ghing 420 lb each, may be
fastened to the carrier, the extra rope called for is obtained by
slipping the upper strand from the drum; this increases the speed of the
upper cable. On the other hand should the distance between the vessels
be reduced, this operation is reversed, the speed of the upper strand
being reduced. To keep the carriage steady on its return empty, a rope,
known as the sea-anchor line, is stretched above the two strands of the
conveyor line, and under a pulley on the carriage. This cable is
attached to the vessel, resting on a saddle on the shear head, whence it
leads through the carriage over pulleys at the head of the foremast and
mainmast of the collier, running on astern several hundred feet into the
sea. A drag or sea-anchor, usually made of canvas and cone-shaped, is
attached to the end of this rope. This anchor is used to support the
empty carriage on its return to the collier. The diameter of the cone's
base is graduated to the speed of the vessels. Thus in a smooth-water
test, with a ship steaming at 6 knots, one 7 ft. in diameter was used,
while the same anchor answered its purpose very well with a ship doing 5
knots in rough water.

The results given by this system of coaling at sea are relatively
satisfactory. Tests made in the United States navy showed that 20 to 25
tons of coal per hour could be delivered by a collier to a war-vessel
during a moderate gale. As the ship was under steam all the time and
consumed 3 to 4 tons of coal per hour, the balance of the coal bunkered
amounted to between 16 and 20 tons per hour, or say 384 tons in 24
hours. It has been suggested that under service conditions the speed of
the towing vessel might be increased to 8 or 10 knots an hour; this
would of course increase the coal consumption unless the collier
proceeded under her own steam. But in such a case the space between the
two crafts might be diminished, which would have the effect of causing
the cable to sag and of stopping the work, since the conveyor cable to
act properly must be kept taut. In Great Britain the Temperley
Transporter Company have taken up this method of coaling at sea, working
in collaboration with Spencer Miller, and have introduced several
improvements in detail. Their system has been tried by the British
admiralty.

The coaling of a large vessel by this appliance has the advantage of
economizing hand labour. One man is required to work the hoist on the
collier, while 20 men wil