AN IMPROVEMENT IN THE CONSTRUCTION OF LIFE-BOATS
Year: 1884

page_text: I HENRY CRITTEN of Cobholm, Great Yarmouth in the County of Norfolk, do
hereby declare the nature of the said invention for "AN IMPROVEMENT IN THE
CONSTRUCTION OF LIFE-BOATS," to be as follows:-
My Invention relates to the construction of the midship air tanks of life-boats
and it has for its object to cause the boat to sail steadier in a gale and when
submerged in a heavy sea to free herself more quickly of water. To accomplish
this I increase the space for water ballast at the bottom of the boat and at same
time increase the air space of the tanks at the upper part so as to act with more
lifting power and diminish the space for water above the level of the water line.
Hitherto the midship tanks of life-boats have been constructed with per-
pendicular or parallel fronts so that the space between the tanks is of equal width
above and below the waterline, but by my Invention I incline or otherwise construct
the fronts so that instead of being parallel they are divergent, or nearer together.
at the upper than at the lower part, thus affording greater space for water between
the air tanks near the bottom of the boat where ballast is required and less at the
upper part above the water line and at same time increasing the air capacity of
the tanks at the upper part where their buoyancy will act with better effect.
Dated this 13th day of March 1884

page_text: I, HENRY CRITTEN, of Cobholm, Great Yarmouth in the County of Norfolk do
hereby declare the nature of my invention for "AN IMPROVEMENT IN THE CON-
STRUCTION OF LIFE BOATS and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
"
My Invention relates to the construction of the midship air tanks of life boats
and it has for its object to cause the boat to sail steadier in a gale and when
submerged in a heavy sea to free herself more quickly of water. To accomplish
this I increase the space for water ballast at the bottom of the boat and at same
time increase the air space of the tanks at the upper part so as to act with more
righting power and diminish the space for water above the level of the water line.
Hitherto the midship tanks of life boats have been constructed with per-
pendicular or parallel fronts so that the space between the tanks is of equal width
above and below the waterline, but by my Invention I incline or otherwise construct
the fronts so that instead of being parallel they are downwardly divergent, or
nearer together at the upper than at the lower part, thus affording greater space
for water between the air tanks near the bottom of the boat where ballast is
required and less at the upper part above the water line and at the same time
increasing the air capacity of the tanks at the upper part where their buoyancy
will act with better effect.
In the accompanying drawings forming part of this specification, I have
represented a mid-ship section of a life boat provided with my improved air tanks
and in dotted lines I have shown the outline of a boat as heretofore constructed,
showing the difference in the form of the air tanks and in the depth of the boat.
A A are the air tanks which instead of being constructed of wood as usual hitherto
are constructed of copper or other sheet metal. As will be seen the tanks are made
somewhat broader at the upper than at the lower part by narrowing the distance
between them to the minimum compatible with the space required by the crew.
It is preferred that the fronts a should be sloped or bevelled but they may be
stepped or curved or of other form so as to secure the same result. By comparing
the sloping fronts shown in full lines and the perpendicular fronts shown in dotted
lines the effect of the alteration in the proportions will be readily understood.
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 :-
The construction of the air tanks of a life boat of greater breadth at the top than
at the bottom substantially as and for the purpose specified.