THE MOTOR AFLOAT
PLEASURE BOATS--MOTOR LIFEBOATS--MOTOR FISHING BOATS--A MOTOR FIRE
FLOAT--THE MECHANISM OF THE MOTOR BOAT--THE TWO-STROKE MOTOR--MOTOR
BOATS FOR THE NAVY
Having made such conquests on land, and rendered possible aerial feats
which could scarcely have been performed by steam, the explosion motor
further vindicates its versatility by its fine exploits in the water.
At the Paris Exhibition of 1889 Gottlieb Daimler, the inventor who made
the petrol engine commercially valuable as an aid to locomotion, showed
a small gas-driven boat, which by most visitors to the Exhibition was
mistaken for an ordinary steam launch, and attracted little interest.
Not deterred by this want of appreciation, Mr. Daimler continued
to perfect the idea for which, with a prophet's eye, he saw great
possibilities; and soon motor launches became a fairly common sight
on German rivers. They were received with some enthusiasm in the
United States, as being particularly suitable for the inland lakes and
waterways with which that country is so abundantly blessed; but met
with small recognition from the English, who might reasonably have been
expected to take great interest in any new nautical invention. Now,
however, English manufacturers have awaked fully to their error; and
on all sides we see boats built by firms competing for the lead in an
industry which in a few years' time may reach colossal proportions.
[Illustration: A MODERN CAR AND BOAT
In the background is the racing motor boat "Napier II.", which on a
trial trip travelled over the "measured mile" at 30·93 miles per hour.
In the foreground is a "Napier" racing car, which has attained a speed
of 104·8 miles per hour.]
Until quite recently the marine motor was a small affair, developing
only a few horse-power. But because the gas-engine for automobile work
had been so vastly improved in the last decade, it attracted notice
as a rival to steam for driving launches and pleasure boats, and soon
asserted itself as a reliable mover of vessels of considerable size. To
promote the development of the industry, to test the endurance of the
machine, and to show the weak spots of mechanical design, trials and
races were organised on much the same lines as those which have kept
the motor-car so prominently before the public--races in the Solent,
across the Channel, and across the Mediterranean. The speed, as in the
case of cars, has risen very rapidly with the motor boat. When, in
February, 1905, a Napier racer did some trial spins over the measured
mile in the Thames at Long Reach, she attained 28·57 miles per hour on
the first run. On turning, the tide was favourable, and the figures
rose to 30·93 m.p.h., while the third improved on this by over a mile.
Her mean speed was 29·925 m.p.h., or about 2/3 m.p.h. better than the
previous record--standing to the credit of the American _Challenger_.
The latter had, however, the still waters of a lake for her venue, so
that the Napier's performance was actually even more creditable than
the mere figures would seem to imply. At a luncheon which concluded
the trial, Mr. Yarrow, who had built the steel hull, said: "To give an
idea of what an advance the adoption of the internal combustion engine
really represents, I should like to state that, if we were asked to
guarantee the best speed we could with a boat of the size of Napier
II., fitted with the latest form of steam machinery of as reliable a
character as the internal combustion engine in the present boat, we
should not like to name more than sixteen knots. So that it may be
taken that the adoption of the internal combustion engine, in place
of the steam-engine, for a vessel of this size, really represents an
additional speed of ten knots an hour. I should here point out that the
speed of a vessel increases rapidly with its size. For example: in what
is termed a second-class torpedo boat, sixty feet in length, the best
speed we could obtain would be twenty knots; but for a vessel of, say,
200 feet in length, with similar but proportionately larger machinery,
a speed of thirty knots could be obtained. Therefore, the obtaining of
a speed of practically twenty-six knots in the Yarrow-Napier boat, only
forty feet in length, points to the possibility, in the not far-distant
future, of propelling a vessel 220 feet in length at even forty-five
knots per hour. All that remains to be done is to perfect the internal
combustion engine, so as to enable large sizes to be successfully made."
Boats of 300 h.p. and upwards are being built; and the project has
been mooted of holding a transatlantic race, open to motor boats of
all sizes, which should be quite self-contained and able to carry
sufficient fuel to make the passage without taking in fresh supplies.
In view of the perils that would be risked by all but large craft, and
in consideration of the prejudice that motor boats might incur in event
of any fatalities, the Automobile Club of France set its face against
the venture, and it fell through. It is possible, however, that the
scheme may be revived as soon as larger motor boats are afloat, since
the Atlantic has actually been crossed by a craft of 12 h.p., measuring
only forty feet at the water-line. This happened in 1902, when Captain
Newman and his son, a boy twelve years old, started from New York, and
made Falmouth Harbour after thirty days of anxious travel over the
uncertain and sometimes tempestuous ocean. The boat, named the _Abiel
Abbot Low_, carried auxiliary sails of small size, and was not by any
means built for such a voyage. The engine--a two-cylinder--burned
kerosene. Captain Newman received £1,000 from the New York Kerosene
Oil Engine Company for his feat. The money was well earned. Though
provided with proper navigating instruments--which he knew how to
use well--Newman had a hard time of it to keep his craft afloat, his
watches sometimes lasting two days on end when the weather was bad. Yet
the brave pair won through; and probably even more welcome than the
sense of success achieved and the reward gained was the long two-days'
sleep which they were able to get on reaching Falmouth Harbour.
PLEASURE BOATS
We may now consider the pleasure and commercial uses of the motor boat
and marine motor. As a means of recreation a small dinghy driven by a
low-powered engine offers great possibilities. Its cost is low, its
upkeep small, and its handiness very great. Already a number of such
craft are furrowing the surface of the Thames, Seine, Rhine, and
many other rivers in Europe and America. While racing craft are for
the wealthy alone, many individuals of the class known as "the man of
moderate means" do not mind putting down £70 to £100 for a neat boat,
the maintenance of which is not nearly so serious a matter as that of a
small car. Tyre troubles have no counterpart afloat. The marine motor
dispenses with change gears. Water being a much more yielding medium
than Mother Earth, the shocks of starting and stopping are not such
as to strain machinery. Then again, the cooling of the cylinders is
a simple matter with an unlimited amount of water almost washing the
engine. And as the surface of water does not run uphill, a small motor
will show to better advantage on a river than on a road. Thus, a 5 h.p.
car will not conveniently carry more than two people if it is expected
to climb slopes at more than a crawl. Affix a motor of equal power to
a boat which accommodates half a dozen persons, and it will move them
all along at a smart pace as compared with the rate of travel given by
oars. After all, on a river one does not want to travel fast--rather to
avoid the hard labour which rowing undoubtedly does become with a craft
roomy enough to be comfortable for a party.
The marine motor also scores under the heading of adaptability. A
wagonette could not be converted into a motor-car with any success. But
a good-sized row-boat may easily blossom out as a useful self-propelled
boat. You may buy complete apparatus--motor, tanks, screw, batteries,
etc.--for clamping direct on to the stern, and there you are--a
motor boat while you wait! Even more sudden still is the conversion
effected by the Motogodille, which may be described as a motor screw
and rudder in one. The makers are the Buchet Company, a well-known
French firm. "Engine and carburetter, petrol tank, coil, accumulator,
lubricating oil reservoir, exhaust box, propeller shaft, and propeller
with guard are all provided, so that the outfit requires no additional
accessories. For mounting in position at the stern of the boat, the
complete set is balanced on a standard, and carries a steering arm,
on which the tanks are mounted; and also the stern tube and propeller
guard, which are in one solid piece, in addition to the engine. In
order that no balancing feats shall be required of the person in
charge, there is, on the supporting standard, a quadrant, in the
notches of which a lever on the engine frame engages, thus allowing the
rigid framework, and therefore the propeller shaft, to be maintained at
any angle to the vertical without trouble."[12]
The 2 h.p. engine drives a boat 16 feet long by 4 feet 6 inches beam
at 6-1/2 miles per hour through still water. As the Motogodille can be
swerved to right or left on its standard, it acts as a very efficient
rudder, while its action takes no way off the boat.
For people who like an easy life on hot summer days, reclining on
soft cushions, and peeping up through the branches which overhang
picturesque streams, there is the motor punt, which can move in
water so shallow that it would strand even a row-boat. The Oxford
undergraduate of to-morrow will explore the leafy recesses of the
"Cher," not with the long pole laboriously raised and pushed aft, but
by the power of a snug little motor throbbing gently at the stern.
And on the open river we shall see the steam launch replaced by craft
having much better accommodation for passengers, while free from the
dirt and smells which are inseparable from the use of steam-power. The
petrol launch will rival the electric in spaciousness, and the steamer
in its speed and power, size for size.
Some people have an antipathy to this new form of river locomotion on
account of the risks which accompany the presence of petrol. Were a
motor launch to ignite in, say, Boulter's Lock on a summer Sunday, or
at the Henley Regatta, there might indeed be a catastrophe. The same
danger has before now been flaunted in the face of the automobilist
on land; yet cases of the accidental ignition of cars are very, very
rare, and on the water would be more rare still, because the tanks
can be more easily examined for leaks. Still, it behoves every owner
of a launch to keep his eye very widely open for leakage, because any
escaping liquid would create a collection of gas in the bottom of the
boat, from which it could not escape like the gas forming from drops
spilled on the road.
[Illustration:
_Photo Branger & Cie, Paris._
THE MOTOGODILLE
The Motogodille, or Motor Rudder, consists of a screw propeller fitted
to a small Buchet motor. The whole apparatus is mounted on a standard
in the stern, and the operator, by moving the inboard arm to right or
left, can steer the boat as he wishes. A 2-h.p. motor gives a speed of
5 to 6 miles an hour.]
The future popularity of the motor boat is assured. The waterside
dweller will find it invaluable as a means of carrying him to other
parts of the stream. The "longshoreman" will be able to venture much
further out to sea than he could while he depended on muscles or wind
alone, and with much greater certainty of returning up to time. A
whole network of waterways intersects civilised countries--often far
better kept than the roads--offering fresh fields for the tourist
to conquer. River scenery and beautiful scenery more often than not go
together. The car or cycle may be able to follow the course of a stream
from source to mouth; yet this is the exception rather than the rule.
We shoot _over_ the stream in the train or on our machines; note that
it looks picturesque; wonder vaguely whither it flows and whence it
comes; and continue our journey, recking little of the charming sights
to be seen by anyone who would trust himself to the water. Hitherto
the great difficulty has been one of locomotion. In a narrow stream
sailing is generally out of the question; haulage by man or beast
becomes tedious, even if possible; and rowing day after day presupposes
a good physical condition. In the motor boat the holiday maker has
an ideal craft. It occupies little room; can carry fuel sufficient
for long distances; is unwearying; and is economical as regards its
running expenses. We ought not to be surprised, therefore, if in a few
years the jaded business man turns as naturally to a spin or trip on
the rivers and canals of his country as he now turns to his car and
a rush over the dusty highway. Then will begin another era for the
disused canal, the vegetation-choked stream; and our maps will pay more
attention to the paths which Nature has water-worn in the course of the
ages.
To the scientific explorer also the motor affords valuable help. Many
countries, in which roads are practically non-existent, can boast fine
rivers fed by innumerable streams. What fields of adventure, sport, and
science would be open to the possessor of a fast launch on the Amazon,
the Congo, the Mackenzie, or the Orinoco, provided only that he could
occasionally replenish his fuel tanks!
MOTOR LIFEBOATS
Turning to the more serious side of life, we find the marine motor
still much in evidence. On account of its comparatively short existence
it is at present only in the experimental stage in many applications,
and time must pass before its position is fully established. Take,
for instance, the motor lifeboat lately built for the Royal National
Lifeboat Institution. Here are encountered difficulties of a kind very
different from those of a racing craft. A lifeboat is most valuable in
rough weather, which means more or less water often coming aboard. If
the water reached the machinery, troubles with the electrical ignition
apparatus would result. So the motor must be enclosed in a water-tight
compartment. And if so enclosed it must be specially reliable. Also,
since a lifeboat sometimes upsets, the machinery needs to be so
disposed as not to interfere with her self-righting qualities. The list
might easily be extended.
An account of the first motor life-saver will interest readers, so we
once again have recourse to the chief authority on such topics--the
_Motor Boat_--for particulars. The boat selected for experiment was an
old one formerly stationed at Folkestone, measuring thirty-eight feet
long by eight feet beam, pulling twelve oars, double-banked, and of
the usual self-righting type, rigged with jib, fore-lug, and mizzen.
After she had been hauled up in Mr. Guy's yard, where some of the
air-cases under the deck amidships were taken out, a strong mahogany
case, measuring four feet long by three feet wide and as high as the
gunwales, lined with sheet copper so as to be water-tight, with a
close-fitting lid which could be easily removed on shore, was fitted in
place, and the whole of the vital parts of the machinery, comprising
a two-cylinder motor of 10 h.p., together with all the necessary
pumps, carburetter, electric equipment, etc., were fitted inside this
case. The engine drives a three-bladed propeller through a long shaft
with a disconnecting clutch between, so that for starting or stopping
temporarily the screw can be disconnected from the engine. The petrol,
which serves as fuel for the engine, is carried in a metal tank stored
away inside the forward "end" box, where it is beyond any possibility
of accidental damage. Sufficient fuel for a continuous run of over ten
hours is carried. The engine is started by a handle fitted on the fore
side of the case, which can be worked by two men. The position and size
of the engine-case is such that only two oars are interfered with, but
it does not follow that the propelling power of the two displaced men
is entirely lost, because they can double bank some of the other oars
when necessary.
Fitted thus, the lifeboat was tested in all sorts of weather during
the month of April, and it was found that she could be driven fairly
well against a sea by means of the motor alone; but when it was used
to assist the sails the true use of the motor as an auxiliary became
apparent, and the boat would work to windward in a way previously
unattainable. Neither the pitching or rolling in a seaway, in any
weather then obtainable, interfered at all with the proper working or
starting of the motor, which worked steadily and well throughout.
Having been through these preliminary tests, she was more severely
tried. Running over the measured mile with full crew and stores on
board, she developed over six knots an hour. The men were then replaced
by equivalent weights lashed to the thwarts, and she was capsized
by a crane four times, her sails set and the sheets made fast, yet
she righted herself without difficulty. An interesting feature of
the capsize was that the motor stopped automatically when the boat
had partly turned over. This arrangement prevents her from running
away from the crew if they should be pitched out. The motor started
again after a few turns of the handle, so proving that the protecting
compartment had kept the water at bay.
From this account it is obvious that a valuable aid to life-saving
at sea has been found. The steam lifeboat, propelled by a jet of
water squirted out by pumps below the water line, is satisfactory so
long as the boat keeps upright. But in event of an upset the fires
must necessarily be extinguished. No such disability attends the
petrol-driven craft, and we shall be glad to think that the brave
fellows who risk their lives in the cause of humanity will be spared
the intense physical toil which a long row to windward in a heavy sea
entails. The general adoption of this new ally will take time, and must
depend largely on the liberality of subscribers to the fine institution
responsible for lifeboat maintenance; but it is satisfactory to learn
that the Committee has given the boat in question a practical chance in
the open sea by stationing her at Newhaven, Sussex, as a unit in the
lifeboat fleet.
MOTOR FISHING BOATS
It is a pretty sight to watch a fishing fleet enter the harbour with
its catch, taken far away on the waters beyond the horizon while
landsmen slept. The sails, some white, some brown, some wondrously
patched and bearing the visible marks of many a hard fight with the
wind, belly out in graceful lines as the boats slip past the harbour
entrance. No wonder that the painter has so often found subjects for
his canvas and brushes among the toilers of the deep.
But underlying the romance and picturesqueness of the craft there is
stern business. Those boats may be returning with full cargoes, such as
will yield good profits to owner and crew; or, on the other hand, the
hold may be empty, and many honest hearts be heavy at the thought of
wasted days. A few years ago the Yarmouth herring fleet is said to have
returned on one occasion with but a single fish to the credit of the
whole fleet! This might have been a mere figure of speech; it stands,
at any rate, for many thousands of pounds lost by the hardy fishermen.
When the boats have been made fast, the fish, if already disentangled
from the nets, is usually sold at once by auction, the price depending
largely on the individual size and freshness of the "catch." Now, with
the increase in the number of boats and from other causes, the waters
near home have been so well fished over that much longer journeys
must be made to the "grounds" than were formerly necessary. Trawling,
that is, dragging a large bag-net--its mouth kept open by a beam and
weights--along the bottom of the sea for flatfish, has long been
performed by powerful steam vessels, which may any day be seen leaving
or entering Hull or Grimsby in large numbers. Surface fishing, wherein
a long drift-net, weighted at its lower edge and buoyed at the upper
edge to enable it to keep a perpendicular position, is used for herring
and mackerel, and in this industry wind power alone is generally used
by British fishermen.
The herring-boat sets sail for the grounds in the morning, and at
sundown should be at the scene of action. Her nets, aggregating,
perhaps, a mile in length, are then "shot," and the boat drifts along
towing the line behind her. If fish appear, the nets are hauled in soon
after daybreak by the aid of a capstan. The labour of bringing a mile
of nets aboard is very severe--so severe, in fact, that the larger
boats in many cases employ the help of a small steam-engine. During the
return voyage the fish is freed from the meshes, and thrown into the
hold ready for sale as soon as land is reached.
Fish, whether for salting or immediate consumption, should be fresh.
No class of human food seems to deteriorate so quickly when life
is extinct as the "denizens of the deep," so that it is of primary
importance to fishermen that their homeward journey should be performed
in the shortest possible time. If winds are contrary or absent there
may be such delay as to need the liberal use of salt, and even that
useful commodity will not stave off a fall in value.
It therefore often happens that a really fine catch arrives at its
market in a condition which spells heavy loss to the catchers. A slow
return also means missing a day's fishing, which may represent £200 to
£300. For this reason the Dogger Bank fishing fleet is served by steam
tenders, which carry off the catches as they are made, and thus obviate
the necessity for a boat's return to port when its hold is full. Such a
system will not, however, be profitable to boats owned by individuals,
and working within a comparatively short distance of land.
Each boat must depend on its particular powers, the first to return
getting rather better prices than those which come "with the crowd." So
steam power is in some cases installed as an auxiliary to the sails,
though it may entail the outlay of £2,000 as first cost, and a big bill
for upkeep and management. "Small" men cannot afford this expense,
and they would be doomed to watch their richer brethren slip into the
market before them had not the explosion motor come to their aid.
This just meets their case; it is not nearly so expensive to install
as steam, occupies much less room, is easier to handle, and therefore
saves the expense of trained attendants.
Fishermen are notoriously conservative. To them a change from methods
sanctioned by many years of practice is abhorrent. What sufficed for
their fathers, they say, should suffice for them. Their trade is so
uncertain that a bad season would see no return for the cost of the
motor, since, where no fish are caught, it makes little difference
whether the journey to port be quick or slow.
However, the motor is bound to come. It has been applied to fishing
boats with marked success. While the nets are out, the motor is
stopped, and costs not a penny more till the time comes for hauling
in. Then it is geared up with a capstan, and saves the crew much of
their hardest work. When all is aboard, the capstan hands over the
power to the screw, which, together with the sails, propels the vessel
homewards at a smart pace. The skipper is certain of making land in
good time for the market; and he will be ready for the out voyage next
morning. Another point in favour of the motor is that, when storms
blow up, the fleet will be able to run for shelter even if the wind be
adverse; and we should hear less of the sacrifice of life which makes
sad reading after every severe gale.
As to the machinery to be employed, Mr. F. Miller, of Oulton
Broad, who first applied the gas-motor to a fishing smack--the
_Pioneer_--considers that a 12 h.p. engine would suffice as an
auxiliary for small craft of the class found in the northern parts
of Great Britain. The Norfolk boats would require a 30 h.p.; and
a full-powered boat--_i.e._ one that could depend on the motor
entirely--should carry a three-cylinder engine of 80 h.p. In any
case, the machinery must be enclosed and well protected; while the
lubrication arrangements should be such as to be understood easily by
unskilled persons, and absolutely reliable. Owing to the moisture in
the atmosphere the ordinary high-tension coil ignition, such as is used
on most motor-cars, would not prove efficient, and it is therefore
replaced by a low-tension type which makes and breaks the primary
circuit by means of a rocking arm working through the walls of the
cylinder. Lastly, all parts which require occasional examination or
adjustment must be easily accessible, so that they may receive proper
attention at sea, and not send the vessel home a "lame duck" under sail.
The advantages of the motor are so great that the Scotch authorities
have taken the matter up seriously, appointing an expert to make
inquiries. It is therefore quite possible that before many years have
elapsed the motor will play an important part in the task of supplying
our breakfast tables with the dainty sole or toothsome herring.
A MOTOR FIRE FLOAT
As a good instance of this particular adaptation of the explosion
engine to fire-extinction work, we may quote the apparatus now in
attendance on the huge factory of Messrs. Huntley and Palmer, the
famous Reading biscuit makers. The factory lies along the banks of the
river Kennet, which are joined by bridges so close to the water that
a steamer could not pass under them. Messrs. Merryweather accordingly
built the motor float, 32 feet long, 9-1/2 feet beam, and drawing
27 inches. Two engines, each having four cylinders of a total of 30
h.p., drive two sets of three-cylinder "Hatfield" pumps, which give a
continuous feed to the hose. Engines and pumps are mounted on a single
bed-plate, and are worked separately, unless it be found advisable to
"Siamese" the hoses to feed a single 1-1/2-inch jet, which can be flung
to a great height.
One of the most interesting features of the float is the method of
propulsion. As its movements are limited to a few hundred yards, the
fitting of a screw was considered unnecessary, its place being taken by
four jets, two at each end, through which water is forced against the
outside water by the extinguishing pumps. These will move the float
either forward or astern, steer her, or turn her round.
So here once again petrol has trodden upon the toes of Giant Steam: and
very effectively, too.
THE MECHANISM OF THE MOTOR BOAT
In many points the marine motor reproduces the machinery built into
cars. The valve arrangements, governors, design of cylinders and
water-jackets are practically the same. Small boats carry one cylinder
or perhaps two, just as a small car is content with the same number;
but a racing or heavy boat employs four, six, and, in one case at
least, twelve cylinders, which abolish all "dead points" and enable the
screw to work very slowly without engine vibration, as the drive is
continuous.
The large marine motor is designed to run at a slower rate than the
land motor, and its cylinders are, therefore, of greater size. Some
of the cylinders exhibited in the Automobile Show at the London
"Olympia" seemed enormous when compared with those doing duty on even
high-powered cars; being more suggestive of the parts of an electric
lighting plant than of a machine which has to be tucked away in a boat.
Except for the reversing gear, gearing is generally absent on the motor
boat. The chauffeur has not to keep changing his speed lever from one
notch to another according to the nature of the country. On the sea
conditions are more consistently favourable or unfavourable, and, as in
a steamboat, speed is controlled by opening or closing the throttle.
The screw will always be turned by the machinery, but its effect on
the boat must depend on its size and the forces acting in opposition
to it. Since water is yielding, it does not offer a parallel to the
road. Should a car meet a hill too steep for its climbing powers, the
engines must come to rest. The wheel does not slip on the road, and so
long as there is sufficient power it will force the car up the severest
incline; as soon as the power proves too small for the task in hand
the car "lies down." In a motor boat, however, the engine may keep the
screw moving without doing more against wind and tide than prevent
the boat from "advancing backwards." The only way to make the boat
efficient to meet all possible conditions would be to increase the size
or alter the pitch of the screw, and to install more powerful engines.
"Gearing down"--as in a motor-car--being useless, the only mechanism
needed on a motor boat in connection with the transmission of power
from cylinders to screw is the reversing gear.
Though engines have been designed with devices for reversing by means
of the cams operating the valves, the reversal of the screw's movement
is generally effected through gears on the transmission apparatus. The
simplest arrangement, though not the most perfect mechanically, is a
reversible screw, the blades of which can be made to feather this way
or that by the movement of a lever. Sometimes two screws are employed,
with opposite twists, the one doing duty while the other revolves
idly. But for fast and heavy boats a single solid screw with immovable
blades is undoubtedly preferable; its reversal being effected by means
of friction clutches. The inelasticity of the explosion motor renders
it necessary that the change be made gradually, or the kick of the
screw against the motor might cause breakages. The clutch, gradually
engaging with a disc revolved by the propeller shaft, first stops the
antagonistic motion, and then converts it into similar motion. Many
devices have been invented to bring this about, but as a description
of them would not be interesting, we pass on to a consideration of the
fuel used in the motor boat.
Petrol has the upper hand at present, yet heavier oil must eventually
prevail, on account both of its cheapness and of its greater safety.
The only objection to its use is the difficulty attending the starting
of the engine with kerosene; and this is met by using petrol till the
engine and carburetter are hot, and then switching on the petroleum.
When once the carburetter has been warmed by exhaust gases to about
270° Fahrenheit it will work as well with the heavy as with the light
fuel.
Since any oil or spirit may leak from its tanks and cause danger, an
effort has been made to substitute solid for liquid fuel. The substance
selected is naphthalene--well known as a protector of clothes against
moths. At the "Olympia" Automobile Exhibition of 1905 the writer
saw an engine--the Chenier Leon--which had been run with balls of
this chemical, fed to the carburetter through a melting-pot. For a
description of this engine we must once again have recourse to the
_Motor Boat_. The inventors had decided to test its performance with
petrol, paraffin, and naphthalene respectively. "The motor, screwed to
a testing bench, was connected by the usual belt to a dynamo, so that
the power developed under each variety of fuel might be electrically
measured, and was then started up on petrol. As soon as the parts
were sufficiently warmed up by the exhaust heat, the petrol was turned
off, and the motor run for some time on paraffin, until sufficient
naphthalene was thoroughly melted to the consistency of a thick syrup.
The naphthalene was then fed to its mixing valve through a small pipe
dipping into the bottom of the melting-pot, and thence sprayed into the
induction chamber to carburate the air therein. Hitherto, the motor
had given an average of 12 electrical h.p. at 1,000 revolutions per
minute, and it was noticed that as soon as the change was made, this
was fully maintained. This test, when continued, bore out others which
had previously been made by the firm, and showed the consumption of
each of the three fuels to be a little over 12 lbs. per hour for the 12
electrical h.p. given by the motor. Still, the paraffin and naphthalene
worked out about equal as to cost, and considering that the latter was
in its purest form, as sold for a clothes preservative, we have yet to
see how much better its commercial showing will be with lower grades,
assuming beforehand that its thermal efficiency and behaviour are as
good.
"On the ground of convenience naphthalene, as a solid, is a very long
way in front of its liquid rival, kerosene. Its exhaust, too, was
much freer from odour, and it appears that, unlike paraffin, it forms
neither tar, soot, nor sticky matter, but, on the contrary, has a
tendency to brighten all valves, cylinders, walls, etc., any little
deposit being a light powder which would be carried into the exhaust."
THE TWO-STROKE MOTOR
In the ordinary "Otto-cycle" motor an explosion occurs once in every
two revolutions of the crank. With a single cylinder the energy of
the explosion must be stored up in a heavy fly-wheel to carry the
engine through the three other operations of scavenging, sucking in a
fresh charge, and compressing it preparatory to the next explosion.
With two cylinders the fly-wheel can be made lighter, as an explosion
occurs every revolution; and in a four-cylinder engine we might almost
dispense with the wheel altogether, since the drive is continuous, just
as in a double-cylindered steam-engine.
The two-stroke motor, _i.e._ one which makes an explosion for every
revolution, is an attempt to unite the advantages of a two-cylindered
engine of the Otto type with the lightness of a single-cylindered
engine. As it has been largely used for motor boats, especially in
America, a short description of its working may be given here.
In the first place, all moving cylinder valves are done away with,
their functions being performed by openings covered and opened by the
movements of the piston. The crank chamber is quite gas-tight, and
has in it a non-return valve through which vapour is drawn from the
carburetter every time the piston moves away from the centre. There
is also a pipe connecting it with the lower part of the cylinder, but
the other end of this is covered by the piston until it has all but
finished its stroke.
Let us suppose that an explosion has just taken place. The piston
rushes downwards, compressing the gas in the crank chamber to some
extent. When the stroke is three-parts performed a second hole, on
the opposite side of the cylinder from the aperture already referred
to, is uncovered by the piston, and the exploded gases partly escape.
Immediately afterwards the second hole is uncovered also, and the fresh
charge rushes in from the crank case, being deflected upwards by a
plate on the top of the piston, so as to help drive out the exhaust
products. The returning piston covers both holes and compresses the
charge till the moment of explosion, when the process is repeated. It
may be said in favour of this type of engine that it is very simple and
free from vibration; against it that, owing to the imperfect scavenging
of exploded charges, it does not develop so much power as an Otto-cycle
engine of equal cylinder dimensions; also that it is apt to overheat,
while it uses double the amount of electric current.
MOTOR BOATS FOR THE NAVY
A country which, like England, depends on the command of the sea for
its very existence may well keep a sharp eye on any invention that
tends to render that command more certain. In recent years we have
heard a lot said, and read a lot written, about the importance of swift
boats which in war time could be launched against a hostile fleet,
armed with the deadly torpedo. The Russo-Japanese War has given us
a fine example of what can be accomplished by daring men and swift
torpedo craft.
For some reason or other the British Navy has not kept abreast of
France in the number of her torpedo vessels. Reference to official
figures shows that, while our neighbours can boast 280 "hornets," we
have to our credit only 225. In the House of Commons, on August 10th,
1904, Mr. Henry Norman, M.P., asked the Secretary of the Admiralty
whether, in view of the proofs recently afforded of trustworthiness,
speed, simplicity, and comparatively low cost of small vessels
propelled by petrol motors, he would consider the advisability of
testing this class of vessel in His Majesty's Navy. The Secretary
replied that the Admiralty had kept a watch on the recent trials and
meant to make practical tests with motor pinnaces. In view of the
danger that would accompany the storage of petrol on board ship, the
paraffin motor was preferable for naval purposes; and an 80 h.p.
four-cylindered motor of this type has been ordered from Messrs.
Vosper, of Portsmouth.
Mr. Norman, writing in _The World's Work_ on the subject, says: "There
can be no question that such high speed and cheap construction (80 h.p.
giving in the little boat as much speed--to consider that only--as
eight thousand in the big boat) point to the use of motor boats for
naval purposes in the near future. A torpedo boat exists only to
carry one or two torpedoes within launching distance of the enemy.
The smaller and cheaper she can be, and the fewer men she carries,
provided always she be able to face a fairly rough sea, the better. Now
the ordinary steam torpedo boat carries perhaps twenty men, and costs
anything from £50,000 to £100,000. A motor boat of equal or greater
speed could probably be built for £15,000, and would carry a crew of
two men. Six motor boats, therefore, could be built for the cost of
one steamboat, and their total crews would not number so many as the
crew of the one. Moreover, they could all be slung on board a single
vessel, and only set afloat near the scene of action. A prophetic
friend of mine declares that the most dangerous warship of the future
will be a big vessel, unarmoured and only lightly armed, but of the
utmost possible speed, carrying twenty or more motor torpedo boats
slung on davits. She will rely on her greater speed for her own safety,
if attacked; she will approach as near the scene of action as possible,
and will drop all her little boats into the water, and they will make
a simultaneous attack. Their hulls would be clean, their machinery in
perfect order, their crews fresh and full of energy, and it would be
strange if one of the twenty did not strike home. And the destruction
of a battleship or great cruiser at the cost of a score of these little
wasps, manned by two-score men, would be a very fine naval bargain."
Mr. Norman omits one recommendation that must in active service
count heavily in favour of the motor boat, and that is its practical
invisibility in the day or at night time. The destroyer, when
travelling at high speed, betrays its presence by clouds of smoke or
red-hot funnels. The motor boat is entirely free from such dangerous
accompaniments; the exhaust from the cylinders is invisible in every
way. The very absence of funnels must also be in itself a great
advantage. The eye, roving over the waters, might easily "pick up" a
series of stumpy, black objects of hard outline; but the motor boat,
riding low and flatly on the waves, would probably escape notice,
especially when a search-light alone can detect its approach.
It may reasonably be said that the Admiralty knows its own business
best, and that the outsider's opinion is not wanted. The "man in the
street" has become notorious for his paper generalship and strategy,
and fallen somewhat into disrepute as an adviser on military and naval
matters. Yet we must not forget this: that many--we might say most--of
the advances in naval mechanisms, armour, and weapons of defence have
not been evolved by naval men, but by the highly educated and ingenious
civilian who, unblinded by precedent or professional conservatism,
can watch the game even better in some respects than the players
themselves, and see what the next move should be. That move may be
rather unorthodox--like the application of steam to men-o'-war--but
none the less the correct one under the circumstances. We allowed
other nations to lead us in the matter of breech-loading cannon,
armour-plate, submarines, the abolition of combustible material on
warships. Shall we also allow them to get ahead with motor boats, and
begin to consider that there _may_ be something in motor auxiliaries
for the fleet when they are already well supplied? If there is a
country which should above all others lose no time in adding the motor
to her means of defence, that country is Great Britain.
FOOTNOTE:
[12] _The Motor Boat_, March 16th, 1905.