An Improved Sounding Apparatus for Indicating Shallows in a Ship's Course.
Year: 1891

page_text: Date of Application, 8th May, 1891-Accepted, 7th May, 1892
An Improved Sounding Apparatus for Indicating Shallows in a
Ship's Course.
We, THEODOR CORNELIUS KNUDSEN and ANTON CHRISTIAN FREDRIK
NORHOLM, both of No. 37 Kjöbmagergade Copenhagen Denmark Mechanicians,
do hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
The object of this invention consists of a self acting apparatus for indicating
approaching shallows in a ship's course.
Figures 1 and 1 and 2 and 2B of the accompanying drawings shew the
apparatus in its entirety applied to a ship in two different ways.
Figures 1 and 2 are side views and Figures 1 and 2 corresponding front
views.
с
The main part of the apparatus is a "lead" a which by means of a line bis
fixed at the stem or fore part of the ship, either as at Figures 14 and 18 at the
keel or as in Figures 2 and 2 at the side or other part (such as the bowsprit)
and thus is made to drag below the keel at a depth depending upon varying
circumstances. A second line e leads from the lead a either through a pipe in the
bottom of the ship as in Figures 1A and 1B, or outside the same as in Figures 24
and 2 to a rollere in a standard or frame; see the enlarged views Figures 3, 4
and 5; this roller e is fixedly connected to a second roller around which a third
line or cord is passed, having at its free end a weight f. The latter is not heavier
than necessary for always stretching the line c tant, and the lead a is made so much
heavier than the weight that the depth to which it depends below the ship is not
altered by the influence of the weight.
The effect produced by the weight fric. to keep the line e taut may however of
course be produced by a helical or other spring either directly connected to the
line e or acting on the roller to which the line c is fixed.
In order that the distance of the lead may not vary according to the speed of the
vessel we give it the form shewn in Figures 6, 7 and 8. Figure 6 is a side view,
Figure 7 an end view and Figure 8 a plan. It is formed as a round disc a, which
as described with reference to Figs. 1 and 2 is held vertically in the water by the
lines and c which are fixed in the holes a . Towards the bottom and back it has
a projection a² the direction of which by preference is made about parallel with
the line through the points of suspension aa of the lines band c. The shape of
these projections at the section lines, y¹y and y2 y2 Fig. 8 is indicated by the
dotted lines in Fig. 6 and the sections on lines and Fig. 6 are shewn in
dotted lines in Fig. 7. During the progress of the ship the water is forced towards
the upper slanting surfaces of these projections so that the lead is prevented from
rising in the water and remains at a depth which will not vary unless the lead goes
against the bottom of the sea.
The standard is shewn with its rollers e and at Figures 3, 4 and 5 in end view
side view and plan.
The spindle m is in some suitable manner connected to an indicator hand that
works against a scale g on the standard and indicates how many feet the lead is
below the keel.
The use of the apparatus will probably be sufficiently understood from the fore-
going. When there is a fear of the ship approaching dangerous shallows the lead a
is dropped so as to drag on the bottom of the sea as shewn in Figures 1 and 2 and
as described. Should the distance between the keel and the bottom become less
than say 24 feet, the lead will by the rising bottom be brought nearer to the keel,
077

page_text: and the counterweight f tighten the line e while the hand indicates the distance on
the scale g. But if there is no fear of shallows being near the spindle m of the
rollers e and i may be turned by a handle put on its square end so that the lead a is
drawn up close to the ship and suitably fixed.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
First. An automatic sounding apparatus for indicating in a ship's course within
certain limits the distance between the keel and the sea bottom, consisting of a lead
which by means of a line is fixedly connected with the ship from which it is also
suspended by a line c, the other end of which is connected with an apparatus fixed
on the ship and which as influenced by the motion of the line e through the rising
or falling of the lead in the water indicates automatically when the distance
between the keel and the sea bottom becomes less than a predetermined amount
substantially as set forth.
Second. In sounding apparatus as firstly claimed the application of a free roller
or pulley e with one end of the lead line e fixed thereto the other end carrying the
lead, in combination with a counteracting weight or spring tending to turn the
roller in the opposite direction so that the line is always kept taut.
Third. The construction of the lead a in the form of a disc which on both sides
downwards and towards the rear is provided with a projection a² having a slanting
surface which is so set that the lead when suspended by the line e during the
forward course of the ship is always depressed influenced by the reactive force of
the water.
Fourth. The construction of the apparatus shewn on the drawings.
Dated this 9th of M... 1001
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.