AN IMPROVEMENT IN THE PROPELLING OF STEAM BOATS
Year: 1858

page_text: LETTERS PATENT to Thomas Britt, of No. 9, St. Thomas Terrace, Church
Street, Old Kent Road, Camberwell, in the County of Surrey, Engineer,
for the Invention of "AN IMPROVEMENT IN THE PROPELLING OF STEAM
BOATS."
Sealed the 25th March 1859, and dated the 30th September 1858.
PROVISIONAL SPECIFICATION left by the said Thomas Britt at the
Office of the Commissioners of Patents, with his Petition, on the
30th September 1858.
I, THOMAS BRITT, of No. 9, St. Thomas Terrace, Church Street, Old Kent
Road, Camberwell, in the County of Surrey, Engineer, do hereby declare
the nature of the said Invention for "AN IMPROVEMENT IN THE PROPELLING OF
STEAM BOATS," to be as follows:-
The principle of my Invention consists of a joint in the boss of the propeller,
and shafting for working the same. By this joint there are four blades
coupled together. The object of this joint in the boss of the propeller, it
allows the propeller to close together, or open out at right angles as may be
required. These blades close together for the convenience of lowering a
propeller down in its place, or hoisting it up on deck. When the propeller is
down in its place, there are apparatus to open them out at right angles, and
the shaft is made to couple them in that position, and work them in that

page_text: position. There are two plans of shafting you can make, which you choose, to
put into work the propeller. This shafting is numbered One and Two.
Number One is one solid shaft, one hollow shaft, and one open shaft.
Number Two is one solid shaft only. Where the two-bladed propellers are
used, the object of this plan is, it doubles the surface acting against the
water. By this Invention, the boat will go faster with less speed to the
engine, whereby a great saving is effected.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Britt in the Great Seal Patent Office on the
26th March 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BRITT, of No. 9, St. Thomas Terrace, Church Street, Old Kent Road, Cam-
berwell, in the County of Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of September, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-second
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Thomas Britt, Her special licence that I, the said
Thomas Britt, my executors, administrators, and assigns, or such others as
I, the said Thomas Britt, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "AN
IMPROVEMENT IN THE PROPELLING OF STEAM BOATS," upon the condition (amongst
others) that I; the said Thomas Britt, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause.
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Britt, do hereby declare the
nature of my said Invention, and in what manner the same is to be. per-
formed, to be particularly described and ascertained in and by the following
statement and accompanying Drawings, that is to say :-

page_text: My Invention consists in the construction of a folding four-blade propeller,
and the shafting for the same; this propeller is formed by four blades. being:
coupled together by a joint in the boss of the propeller; the two principal
blades that have the bearings;, the centre part of the boss is taken out half
way along the boss, sufficient metal in the thick part of the blades to answer
for the centre of the boss being taken out; the other two blades, the boss is
taken out half way along; it goes in the boss of the two principal blades, and
the after bearing is bolted on the two principal blades. The two principal
blades; the fore part of the boss is hollow, the shaft goes through that part
to work the two centre blades; thus the joint is. formed in the boss of the
propeller. The object of this joint in the boss of the propeller is that it
allows the propeller to close together or open out at right angles, as may be
required; these blades close together for the convenience of lowering the
propeller down in its place, or hoisting it up on deck when the propeller is
down in its place. There are apparatus to open them out at right angles, and
the shaft is made to couple them in that position, and work them in that
position.
There are two plans of shafting, which can be made as desired to put in to
work the propeller.
Figure 4, in the accompanying Drawings, represents one solid shaft, one
hollow shaft, and one open shaft; and B, Fig. 3, represents one solid shaft
only, where the common two-blade propellers are used.
The object attained by my Invention is, it doubles the surface acting against
the water, and the boat or vessel will attain a higher speed with less power
from the engine, whereby a great saving is effected.
DESCRIPTION OF DRAWINGS.
Fig. 1, a, a, is a front view of the propeller when it is closed up for the
convenience of lowering it down in its place, or hoisting it up on deck. Fig. 2,
a', a, a, a, is a front view of the propeller representing its working position
when down in its place. Fig. 3, B, is an improved shaft on Fig. 4; c, c, Fig. 4,
being a hollow shaft, while B, Fig. 3, is a solid shaft, which is preferable.
Fig. 4, c¹, c, is a side view of the shafting; and a¹, a', is a view of my
propeller, when down in its place; d is the joint in the boss of the propeller
a', a. I recommend the shaft B, seen in Fig. 3, to be used instead of shaft
c, c, in Fig. 4, to work the propeller.
Having now described the nature of my Invention, and in what manner the
same is to be performed, I declare that what I claim as constituting my said

page_text: Invention, is, a folding four-blade propeller, and the shafting for the same, as
herein-before described.
In witness whereof, I, the said Thomas Britt, have hereunto set my
hand and seal, this Twenty-first day of March, in the year of our
Lord One thousand eight hundred and fifty-nine.
THOMAS BRITT. (L.S.)