Year: 1897

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c. Act, 1883) as allowed by
the decision of the Comptroller General of the 25th day of January 1899.
...
"
I, WILLIAM CASSAP, of 84, Leadenhall Street, in the City of London, Marine
Surveyor and Nautical Expert, do hereby declare the nature of this invention to be as
follows:-
This invention relates to the construction of steain and other navigable vessels, and
consists primarily in an improved form of hull whereby for a given wetted surface
and resistance, increased carrying capacity is obtained, greater strength is imparted
to the structure, and in the case of screw-vessels better immersion afforded to the
propeller when the vessel is in the unloaded or "light" condition.
Assuming my invention to be applied, by way of example, to a steam vessel
intended for cargo-carrying purposes, the rise of floor is preferably somewhat greater
than usual. The midship section is bounded by circular lines described with a
radius of half the extreme beam; the upper ends of. these circular lines terminating
at about the deck-level, whilst their lower ends meet the turn of the bilge.
Such a transverse section, although presenting practically the same wetted surface
as that of a vessel of the usual form, possesses greater strength by reason of the sides
being arch-shaped instead of flat. The scantlings may accordingly be somewhat
modified with corresponding economy in the cost of materials. The carrying capacity
is increased in an important degree, and, owing to the greater rise of floor, the
draught is somewhat greater when the vessel is in the unloaded or "light" condition,
thus affording better immersion of the propeller and facility in handling. For the
same reason, the stability of the vessel when loaded is improved, owing to..the
diminution in the capacity of the ballast tank space; the difference of buoyancy
being compensated for by the rounded and consequently somewhat extended
sides.

page_text: Improvements in the Construction of Steam and other Vessels.
I, WILLIAM CASSAP, of 84, Leadenhall Street, in the City of London, Marine
Surveyor and Nautical Expert, 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 the construction of steam and other navigable vessels, and
consists primarily in an improved form of hull whereby, for a given wetted surface
and resistance, increased carrying capacity is obtained, greater strength is imparted
to the structure, and, in the case of screw-vessels, better immersion is afforded to the
propeller when the vessel is in the unloaded or "light" condition.
The accompanying drawings represent diagrammatically a hull constructed
according to my improved method; Fig. 1 being a mid-section, whereof the left-hand
side is viewed from the .iniddle of the ship looking towards the stern, while the
right-hand side is similarly viewed but looking towards the bows. Fig. 2 is a side
elevation for locating more clearly the various sections indicating the form of the
hull at different points in its length, such sections being ascertained by the corre-
sponding numeral either "aft" or "forward."
Assuming my invention to be applied by way of example to a steam vessel intended
for cargo carrying purposes, the rise of floor, indicated by the line a, is preferably some-
what greater than usual. The midship section is bounded by circular lines bb described
with a radius, from a centre such as c, of half the extreme beam; the upper ends of-the
circular lines terminating at about the deck-level, or reaching nearly to the sheer of
the vessel, while their lower ends meet the turn of the bilge d.
Such a transverse section, although presenting practically the same wetted surface
as that of a vessel of the usual plain sided form, possesses greater strength by reason
of the sides being arch-shaped instead of flat. The scantlings may accordingly be
somewhat modified with corresponding economy in the cost of materials. The
carrying capacity is increased in an important degree, and, owing to the greater rise
of floor, the draught is somewhat greater when the vessel is in the unloaded or "light"
condition, thus affording better immersion of the propeller and facility in handling.
For the same reason, the stability of the vessel when loaded is improved, owing to
the diminution in the capacity of the ballast tank space; the difference of buoyancy
being compensated for by the rounded and consequently somewhat extended sides.
Moreover, in a sea-way, the tendency to rolling is considerably reduced, and the
improved vessel more easily rights herself.
In the example illustrated, some of the supposed measurements of the vessel may
be mentioned for comparison. The length between perpendiculars is 308 feet,
length "over all " 317 feet, breadth, moulded, 46 feet, depth, moulded, 27 feet, rise of
floor, 2.25 feet, the sheer being 3 feet aft and 5 feet forward. The depth to the top
of the beam is 27.85 feet while the breadth across the deck is 40 feet. The dimen-
sions for similar parts in an ordinary plain sided ship would be approximately as
follows: Length between perpendiculars, 308 feet; length "over all", 317 feet;
breadth, moulded, 42.7 feet; depth, moulded, 27 feet; rise of floor, 0.75; sheer,
3 feet aft and 5 feet forward; depth to top of beam, 27.9 feet; breadth across the
deck, 41.7 feet. Although according to the improved mode of construction the vessel
possesses greater breadth of beam as compared with a vessel of the ordinary plain
sided type, Lloyd's numerals for scantlings remain practically the same.
In the improved vessel, the midship deck line is shown at e-e. The load line is
indicated at ff showing the total displacement when loaded 6,654.85 tons. The
water-ballast line is shown at g-y, representing 701-06 tons, giving a displacement
corresponding with a difference of draught of 2 feet 2 inches; h-h indicates the water

page_text: line when the vessel is "empty," the draught being 7 feet 3 inches. The mean draught
of the vessel in ballast is 9 feet 5 inches. In a plain sided ship, with the same deck
level, the water-ballast line would represent a tonnage of 722.9, giving an additional
displacement corresponding with a difference of draught of 2 ft. 3 inches the draught
of the ship when empty being 6 feet 5 inches, with a mean draught in ballast
of 8 feet 8 inches; the total displacement when loaded being 6,635.5 tons.
It will be apparent that the improved method of construction secures various
advantages. For instance, the cargo carrying capacity is increased; whilst, in the
case of screw-steamers, better immersion of the propeller is secured when the vessel
is in ballast.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I claim :-
1
A steam or other vessel, constructed substantially as herein described and charac-
terised by having an increased rise of floor in conjunction with arch-shaped sides
whereof the curves are struck with a radius of half the extreme beam, the upper ends
of the ares approaching the sheer or deck of the vessel whilst their lower ends meet
the turn of the bilge.