Improvements in Stringers suitable for Shipbuilding.
Year: 1892

page_text: Date of Application, 29th July, 1892
Complete Specification Left, 16th Aug., 1892-Accepted, 15th Oct.. 1892
PROVISIONAL SPECIFICATION.
Improvements in Stringers suitable for Shipbuilding.
We, WILLIAM ROCKLIFFE of 35 South Street, Durham, Engineer, and
EDWARD JOBLING of 59 Hartington Street, Monkwearmouth, Sunderland, Boiler
Smith, both in the County of Durham do hereby declare the nature of this
invention to be as follows:-
This invention relates to improvements in stringers suitable for shipbuilding.
According to the system of construction at present generally in vogue, plain flat
plates and angles are built up to form the stringer.
In this system much labour is entailed in punching holes, cutting and shearing
plates and rivetting same.
Thus a common form of stringer consists of a plate with one or more strengthen-
ing angles rivetted to its inner margin; the outer margin of the plate has to be
punched to allow the frame bars to enter the stringer plate sufficiently far to allow
the stringer to come up to the shell to which it is secured by an angle connecting
the shell and stringer.
Another angle is likewise rivetted to the underside of the stringer which angle is
further rivetted to the frame bars.
Thus arranged a stringer has three rows of rivets in it and it is to simplify this
construction that we have conceived the idea of rolling special iron or steel sections
to form the bars and plates.
Two of these sections are then overlapped and rivetted together so as to form the
web stringer whereby great economy accrues.
The precise forms of the sections may vary but generally they will assume the
forms of flanged bars.
Thus a three flanged bar may be rivetted to a tee or angled bar or an angled bar
may be rivetted to a bar with flanges, so as to substitute one or two rows of rivets
for the three rows at present required.
Dated this 6th day of September 1892.
A. CRAWHALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Stringers suitable for Shipbuilding.
We, WILLIAM ROCKLIFFE, Engineer of 35 South Street, Durham and
EDWARD JOBLING Foreman Caulker of 59 Hartington Street Sunderland, both in
the County of Durham, 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:-
This invention relates to improvements in the construction or manufacture of web
stringers suitable for shipbuilding.
Hitherto a large amount of labour has had to be expended in the manufacture of
these web stringers on account of the method employed in their construction.
Hitherto a web stringer has generally consisted of a flat plate with strengthening
angles or bars rivetted thereto, necessitating both the plate and the bars being holed
and then rivetted together; in such construction much time, material, and labour
must necessarily be absorbed in adjusting lengths, punching, fitting and rivetting up
the several parts of the stringer.
A common form of web stringer is a flat plate; out of that margin or edge which
is to go against the ship's shell, notches are punched for the plate to go past the

page_text: reverse frames into the spaces between the frames; on the inner margin or edges an
angle bar, or more cominonly two angle bars, are rivetted so as to form a double
flange, or in some cases a tee-bar is used for the same purpose.
Between all the frames pieces of angle bar called "shell bars" or "lugs" are
rivetted, one flange to the shell, and the other to the stringer plate; and further
beneath the stringer plate another angle bar is rivetted all fore and aft, one flange
to the stringer plate, and the other flange to each reverse frame.
In this (which is the usual arrangement), three rows of rivet holes are required
to be punched in the stringer plate, and three angle bars have to be punched with
corresponding holes, besides the rivet holes in the shell bars, (see Figure 1.).
By our invention we roll the required sections in rolling mills, whereby we need
not employ more than one or two rows of rivets in the stringer and we dispense with
the greater portion of the adjusting and fitting of the component parts above
described, thus effecting a great economy.
We will describe our invention with reference to the accompanying drawings, in
which
Figures 2, 3, 4 and 5 show sections of rolled iron or steel to form web stringers
suitable for ship building purposes.
In each of these figures, two separately rolled sections a and b are shown rivetted
to each other.
These sections can be readily "cropped," "holed" and rivetted together.
In Figure 1. is shown the mode of construction at present generally in use, with
web plate w, the two facing angles w¹, strengthening bar (connecting stringer with
reverse frames) w2, shell bar or lug w³, w¹ and w' representing respectively the ship's
reverse frame bars, and the shell plating.
In our improved construction we may either rivet the shell angle a¹ to section a
of the improved rolled stringer as shown in dotted lines in Figs. 2 and 3 or we may
increase the width of one flange in a and turn or press it up as shown at a² in Fig. 5,
to form the equivalent of an angle bar.
In the latter case the plate a must have notches punched out for each frame bar
before the flange a² is formed as described, and it is the necessity for these notches
which prohibits the use of a stringer having a rolled flange corresponding to the
turned up flange a².
In Figs. 2 and 3 it will be seen that two rows of rivets are required as compared
with three rows required in the old construction shown in Fig. 1. In Figs. 4 and 5
only one row of rivets is required to form the stringer, Fig. 4 representing a stringer
the component parts of which consist substantially of an angle and a channel bar
rivetted together. The thicknesses of the bars and the widths of flanges may vary
to suit any required circumstances.
In Fig. 4, the angles a will be spaced to form notches for the frames and in this
case the web, corresponding to plate w in Fig. 1, is replaced by flange f of angle a
(Fig. 4) which is made of ample strength to serve its purpose.
All punching of stringer web plate for frame spaces is thus abolished and great
economy effected.
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 :
1. The improvement in web stringers suitable for ship building consisting in the
combination of two rolled iron or steel bars or sections so as to form a stringer
substantially in the manner and for the purposes hercinabove described and illus
trated in Figures 2, 3, 4 and 5 of the accompanying drawings.
Dated this 11th day of August 1892.
A. CRAWHALL CHAPMAN,
Newcastle-on-Tyne, Patent Agent.