The morning call., 1890-11-23
A NEW SYSTEM
OF PROPULSION
The Next Possible Transforma
ton in Ocean Steamers.
The watsr.Jet Propulsion Considered BY One
Who Has Great Faith in It-safety, Gem
fort, Speed and Economy Claimed.

| XGT1ITH all our advance In design an an,
| QHH2 workmanship we are often painful
NEsNly made aware of defects in ou'
modern screw steamers. One of the mos
| serious is the feebleness of the power tt
stop ship, in many cases the cause of col
lisiOns. Another is the difficulty of prevent
ing, in some weathers. the racing OF the EN-
gines, and thereby causing or leading II
breakdowns sooner or later. Another, and
perhaps the most alarming. is the breaking
| of the main shaft The long shafting OF the
modern screw engine is great source OF
trouble, chiefly from the movements OF the
| hull; so much so that the sbafting may be
said to be always bending. and this is one
of the causes of broken shafts. At all times
| it is source of anxiety. especially in steel
| ships, which yield so readily to strains.
propose to lay before you some OF the
properties of the water-jet propeller, a sys'
TEN of propulsion which promises to remedy
most of the known defects. 1t is not q
novelty | may remark that the mode oil
propulsion of some of the Oldest forms
of marine creatures, the octopus. the cutie
fish and others, is by means OF jet Of
water forcibly discharged The water-le'
| propeller is continuous jet OF water DIS
charged in the opposite direction TO tnat liz
which the ship is required to CO..
In marine propulsion our first o6JectshouldS
be safety secondly, comfort; thirdly, speed
and fourthly, economy. | place safety
| first, as few will dispute the value OF lie
Here we nave propeller, powerful IN
stopping a ship, powerful IN pumping Ou'
water accommodating from LEAK, abe u
steer the ship without rudder,
PROPELLER THAT CANNOT RACE,
One that can put out any fire, aud one thai
| fr,< mi an
| lision, by sudden stoppage and reversal OF
the ships Roadway, is power OF chiei I'M,
portance. This power has been often proved
with the water-jet. With higher speed il
becomes more important Even in 1oggy
weather vessel might safely travel when
the officer could see ships length ahead.
| have seen a ship propelled by tbs water
let brought to rest from full speed in her own
length. The ship can be propelled astern
with the same force as ahead; this Is not
the case with the screw. Great speed with
out the power of stopping quickly is simply
counting disaster.
There have been cases where O ship is
said to have sunk in few minutes after a
hole has been made in her plates. 1t Is quite
possible with the water-jet propeller to ar
range to keep a ship atioat which would
| otherwise sink in five minutes; and not only
aflOat, but to propel her on her voyage.
With tue water-jet propeller the ship can
be navigated in the case OF damaged rud-
der. In the going astem there is no diff
| Guilty, as often occurs with a screw-Ship.
| As regards turning, l have seen ship fitted
with the water-iet turn on her center-that
is, in her own length. The quickest way
and smallest space was by using one lei
ahead and the other neutral. The power to
turn, without going ahead or aStern, is val
liable in some cases.
The movements required to control the
discharge of the jets may be made from the
deck, or from the engine-room. or gear may
be fitted IN both places. The discharge OF
the water, both above and below the water
line has been tried and the effect was
practically the same. Hence rolling aud
pitching will have little or no effect, and
there can be no racing due to the position
of the discharge pipes, relative to the sur.
face of the water. So long as the bottom oil
the ship amidships is in the water, SO long
will the pump draw and send out a con
tinuous stream of water with practically
constant flow, and so have a practically
constant propelliDg effect
IN THE CASE OF FIRE,
One of the chief terrors at sea, the epor
nous quantity of water that can at on
food any part Of the ship must put out any
fire. In the case of instructions to the screw
propeller, of floating wreckage. ropes, tim.
Der or other obstacles, the value of the
water jets stands out in great contrast tt
any propeller having moving. part outside
the ship. With the water-jet propeller
there is no vibration For high speeds thi!
is of great value. not only to the comfort Of
the engineers and passengers, but the life o
the engines and ship will be longer
Regarding speed. there can be no limit ex
cept the power which the ship can carry
There is no heavy stern frame required, 81
that the ship-buiider will have some savin!
in cost and the ship relieved from tht
heavy weights astern. BY taking away thu
screw aperture the ship may be made tina
much shorter. or have greater displacement
with the same fineness of lines aft. Will
regard to the exact economy in smooth
water as propeller, the trials hitherto, IL
some cases, gave results superior to thf
screw; in other cases below the screw. Bu
taking all the evidence on the best authority
! know on this subject, l am convinced thai
in smooth mater the economy of the jet pro-
peler will probably be 80 per cent above the
screw, while in some cases at sea 1t may bt
so per cent above the screw. As SO mucf
success has been attained in the few trial:
already made, i louk for a grand future
both as regards economy and every other adj
vantage claimed or proved.
With regard to the first cost and relativt
weights | am of opinion that the weight.
will be about equal to the screw propeller
that is, the total weights required by thu
I.screw propeller will about equal the dis
placement due TO the water-jet propeller
The ccst will settle itself, and eventually
will be no greater than the screw. Tit
largest power applied to this system was il
! q kuuOudt iUo AOCb iulSy u lOCb OCdius VI
1900 tons displacement, indicated horse
power 750 discharging $50 tons of water PEI
| minute, and the speed was ten knots al
hour. In this case two Jets, each OF two fee
diameter, were used. The size of the dis
charge-tubes has been the subject of great
DIFFERENCE OF OPINION.
One engineer recommended two jets, eact
of five feet diameter, for ship which wa:
successfully driven by two jets of two fee
diameter. Another eXperimenter has gone
to the opposite extreme and proposed very
small jets. AS you know. there is a medi
the extremes will be found the best proper.
ton. For the largest ship would have jets
under two feet diameter, and have mum.
Der of them placed where convenient. The
revolutions Of the pump may be anything
thought best, say from so to go per minute
The screw propeller TODAY has perhaps
reached its limit Of perfection; while, with
all its success, there must still be oppUrtu-
mites for improvements in the water-jet, 81
that its possibilities are greater than we
know OF; II we compare the modes Of &C
tion OF the jet and the screw. we will see
that every particle of water used by the je
is discharged in one direction, while witt
the srrew there is complex action, dis
charging the water radially by centrifugal
force, and many particles driven at variou:
angles from the direction required. With
the jet the centrifugal is used with full
effect, with the screw it is entirely lost
Again, compare the water friction; the
screw has surfaces moving twice the speed
of the surfaces in the water-jet propeller,
this gives four times the loss for the screw
compared with the jet. surface for surface
Again, a weIl-known fact is the increased
resistance of the ship, entirely due 70 the
| screw.
1 believe this Is the first time that the sub.
ject of water-jet propulsion has been laid
before those chiefly concerned. If you ap-
prove or even wish that such an apparatus
may be put into your hands and resolve tf
make it success ia every way, have nc
doubt it will be done. With comparatively
light cranks. no propeller shafting, no tun
mel, no unknown strains, no moving part.
outside the ship, no racing, no vibration, nc
reversing, no easing. no printing and M
breakdowps, look forward to a time wher