Savannah morning news. [volume] (Savannah) 1868-1887, 1883-08-23
ELECTRIC PROPULSION.
Successful Trial of an Electrical Launch
on the Thames River



\ launch propelled by electricity was
shown on the Thames on several occasions
last year, and attracted "a good deal of at
tention. 1t was propelled by a screw
driven by Siemens motor and SellOn-
NOlckmar accumulators. To a certain
extent the experiment was successful.
Recently Messrs. Tarrow & Co.. Of the
Isle Of Dogs, took the matter up, and,
working with the Electrical Power and
storage Company, a very handsome
launch has been fitted up, intend
ed for the Vienna Exhibition, with
which many experiments have been made.
Tuesday this little boat made a run from
the Temple pier TO Greenwich in thirty
seven INMATES, with a moderate tide.
Some delay was, moreover, caused by the
propeller fOuling basket-an event we'll
known TO every one who has had any ex-
perience with steam launches on the
Thames. The distance is six miles, so
that, making allowance for the tide it
may be said that a speed of over seven
miles an hour was attained, and full
power was not employed, save for por-
ton OF the time. On the measured mile
an average speed of over eight miles an
hour has been obtained.
The boat Is forty feet long and of good
beam. She had twenty-one persons on
board, including the steersman and a man
y
be called. The boat is completely unin-
numbered from end to end, no trace of the
prOpelling mechanism being visible. This
consists of eighty cells of SellOn-N olckmar
accumulatOrs, Of which fourteen are dis
posed under the seat, seven at each side,
and the remainder in the bottom of the
boat. under the floor. The screw is turned
by an a. Siemens' dynamo communicated
as motor. No gearing is used, the
spindle of the armature being cou-
pied direct on to the end of the screw
shaft. The thrust block is Just aft of
the dynamo, which is placed under the
floor IN the stern sheet. 1t lies fiat, and
occupies very little space. There are
four brushes, two for going ahead, two
for going astern, and two small lines going
TO a beckett besides the steersman enable
him at moments notice, by pulling one
or the other, to 90 ahead or astern; cyl
lndrical switch beside him enables him to
stop, or 90 on at pleasure. This switch
is graduated so that the current, from
forty, sixty, or eighty cells, can be used
at pleasure. The weight Of the whole
batteries and dynamO-is about two tons,
or as near as possible that of engine,
boiler with. water. and coal for a steam
engine competent to prOpel her at the
same speed.
This pretty launch is the very perfec-
ton Of pleasure boat; no heat, no
smoke, no dust, no steam, no smell Of oil,
no splashing of pumps. There is no noise
OF any kind to be heard save the bubbling
of the water from the propeller and the
faint his caused by the cOmmutator rub
bing against the brushes. There is no
smell. and no ''black," and the boat will
run for six hours continuously, or about
foTty-five miles.
1t has long been known that the screw
Is an extremely Wasteful propeller. 1t
may yet be that further Investigations
will show that the screw is not so much
to blame as the combination of screw and
engines. At any rate the system of
electrical propulsion opens up new field
of inquiry, because it renders possible the
use of screws of extremely fine pitch re-
volying at a great speed. The dynamo in
Mr.. GarrOW's boat makes about $50 reyO-
buttons per minute. The propeller is of
steel, two bladed, Undetermined diane
ter, and thirteen-nch pitch. There is alb
solutely 10 variation, and very little dis
turbance of the water in the wake of the