IMPROVEMENTS IN SLIPWAYS FOR TRANSPORTING AND RAISING AND LOWERING VESSELS FROM ONE LEVEL TO ANOTHER
Year: 1885

page_text: PROVISIONAL SPECIFICATION.
I JOHN STANDFIELD of Westminster Chambers in the City of Westminster
Civil Engineer do hereby declare the nature of my invention for "IMPROVEMENTS
IN SLIPWAYS FOR TRANSPORTING AND RAISING AND LOWERING VESSELS FROM ONE
LEVEL TO ANOTHER" to be as follows:-
This invention has for its object improvements in slipways for transporting and
raising and lowering vessels from one level to another.
To convey a vessel from one side of a mound to another say from a low level
canal to a high level canal over an intervening bank I employ a slipway with
a carriage having a tank upon it in which the vessel is kept floating whilst in
transit. The ascending vessel is counterbalanced by a descending vessel or by
water contained in a tank.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: I JOHN STANDFIELD, of 6 Westminster Chambers in the City of Westminster
Civil Engineer do hereby declare the nature of my invention for "IMPROVEMENTS
IN SLIPWAYS FOR TRANSPORTING AND RAISING AND LOWERING VESSELS FROM ONE.
LEVEL TO ANOTHER" and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
This invention has for its object improvements in slipways for transporting and
raising and lowering vessels from one level to another.
For the purpose of conveying vessels from one level to another say from a low
level canal to a high level canal or vice versa I employ slipways laid upon the sides
of the intervening bank and I provide carriages to ascend and descend these
slipways. These carriages have tanks upon them in which water is contained and
into which the vessels can enter, there being doors similar to lock gates at the end
of the tank which open to admit the vessel.
The tank carriage on one of the slipways is connected by chains or other gear
with the tank carriage on the other slipway and one tank carriage ascends whilst
the other descends.
When a tank carriage is to receive a vessel it is brought to such a position on the
slipway that the tank forms as it were a continuation of the branch of the cɔnal
from which the vessel is to be received. The doors at the end of the tank and the
similar doors at the end of the canal are then opened-the pressure having first
been equalised on the two sides of the doors by the admission of water, to the
intervening space.
The vessel is then drawn into the tank and the doors are closed.
Then the tank carriage with the vessel within it is moved along the slipway from
one side of the tank to the other from bottom to top or top to bottom until the
tank carriage is brought to coincide with the extremity of the other canal when as
before after equalising the pressure on the two sides of the doors these are opened
and the vessel is floated out.
As before stated whilst one carriage ascends another descends and in most cases
it will be possible to work the apparatus without any other power than the weight
of the descending carriage but in some cases it may be convenient to provide other
lifting gear to aid in the operation.
Both of the tank carriages may be employed to convey vessels, but in some cases
it may be more convenient to employ one of them simply as a counterpoise.
In order that my said invention may be most fully understood and readily
carried into effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a plan of the balancing slipways and Figure 2 shows a sectional
elevation of the same. C C is the high level canal, C₁ C₁ is the low level canal.

page_text: These two tanks are connected by means of a number of chains A A A which
are secured to the sides of the tanks and which pass over a number of pulleys P PP
igidly fixed at the top of the slipway.
These pulleys are provided with powerful brakes.
This slipway may lower one boat and raise another at the same time without the
aid of any mechanical power.
This is accomplished by allowing a sufficient quantity of water to flow into the
tank to be lowered-S to make it slightly heavier than the tank to be raised S¹
when on the brakes being released the tank S will descend and in so doing will
raise the tank S¹ and the boat that it contains.
This method of working can be carried out very readily where a supply of water
can be obtained somewhat above the level of the upper canal. With this supply
the tank is filled above the level of the upper canal. After the descent the extra
water in the tank is run off by the lower canal.
The rise and fall of the tank carriages is somewhat less than the distance between
the upper and lower water levels. Hence when the tank carriage arrives at its
upper position it can receive water from the upper canal and water is admitted to
it until the level in the tank becomes the same as that outside. Similarly the
descending tank carriage stops before the water level in the tank is level with that
in the lower canal; water can then be run out from the tank into the lower canal;
and the water level is in this way equalised inside and outside the tank.
These operations of equalizing the water levels obviously give the preponderance
to the upper tank carriage and it descends as soon as it is permitted to do so.
As before stated when the tanks are in a line with the canals the doors are
opened or withdrawn and the barge in the tank at the bottom can enter the lower
canal and the barge in the tank at the top can enter the upper canal.
Sometimes in place of or in addition to the ropes and chains I use several
hydraulic rams and presses T T on either side. I show four on the right hand side
of the drawing; these are brought by means of a pipe U into communication with
four presses T¹ on the left hand side of the drawing.
These rams and presses are so arranged that as one tank ascends the other must
descend; the descending tank S forces the water out of the presses T through the
communication pipe U into the presses T¹ on the other side thus causing the other
tank S to ascend. In like manner the tank S¹, descending causes the tank S
to ascend.
When the tank S is at the top with sufficient water in it to make it preponderate
over the tank S¹ the cock or valve V is opened and the two groups of presses
brought into communication. This allows the tank S to descend and the tank S¹
to ascend.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. My improvements in slipways consisting in providing the same with tank
carriages into which the vessels can be received and kept afloat during transport
and in connecting the carriages so that one balances another substantially as
described.
2. My improved slipways substantially as described and illustrated by the
annexed drawings.