The Prince George's enquirer and southern Maryland advertiser. (Upper Marlborough, Md.) 1882-1925, 1898-11-04
THE SPEED OF A SHIP

ii' .'ili al eApEana-
ton VIII therefore probably be of inter
est to many readers. There are So.
veral methods, the commonest and
most ancient being by the use of tbe
log" This instrument consists ot
three parts-the logship, the line and
the marks. The logship is piece OF
wood about half an inch thick and
shaped like a quadrant, with piece OF
lead let in round the circular edge to
make it float perpendicular in the wa
ter. 1t is slung by lines at each an
gle, the three lines being joined tc
gether about two feet from the log
ship. Two OF the lines are securely
fixed to the ship and the other has a
bone peg at the end, which, being
pushed into hole in the ship, tempo
rarily fastens it there.
From the point of juncture of the
three lines a sufficient length is meas
ured, generally about 100 feet, to
take the logship well clear of the ship 5
wash. This is called the 'stray line''
and is marked with a piece of bunting.
From the bunting is measured A. feet
inches, and The line marked here
with piece of leather. Then another
Al feet inches is measured of and
marked with two knots, then another
space the same length, and marked
with three knots, and so on as far as
seven knots. Half way between each
batch of knots one single knot is made.
The log line is then ready for use.
The space between the knots is
found from the simple rule of three
sum: As $500 seconds (number of
seconds in an hour), 90 seconds Qength
of sand-glass), $3.50 feet (number of
feet in nautical mile); length of line
required-which works out to Al feet
) inches.
10 use the log four persons are re-
quired-two men to hold the reel on
which the line is wound; the quarter
master, to hold the glass, and the mid
shipman of the watch, to heave the log.
The last named puts the peg firmly in
logship and then gathers three or four
coils OF line in his hand. sufficient to
admit of the l"gship being thrown well
clear OF the ship. He asks, "Clear
glass, quartermaster 7"
Clear glass, sir y comes the reply,
and overheard go the logship and line,
the reel rapidly revolving. Presently
the mildly feels the piece of bunting
passing through his hand, and the he
gives the order, "Turn.' The quar-
termaster turns the glass and watches
the sand while one "rceler" holds the
reel well over his head, so as to give
the line fair play. When the sand has
run out, "Stop" cries the quarter
master.
The midshipman grasps the line, as
sisted by the other reeler, and looks
for the nearest knot, finding single
one close to his hand. Then the line
is hauled in, and four knots appear,
which signify that the ship is going
four and half knots through the wa
ter. The jerk of the line draws the
peg from the logship, which now floats
on its fiat side and is easily hauled in.
When a ship is going over four knots,
a II second glass is used, and the
speed being double that shown by the
knots on the line.
Another method in use is the patent
log. This is altogether mechanical
and consists of Il long cylinder with
clocI-work inside it and four fins on
the outside. 1t is towed astern of the
ship by line made fast to swivel in
the head of it. As it is dragged
through the water the four fins make
it revolve, actuating the clockwork in
side, which registers on series of di-
ais the number of knots run. This
log has to be hauled in every time one
wants to read it, but there is another
kird where the fan is towed astern and
the dial is fixture in the ship. This
is called Il ''cherub.'
These logs are not always accurate,
and are constantly verified. when near
land by cross bearings-that is, the
bearings Of two well known points are
taken, and the position so obtained is
marked on the chart, the time of obser
vation being noted and the reading ON
the patent log After an interval has
elapsed the position of the ship is again
taken by cross bearings, when the
straight line joining the two places on
the chart will show the direction of the
course stccrcl and its length the dis
tance run. y comparison with the
reading by patent log will give error
of the machine.
To finish here is patent log yarn,
as told by an old messmate. | give if
in his own words 'When in the Gro
codile in the Red Sea, just after taking
the reading one night at o'clock, the
quartermaster reported, Shark Taken
the patent log, sir! | got another
one over at once At $50 next morn
ing we stopped for half an hour. To
amuse the ladies tried for and caught
u shark. On opening him we found