Year: 1890

page_text: Date of Application, 12th June, 1890-Accepted, 19th July. 1890

page_text: :
gradual change of the upper deck from an are to a perfect semi-circle by a similar
upward curve of the bottom, and by a corresponding inward curve of each side.
The stern is also made spoon shaped, similarly to the bow, but is provided in
addition with a skeag e, with its lower end in line with the bottom of the boat, and
covered with the metallic plating of the vessel, so as to form part of the hull. This
skeag stands out from a point some distance from the extreme rear end of the bull,
50 as to leave an overhanging portion.
The load line of the vessel is unusually high so that both the bow and the stern
will be very near the surface of the water. This will allow the heavy waves to ride
upon the bow and stern portions.
A rudder d of ordinary construction and form is mounted on the rear end of the
skeag, and is adapted to be operated by appropriate mechanism in the pilot house,
which will presently be described and located.
Within the hull, near the stern thereof, is placed a boiler B and an engine C, of
any appropriate construction, and which are preferably surrounded by the usual coal
bunkers.
The piston rod of the engine C, connects with, and operates, the crank arm of the
shaft D, which carries the propeller E. This propeller may be located entirely at
the rear of the skeag or within an opening therein directly in advance of the rudder d.
In order to exclude water from the interior of the hull, the shaft D is surrounded by
an ordinary packing box. Light is admitted to the engine and boiler room by means
of a suitable done or deadlighty, secured to the upper deck.
Extending up from the top or upper deck, are a number of hollow metallic
turrets F, G and H, which communicate with the interior of the hull. The end
turreis Fand H contain each a stair case or steps, and the smoke stack may pass up
one of these turrets, or up the central turret as shown, so as to protect the same from
the action of the waves.
The cabin is mounted securely on top of these turrets F, G, and H, and is of any
suitable design and construction.
In order that the cabin may be further supported, smaller pipes k, k, are secured
beneath each side thereof, and are arranged as shown.
At the forward part of the cabin is the wheel house J, which contains the steering
wheel for controlling the rudder.
At the bow portion of the hull is an isolated turret k, supporting a small working
deck L, which carries the usual capstan or windlass M, for handling the anchor chains,
towing hawser, &c.
Entrance to the hull for purposes of loading or unloading is had through numerous
hatches cut in the upper deck, and which are closed by means of suitable hatch
plates, securely placed and held in position by means of bolts or other suitable
mechanism.
By means of the construction described above it is able to produce a steam tow boat
capable of carrying large quantities of freight and by which very good speed may be
obtained.
By practically disconnecting the cabin from the hull, it will be always cool
and well ventilated and entirely free from all objectionable odours of machinery,
freight, and bilge water.
Further, by means of the general form of hull adopted, a vessel can be made
peculiarly adapted for a steam tow boat, for the reason that the tendency to pitch and
roll in heavy seas is greatly reduced, and the propeller will be always kept under
water. This can be better understood by reference to figures 4, 5, 6, 7, 8, 9 and 10,
of the drawings, in which X represents the hull of an ordinary towing steamer, such
as are seen on the great lakes of America, and y represents a hull of the design
herein described. In all of these views, 1-2 represents the load water line of each
boat, and O represents the centre of gravity of each boat.
In figure 4, the effect of the sea has been to move the boat X, so as to bury the
bow under water and elevate the stern entirely out of water, and thereby cause the
propeller to race, much to the detriment of the machinery. The boat is therefore

page_text: thrown out of its balance, and the wedge shaped air space o. v. s. is submerged, and
is exerting a powerful pressure upwardly, while the wedge portion o, u, r, is out of
the water and is exercising a powerful downward pressure by its weight. These
two forces working together tend to bring the boat back to its balance, but by reason
of the momentum acquired, and by the help of the action of the sea, the centre of
gravity is passed, the reverse action takes place, and the vessel is thrown in position
seen in figure 5. Here the after air space o, t, u, is submerged and exerts an upward
pressure, the bow portion o, s, q, is elevated and exerts a downward pressure, once
more the boat moves towards its line of balance but by reason of the momentum and
the action of the waves, the centre of gravity is passed and the original position
regained. The oscillating motion of the hull often continues long after the disturbing
influence of the waves has ceased.
From an inspection of Figures 6 and 7, it will be seen that the action of the sea
on boats of this design is entirely differens to the action of the sea on ordinary
vessels. As soon as a wave broaches a vessel of this design, the hull is thrown in the
position shown in Figures 6 or 7, with the bow slightly depressed, and the stern
slightly elevated, or vice versa.
The water meeting with but little resistance, now begins to climb up on the bow
or stern as the case may be, and exerts by its weight a downward force opposing the
upward pressure of the submerged portion which is thus eliminated, by reason of
the opposing force caused by the weight of the water on the submerged portion, and
the hull regains its equilibrium, solely by reason of the much less powerful force
caused by the elevated portion of the hull. There is therefore but little momentum
acquired, and it lias been found by practical experience that the movement of the
hull towards its line of balance is very slight. The oscillating motion of the vessel
after the effect of the waves has ceased is thus almost entirely overcome, while the
oscillating motion of the vessel under the disturbing influence of the waves is greatly
reduced.
It will be apparent, as the load is increased and the water line raised, that the
pitching motions of the hull will be proportionately decreased for the reason that
the downward force caused by the weight of the water, will be sooner brought to bear
in opposition to the upward pressure of the submerged portion.
The extreme movements of an ordinary vessel in rolling when moving at right
angles to the direction of the sea, are shown in Figures 8 and 9. It will be: observed
that the first effect of the sea is to raise up the side, and force the hull obliquely
over so as to assume the position shown in Figure 8. Here an air space o. tu, on one
side is submerged and is exerting an upward pressure and a space o. vs on the other
side is elevated out of the water, and is exerting a downward pressure by reason of
its weight. These two forces working together, therefore tend to roll the boat back
to the line of balance, but by reason of the effect of the waves the momentum acquired,
and the masts and the superstructure overhanging the centre of gravity, the vessel
moves past the line of balance and assumes the position shown in Figure 9. The
reversed motion now takes place, so that the boat continues to oscillate from side
to side, precisely in same manner as when pitching, and on exactly the same
theory.
The movements of the vessel in rolling, however are much greater than when
pitching, from the fact that the width is much less than the length and therefore
offers less resistance to the water in moving, and from the additional fact that there
is a greater space exposed to the action of the wind and waves.
It often happens that an ordinary vessel whose course may lie at right angles with
the direction of the waves, is often compelled to run bow on to the sea by reason of
the excessive rolling, and the liability of waves breaking over the bulwarks and
sinking the vessel, so that much time is not only lost, but the vessel may be carried
many miles out of her original course.
The effect of a side sea on a vessel of this design is entirely different from that
on an ordinary vessel. From an inspection of Figure 10, it will be evident that a
wave in striking a hull of this design from the side, will strike a glancing.blow and

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[will roll up on the rounded top, a portion of the way towards the centre. The first
effect of the sea in striking the vessel, might be to careen the vessel slightly to one
to side, or to move the hull bodily to one side, but any rolling movement of the hull
must necessarily be very slight, by reason of the low curved surface exposed to the
waves thereon. Any rolling movement to one side, which might be caused by the
action of the waves, is immediately counteracted by the weight of a wave on
the curved side of the hull exposed to the seas or waves, and by the friction and
weight of the wave in sliding back.
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. The combination with the hull, having a normally high load line, for the
purpose mentioned, of a propeller and propelling mechanism, substantially as herein
shown and described.
2. An improved steam two boat, consisting of a hull having a curved top, straight
sides, spoon shaped bow and stern like the how but with skeag on lower side; a cabin
supported above the hull on turrets, and a propeller and propelling mechanism,
substantially as herein shown and described.
3. The improvements in the construction of hull for and attachments to steam
tow boats substantially as herein shown and described and for the purpose stated.
On tod
NA ZA
Into A IZ JASO
B. J. B. MILLS.
By Harris & Mills,
23, Southampton Buildings, London, Agents.