assistance
from other vessels following the same route. The decisions arrived at by
the steamship companies referred to above have, from time to time, been
communicated to the Hydrographic Office, and the routes have there been
marked on the North Atlantic route charts printed and published by the
Admiralty; and they have also been embodied in the sailing directions.
Before the _Titanic_ disaster the accepted mail steamers outward track
between January 15 and August 14 followed the arc of a great circle
between the Fastnet Light and a point in latitude 42° N. and 47° W.
(sometimes termed the "turning point"), and from thence by Rhumb Line so
as to pass just south of the Nantucket Shoal light vessel, and from this
point on to New York. This track, usually called the outward southern
track, was that followed by the _Titanic_ on her journey.
An examination of the North Atlantic route chart shows that this track
passes about 25 miles south (that is outside) of the edge of the area
marked "field ice between March and July," but from 100 to 300 miles to
the northward (that is inside) of the dotted line on the chart marked,
"Icebergs have been seen within this line in April, May, and June."
That is to say, assuming the areas indicated to be based on the
experience of many years, this track might be taken as passing clear of
field ice under the usual conditions of that time of year, but well
inside the area in which icebergs might be seen.
It is instructive here to remark that had the "turning point" been in
longitude 45° W. and latitude 38° N., that is some 240 miles to the
south-eastward, the total distance of the passage would only have been
increased by about 220 miles, or some 10 hours' steaming for a 22-knot
ship. This is the route which was provisionally decided on by the great
trans-Atlantic companies subsequent to the _Titanic_ disaster.
It must not be supposed that the lane routes referred to had never been
changed before. Owing to the presence of ice in 1903, 1904, and 1905
from about early in April to mid-June or early in July, westward-bound
vessels crossed the meridian of 47° W. in latitude 41° N., that is 60
miles further south than the then accepted track.
The publications known as "Sailing Directions," compiled by the
hydrographic office at the Admiralty, indicate the caution which it is
necessary to use in regions where ice is likely to be found.
The following is an extract from one of these books, named "United
States Pilot (East Coast)," Part I (second edition, 1909, p. 34),
referring to the ocean passages of the large trans-Atlantic mail and
passenger steamers:
To these vessels one of the chief dangers in crossing the Atlantic
lies in the probability of encountering masses of ice, both in the
form of bergs and of extensive fields of solid compact ice,
released at the breaking up of winter in the Arctic regions, and
drifted down by the Labrador current across their direct route. Ice
is more likely to be encountered in this route between April and
August, both months inclusive, than at other times, although
icebergs have been seen at all seasons northward of the parallel of
43° N., but not often so far south after August.
These icebergs are sometimes over 200 feet in height and of
considerable extent. They have been seen as far south as latitude
39° N., to obtain which position they must have crossed the Gulf
Stream impelled by the cold Arctic current underrunning the warm
waters of the Gulf Stream. That this should happen is not to be
wondered at when it is considered that the specific gravity of
fresh-water ice, of which these bergs are composed, is about
seven-eighths that of sea water; so that, however vast the berg may
appear to the eye of the observer, he can in reality see one-eighth
of its bulk, the remaining seven-eighths being submerged and
subject to the deep-water currents of the ocean. The track of an
iceberg is indeed directed mainly by current, so small a portion of
its surface being exposed to the action of the winds that its
course is but slightly retarded or deflected by moderate breezes.
On the Great Bank of Newfoundland bergs are often observed to be
moving south or southeast; those that drift westward of Cape Race
usually pass between Green and St. Pierre Banks.
The route chart of the North Atlantic, No. 2058, shows the limits
within which both field ice and icebergs may be met with, and where
it should be carefully looked out for at all times, but especially
during the spring and summer seasons. From this chart it would
appear that whilst the southern and eastern limits of field ice are
about latitude 42° N., and longitude 45° W., icebergs may be met
with much farther from Newfoundland; in April, May, and June they
have been seen as far South as latitude 39° N. and as far east as
longitude 38° 30´ W."
And again, on page 35:
It is, in fact, impossible to give, within the outer limits named,
any distinct idea of where ice may be expected, and no rule can be
laid down to insure safe navigation, as its position and the
quantity met with differs so greatly in different seasons.
Everything must depend upon the vigilance, caution, and skill with
which a vessel is navigated when crossing the dangerous ice-bearing
regions of the Atlantic Ocean.
Similar warnings as to ice are also given in the "Nova Scotia (Southeast
Coast) and Bay of Fundy Pilot" (sixth edition, 1911), which is also
published by the hydrographic office.
Both the above quoted books were supplied to the master of the _Titanic_
(together with other necessary charts and books) before that ship left
Southampton.
The above extracts show that it is quite incorrect to assume that
icebergs had never been encountered or field ice observed so far south,
at the particular time of year when the _Titanic_ disaster occurred; but
it is true to say that the field ice was certainly at that time farther
south than it has been seen for many years.
It may be useful here to give some definitions of the various forms of
ice to be met with in these latitudes, although there is frequently some
confusion in their use.
An iceberg may be defined as a detached portion of a polar glacier
carried out to sea. The ice of an iceberg formed from a glacier is of
quite fresh water. Only about an eighth of its mass floats above the
surface of sea water.
A "growler" is a colloquial term applied to icebergs of small mass,
which therefore only show a small portion above the surface. It is not
infrequently a berg which has turned over, and is therefore showing what
has been termed "black ice" or, more correctly, dark-blue ice.
Pack ice is the floating ice which covers wide areas of the polar seas,
broken into large pieces, which are driven ("packed") together by wind
and current, so as to form a practically continuous sheet. Such ice is
generally frozen from sea water, and not derived from glaciers.
Field ice is a term usually applied to frozen sea water floating in much
looser form than pack ice.
An icefloe is the term generally applied to the same ice (i.e., field
ice) in a smaller quantity.
A floe berg is a stratified mass of floe ice (i.e., sea-water ice).