Improvements in Navigable Vessels.
Year: 1899

page_text: Date of Application, 4th Apr., 1899- Accepted, 13th May, 1899
COMPLETE DITUITIVATION
Improvements in Navigable Vessels.
I, MILLARD FILLMORE MITHOFF, Instructor, of 714, France Street, New Orleans,
in the Parish of Orleans and State of Louisiana, United States of America, do
hereby declare the nature of my 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 certain improvements in the shaping of the hulls of
vessels, the object being to so form the hulls that they will be fully adapted to
the action of the displaced water in the immediate vicinity of the hull when the
vessel is under way, thus reducing the resistance of the movement of the vessel
to a minimum.
This specification is the disclosure of one form of my invention, while the
claims define the actual scope thereof.
Reference is to be had to the accompanying drawings forming a part of this
specification, in which similar characters of reference indicating corresponding
parts in all the views.
Figure 1 is a side elevation of the invention;
Figure 2 is a horizontal section through the line 2-2 of Figure 1, which line
may also be considered the water line.
Figure 3 is a vertical cross section on the line 3-3 of Figure 1;
Figure 4 is a similar view on the line 4-4 of Figure 1.
and
It is known to me by experiments practically conducted, that a solid body
moving through water, will so throw the water, that under the influence of the
propelling action of the moving body and the resistance of the surrounding
stationary water, the water moving away from the body will move in lines each
describing parabolic branches. I have further found that as the said body pro-.
ceeds, the displaced water moves back into the wake of the body in currents
At the
describing the same kind of curves, except that the curves are reversed.
front of said body these currents all move from a central point of focus, which
is established between the resistant force of the water and the propelling force of
the body, and which therefore advances constantly in time with the advance of
the body. The same is true of the action at the rear of the body; that is to say,
the displaced water all returns in distinct currents which move toward a central
point of focus established between the suction of the water at the rear of the body
and the propelling force of the body. Applying this theory to a vessel, it follows
that from the bow of a boat moving ahead, the water in opening moves in lines
describing parabolic branches having a common and constantly advancing focus,
and that the water displaced, closes into the wake at the stern of the vessel in

page_text: currents describing the reverse of the curves described at the bow, all of the stern
currents having in the same way a common and constantly advancing focus.
Now therefore, if the hull of a vessel be constructed with its entrance shaped so
that the exterior lines of all longitudinal sections at or below the water line formed
on planes all passing through a central horizontal axis, will describe parabolic
branches, the origins of which constitute the "cutwater" of the hull, and if the
run be shaped so that each similar section thereof at or below the water line
describes a reversed parabolic branch, the origin of which is at the stern post of
the hull, the vessel, in moving ahead through the water, and in displacing the
water in the manner explained above, will be fully adapted to the action of the
displaced water in moving away from its position of quietude and in returning to
the same.
This central longitudinal axis of the vessel referred to above may be
considered as coincident with the line din Figure 2, and with the point in
Figures 3 and 4, while the lines e in Figures 3 and 4 represent planes in which
sections, if taken, will be bounded by the parabolic branches described. Con-
sequently the form of the hull does not interfere with the natural action of the
water in its displacement and return, and the result is that the vessel progresses
with an entire absence of suction or drag.
The form of the invention shown in the drawings has the hull of the vessel
divided into the entrance a, the run b," and a neutral belt or zone c,' the purpose
of which last is to merge into mechanical regularity the curves of the entrance and
run. Figure 2 being a horizontal section of each side of the hull at the water
line of the vessel, and passing therefore through the central longitudinal axis at
the water line (d in Figure 2 and d in Figures 3 and 4). This figure shows
the side edges of the entrance a describing parabolic branches, the origins of which
are at the ** cut-water" or stem of the vessel, and the ends of which terminate
at the belt c. Figure 2 also shows the run 6 shaped so that, the side edges of the
horizontal section also describe. parabolic branches reversed with respect to those
of the entrance, and having their origins at the stern post of the
vessel and their ends merged into the belt c. This belt is not to be
identified with the parabolic branches of either the run or the entrance, but is
simply a means for merging the ends of the parabolic branches into each other.
It should be understood that other sections taken longitudinally on the line d in
Figure 2 and the point in Figures 3 and 4, but below the water. line, will show
but one side of the hull and not both. All longitudinal sections. taken at any
point below the water line and formed by planes passing through a central
horizontal axis, for example, the line d in Figure 2 and, the point din Figures 3
and 4, will be bounded by parabolic branches, but of course the forms of the
parabolic branches will differ according to the cross sectional model of the hull.
The cross sectional form of the hull below the water line depends on the ratio
of beam to the depth, and must be some segment of a circle, ellipse or parabola.
It may of course have any of these forms consistent with the horizontal section
that may be deemed necessary to the class of vessel constructed.
-
Having now particularly described and ascertained the nature of my
said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. A hull for marine vessels, the hull having an entrance and a run, longi-
tudinal sections of each of which, formed on planes passing through a central
longitudinal axis of the hull, are bounded by parabolic branches, the origins of
which are respectively at the bow and stern of the hull.
2. A hull for marine vessels, having an entrance and a run, longitudinal sections
of each of which, formed by planes passing through a central longitudinal axis
of the hull, are bounded by parabolic branches, the origins of which are respectively
at the bow and stern of the vessel, and the said parabolic branches ending at the
greatest beam of the hull, the hull having at its greatest beam a neutral zone or
'

page_text: belt serving to join the ends of the parabolic branches into a mechanically regular
form.
Dated this 4th day of Anril 1899
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.