U.S. patent application number 16/528449 was filed with the patent office on 2019-11-21 for boat hull.
The applicant listed for this patent is Anthony Little. Invention is credited to Anthony Little.
Application Number | 20190351973 16/528449 |
Document ID | / |
Family ID | 68534165 |
Filed Date | 2019-11-21 |
United States Patent
Application |
20190351973 |
Kind Code |
A1 |
Little; Anthony |
November 21, 2019 |
BOAT HULL
Abstract
A boat hull includes a bow section and a flat aft section to
allow an air film to be introduced under the boat hull. At least
one slot or round hole is arranged proximate a location where the
bow section meets the flat aft section. The slot or round hole
provides a low-pressure injection point for pumped or drawn-in air
and/or exhaust gas, which lubricates an operative surface of the
flat aft section.
Inventors: |
Little; Anthony; (Campbell,
AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Little; Anthony |
Campbell |
|
AU |
|
|
Family ID: |
68534165 |
Appl. No.: |
16/528449 |
Filed: |
July 31, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15579163 |
Dec 1, 2017 |
10399639 |
|
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PCT/AU2015/050308 |
Jun 4, 2015 |
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16528449 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B63B 2001/206 20130101;
B63B 1/22 20130101; B63B 2001/387 20130101; Y02T 70/10 20130101;
B63H 11/00 20130101; B63B 1/063 20130101; B63B 2001/385 20130101;
B63B 2001/201 20130101 |
International
Class: |
B63B 1/06 20060101
B63B001/06 |
Claims
1. A boat hull, comprising a bow section and a flat aft section to
allow an air film to be introduced under the boat hull, wherein:
proximate to a location where the bow section meets the flat aft
section there is provided at least one slot or round hole which
provides a low-pressure injection point for pumped or drawn-in air
and/or exhaust gas, for lubrication of an operative surface of the
flat aft section.
2. The boat hull according to claim 1, wherein the at least one
slot or round hole is rear facing.
3. The boat hull according to claim 1, wherein the at least one
slot or round hole is configured to provide a sufficient pressure
reduction to excite and maintain a venturi effect.
4. The boat hull according to claim 1, further comprising a pump or
blower for distributing the air and/or exhaust gas to the at least
one slot or round hole.
5. The boat hull according to claim 1, comprising secondary
apertures provided further aft of the said at least one slot or
round hole.
6. The boat hull according to claim 1, wherein the air and/or
exhaust gas flows from numerous locations ducted from above the
floatation waterline.
7. The boat hull according to claim 1, further comprising at least
one first pair of generally vertical ribs extending longitudinally
along the underside of the hull towards the stern.
8. The boat hull according to claim 7, further comprising a second
pair of generally vertical ribs, each rib of the second pair of
generally vertical ribs extending downwardly from a corresponding
outboard edge of the hull, a depth of the ribs increasing towards
the stern.
9. The boat hull according to claim 7, wherein the at least one
slot or round hole is provided at a leading edge of a channel
formed between adjacent ribs.
10. The boat hull according to claim 1, further comprising a
plurality of chines extending downwardly from a bow of the hull
towards a stern of the hull, each chine in transverse cross section
being substantially straight and substantially horizontal and
arranged so that a centreline of each chine lies in a plane which
is parallel to a plane extending through a centreline of an
adjacent chine, wherein between each chine is a generally vertical
section, a central chine sits lower and forward of adjacent chines
which are disposed progressively higher and rearward toward sides
of the hull, and an aft portion of a base of the hull is generally
flat and each chine terminates at the flat aft portion to provide a
generally continuous transition from the chine to the flat base of
the hull.
11. The boat hull according to claim 1, further comprising a
plurality of chines extending downwardly from a bow of the hull
towards a stern of the hull, each chine being, at least at a
forward portion thereof, in transverse cross section substantially
straight and inclined toward a central longitudinal plane of the
hull and arranged so that a centreline of each chine lies in a
plane which is parallel to a plane extending through a centreline
of an adjacent chine, wherein a central chine sits lower and
forward of adjacent chines which are disposed progressively higher
and rearward toward sides of the hull, and an aft portion of a base
of the hull is generally flat and each chine terminates at the flat
aft portion to provide a generally continuous transition from the
chine to the flat base of the hull.
12. The boat hull according to claim 10, wherein a vertical
separation of the chines varies along a length of the chines to
allow the chines to transition from being generally aligned at the
bow through greater offset sections at mid bow to merge with a
generally flat underbody, and wherein a substantially vertical
surface is disposed between adjacent chines.
13. The boat hull according to claim 10, further comprising a
channel formed in opposite side walls of the hull at a rearward
location, the channels being configured to direct water inwardly
from opposite sides of the hull to merge behind the stern.
14. The boat hull according to claim 10, further comprising an
internal propulsion system for transferring displaced water from
under the hull to a low pressure void formed behind the hull.
15. The boat hull according to claim 14, wherein the internal
propulsion system includes an outlet which is adjustable in
aperture size to vary a water acceleration point in response to
speed changes.
16. The boat hull according to claim 14, wherein the flat aft
portion is formed in multiple vertically offset bottom segments and
chines which are centrally disposed terminate at a lowermost bottom
segment and incorporate an intake for the internal propulsion
system.
17. The boat hull according to claim 10, wherein the flat aft
portion is formed in multiple vertically offset bottom segments and
chines which are centrally disposed terminate in a lowermost bottom
segment, and wherein the lowermost bottom segment tapers towards
the stern.
18. The boat hull according to claim 14, further including a trim
tab extending from a lower rearward portion of the hull.
19. The boat hull according to claim 12, wherein a lower portion of
the hull is in the form of a displacement hull into which the
chines merge.
20. A boat, having at least one hull according to claim 8.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 15/579,163, entitled BOAT HULL and filed Dec.
1, 2017, which is the national phase of International Application
Serial No. PCT/AU2015/050308, entitled BOAT HULL and filed Jun. 4,
2015, the disclosure of which is hereby incorporated by reference
in its entirety for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to a boat hull. More
generally, the present invention relates to improvements to the
hydrodynamic efficiency of boat hulls, floats, sponsons or similar,
designed to operate in light and/or heavy weather conditions. In
addition, the invention relates to, among other things,
improvements in seaworthiness, structural integrity and
buildability of the aforementioned, referred to hereafter as a
`boat hull` or `hull`.
BACKGROUND OF THE INVENTION
[0003] Traditional boat hull design has evolved over many years
with each new design being a development of existing accepted
concepts. Traditionally, fast displacement and planing boat hull
designs are based on an immersed hull form travelling through the
water where the `V` hull form for high speed vessels is accepted as
being the optimum hull form for a variety of sea states. Designers
constantly face challenges related to the `V` hull form where each
design attribute presents inherent compromises between that
attribute and one or more others.
[0004] For example, a hull having a narrow entry will provide
reduced form resistance and subsequently be able to travel faster
through the water. The compromise being that the narrow bow
generates less lift, has less volume, and subsequently less
buoyancy, and therefore carries less payload and can have a
tendency to submarine through swells. To counter this, designers
incorporate a flared bow section. The introduction of the flared
bow does not increase payload but introduces additional internal
volume high up in the bow, and subsequently provides exponential
reserve buoyancy in the bow to provide a hull form that is intended
to ride over a swell. The flared bow also increases deck area and
helps prevent excessive amounts of water washing across the deck,
producing a `drier` boat. The compromise with this form is that
when the bow buries into a large swell, the hull presents a
relatively blunt form to the swell which increases wave-making
resistance and partially stalls the vessel's forward motion.
[0005] With regard to planing vessels, it is accepted that the
easiest way to get a vessel to plane is to provide a hull with a
flat underbody. The compromise with a flat underbody is that the
vessel is only suited to flat water operation due to poor
performance and excessive slamming loads in rough water. In
addition, a planing hull requires design attributes to promote lift
which is essential for the hull to transition from displacement
mode to planing mode and to continue to operate in planing
mode.
[0006] The reduction of slamming loads and generation of lift is
generally achieved with conventional hulls by the incorporation of
`V transverse sections below the waterline. With constant deadrise
hulls, the `V is constant along the length of the vessel which
often results in a compromise between accommodating slamming loads
at the bow and providing optimum planing performance. Variable
deadrise hulls generally transition from a deep, fine `V forward,
to a flatter `V aft. The fine `V forward section reduces slamming
loads but also reduces the lift required for the vessel to
transition from displacement mode to planing mode. The flatter `V
sections aft provide the planing surface. For operation,
essentially, the application of power `squeezes` the bow out of the
water, inclining the hull to allow it to be driven out of the water
and onto the plane. This squeezing motion propagates equal and
opposite forces on both sides of the hull as evidenced by the bow
wave, and is representative of the wave-making resistance of the
bow portion of the hull. These wave-making forces constitute large
energy losses.
[0007] The aft `V planing surfaces of a planing vessel provide the
planing area required for the hull to `ride` on the water when
operating in planing mode. These planing surfaces must maintain an
incline in the direction of travel to produce the lift required to
stay `on the plane`. The combination of the incline and the `V hull
form propagates an outflow of water from under the hull, as the
vessel travels forward, displacing large volumes of water from
under the hull. Consequently, the inclined bow buries the stern,
creating a void in the water immediately aft of the hull as a
result of water being displaced by the vessels motion. This void is
evidence of large energy losses.
[0008] The incline also increases the propulsion thrust line angle
from the horizontal, which reduces the efficiency of the vessel as
a whole. Inclined planing vessels also present a relatively broad
slamming area to the face of oncoming swells further reducing
efficiency, reducing comfort and introducing unnecessary slamming
loads and stresses to the vessel.
[0009] Planing hull designs, having broad planing aft sections,
vary greatly in design from displacement hulls, having diminishing
displacement aft, and operate most effectively at the speeds for
which they were designed. Displacement hulls by design cannot
operate as a planing vessel. However, a planing hull will operate
in displacement mode at low speed which is a compromise of the
design intent as it operates with a buried stern resulting in
increased eddy-making resistance and reduced efficiency.
[0010] In addition to the water being displaced by the hull form,
water is also displaced by the propulsion system through
propellers, water jets or similar. Displacing or relocating water
consumes energy, therefore the lower the volume of displaced water
and the shorter the displacement distance, the lower the energy
required.
[0011] In addition to the above, frictional resistance, which is
approximately proportionate to the wetted surface area, is inherent
in all hulls immersed in water while travelling through it. A
reduction in wetted surface area is one of the main focuses of hull
designers in an effort to reduce frictional resistance which is one
of the greatest contributors to energy losses in boat hulls. To
this end, attempts have been made to introduce air bubbles and air
films between the hull and the surface of the water with limited
practical success.
[0012] It is also highly desirable to have a shallow draft vessel
to access remote areas especially when running for cover in heavy
weather where shallow water may be the only safe refuge. The nature
of a `V hull is that they are immersed deeper into the water which
exposes the underside of the hull and running gear to potential
collisions with the bottom.
[0013] Preferred embodiments of the present invention seek to
overcome or ameliorate one or more of the above-mentioned
challenges, or at least provide a useful alternative.
SUMMARY OF THE INVENTION
[0014] According to one aspect of the invention there is provided a
boat hull, comprising a bow section which is generally V-shaped and
a flat aft section to allow an air film to be introduced under the
boat hull. Proximate to a location where the bow section meets the
flat aft section, there is provided at least one slot or round hole
which provides a low-pressure injection point for pumped or
drawn-in air and/or exhaust gas, for lubrication of an operative
surface of the flat aft section.
[0015] According to preferred embodiments, the at least one slot or
round hole is rear facing.
[0016] Preferably, the at least one slot or round hole is
configured to provide a sufficient pressure reduction to excite and
maintain a venturi effect.
[0017] The hull may further comprise a pump or blower for
distributing the air and/or exhaust gas to the at least one slot or
round hole.
[0018] Preferably, the air and/or exhaust gas is ducted from an
interior or exterior of the hull or from exhaust gasses from the
engine. Preferably, at least one slot or round hole is provided at
a leading edge of a channel formed between adjacent ribs.
[0019] The boat hull may further comprise secondary apertures
provided further aft of the said at least one slot or round
hole.
[0020] Preferably, the boat hull further comprises at least one
pair of generally vertical ribs extending longitudinally along the
underside of the hull towards the stern. Preferably, the boat hull
further comprises a pair of generally vertical ribs extending
downwardly from an outboard edge of the hull, the depth of the ribs
increasing towards the stern.
[0021] In some embodiments, the boat hull further comprises a
plurality of chines extending downwardly from a bow of the hull
towards a stern of the hull, each chine in transverse cross section
being substantially straight and substantially horizontal and
arranged so that a centreline of each chine lies in a plane which
is parallel to a plane extending through a centreline of an
adjacent chine. Between each chine is a generally vertical section,
a central chine sits lower and forward of adjacent chines which are
disposed progressively higher and rearward toward sides of the
hull, and an aft portion of a base of the hull is generally flat
and each chine terminates at the flat aft portion to provide a
generally continuous transition from the chine to the flat base of
the hull.
[0022] In other embodiments, the boat hull further comprises a
plurality of chines extending downwardly from a bow of the hull
towards a stern of the hull, each chine being, at least at a
forward portion thereof, in transverse cross section substantially
straight and inclined toward a central longitudinal plane of the
hull and arranged so that a centreline of each chine lies in a
plane which is parallel to a plane extending through a centreline
of an adjacent chine. A central chine sits lower and forward of
adjacent chines which are disposed progressively higher and
rearward toward sides of the hull, and an aft portion of a base of
the hull is generally flat and each chine terminates at the flat
aft portion to provide a generally continuous transition from the
chine to the flat base of the hull.
[0023] The boat hull may further comprise at least one pair of
generally vertical ribs extending along and downwardly from an
outboard edge of opposite chines, the ribs extending along the
underside of the hull towards the stern.
[0024] Preferably, a vertical separation of the chines varies along
a length of the chines to allow the chines to transition from being
generally aligned at the bow through greater offset sections at mid
bow to merge with a generally flat underbody and wherein a
substantially vertical surface is disposed between adjacent chines.
The chines may be trimmed at an intersection with a topside of the
bow. The chines may curve downwardly and towards the stern.
[0025] The boat hull may further comprise a channel formed in
opposite side walls of the hull at a rearward location, with the
channels being configured to direct water inwardly from opposite
sides of the hull to merge behind the stern. The boat hull may
further comprise an internal propulsion system for transferring
displaced water from under the hull to a low pressure void formed
behind the hull.
[0026] The internal propulsion system can include an outlet which
is adjustable in aperture size to vary a water acceleration point
in response to speed changes.
[0027] The flat aft portion may be formed in multiple vertically
offset bottom segments and chines which are centrally disposed
terminate at a lowermost bottom segment and incorporate an intake
for the internal propulsion system. Alternatively, the flat aft
portion is formed in multiple vertically offset bottom segments and
chines which are centrally disposed terminate in a lowermost bottom
segment, and wherein the lowermost bottom segment tapers towards
the stern.
[0028] The boat hull may further include a trim tab extending from
a lower rearward portion of the hull. Preferably, a lower portion
of the hull is in the form of a displacement hull into which the
chines merge.
[0029] According to another aspect of the invention, there is
provided a boat having a hull of the above described type.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Preferred embodiments of the invention will be further
described, by way of non-limiting example only, with reference to
the accompanying drawings in which:
[0031] FIG. 1 is a perspective view of a boat hull of one
embodiment of the invention;
[0032] FIG. 2 is a perspective view of a boat hull of another
embodiment;
[0033] FIG. 3 is rear perspective view of the boat hull of FIG.
2;
[0034] FIG. 4 is bottom view of the boat hull of FIG. 2;
[0035] FIG. 5 is a front view of the boat hull of FIG. 2;
[0036] FIG. 6 is a side view of a boat hull of another embodiment,
the boat hull being configured for offshore use or in heavy
weather;
[0037] FIG. 7 is a side view of a boat hull of another embodiment,
the boat hull being configured for use in protected waters or light
weather with the forward sections of the chines trimmed by the
curve of the bow topsides;
[0038] FIG. 8 is a side view of a boat hull of another embodiment,
the boat hull incorporating a lower displacement section;
[0039] FIG. 9 is a side view of the boat hull of FIG. 1;
[0040] FIG. 9A is a sectional view of the boat hull taken along
line A-A of FIG. 9;
[0041] FIG. 9B is a sectional view of the boat hull taken along
line B-B of FIG. 9;
[0042] FIG. 9C is a sectional view of the boat hull taken along
line C-C of FIG. 9;
[0043] FIG. 9D is an enlarged view of FIG. 9C;
[0044] FIG. 9E is a sectional view of the boat hull taken along
line E-E of FIG. 9;
[0045] FIG. 10 is a side view of the boat hull of another
embodiment, with lines indicating sectional views;
[0046] FIG. 10A is a sectional view of the boat hull taken along
line A-A of FIG. 10;
[0047] FIG. 10B is a sectional view of the boat hull taken along
line B-B of FIG. 10;
[0048] FIG. 10C is a sectional view of the boat hull taken along
line C-C of FIG. 10;
[0049] FIG. 10D is an enlarged view of FIG. 10C;
[0050] FIG. 10E is a sectional view of the boat hull taken along
line E-E of FIG. 10;
[0051] FIG. 11 is a side view of the boat hull of another
embodiment, with lines indicating sectional views;
[0052] FIG. 11A is a sectional view of the boat hull taken along
line A-A of FIG. 11;
[0053] FIG. 11B is a sectional view of the boat hull taken along
line B-B of FIG. 11;
[0054] FIG. 11C is a sectional view of the boat hull taken along
line C-C of FIG. 11;
[0055] FIG. 11D is a sectional view of the boat hull taken along
line D-D of FIG. 11;
[0056] FIG. 11E is an enlarged view of FIG. 11C;
[0057] FIG. 11F is an enlarged view of FIG. 11D;
[0058] FIG. 11G is a front perspective view of the boat hull of
FIG. 11 including vertical ribs along an outboard edge;
[0059] FIG. 11H is a rear perspective view of the boat hull of FIG.
11 including vertical ribs along an outboard edge;
[0060] FIG. 12 is a side view of a boat hull of another
embodiment;
[0061] FIGS. 12A and 12B are enlarged view of FIG. 12;
[0062] FIG. 13 is a perspective view of a boat hull of another
embodiment;
[0063] FIGS. 13A to 13C are enlarged perspective views of the boat
hull of FIG. 13;
[0064] FIG. 14 is a perspective view of a boat hull of another
embodiment showing an internal drive system outlet;
[0065] FIG. 15 is a perspective view of a boat hull of another
embodiment showing outlets for twin internal drive systems;
[0066] FIG. 16 is a perspective view of a boat hull of another
embodiment showing a vertically disposed section;
[0067] FIG. 17 is a perspective view of a boat hull of another
embodiment showing a tapered vertically disposed section;
[0068] FIG. 18 is an enlarged view of FIG. 16 showing an
outlet;
[0069] FIG. 19 is a perspective view of a boat hull of another
embodiment;
[0070] FIG. 20 is a side view of the hull of FIG. 19; and
[0071] FIG. 21 is a side view of a modified form of the hull of
FIG. 19.
DETAILED DESCRIPTION
[0072] With reference to FIG. 1, there is shown a boat hull 1
according to a preferred embodiment of the invention. The boat hull
1 comprises a plurality of chines 2 extending downwardly from a bow
10 of the hull 1 towards a stern 7 or a base 4 of the hull 1. Each
chine 2 is, in transverse cross section, substantially straight and
substantially horizontal, as can be seen in FIG. 9D. Each chine 2
is also arranged so that a centreline or a line along the centre of
the outer surface of the chine 2 lies in a plane which is parallel
to a central plane of an adjacent chine 2, i.e. the adjacent chine
is also configured so that a centreline of the chine lies in a
plane, as indicated by the exemplary dashed line planes in FIG. 1
and exemplary dashed centrelines in FIG. 9E. Accordingly, although
the chines 2 are inclined and offset from each other, in an
underneath view, as illustrated in FIG. 4, the chines 2 appear
parallel.
[0073] As can be seen in FIG. 9D, a substantially vertical surface
3 is disposed between adjacent chines 2. The vertical surface 3
allows the chines to be offset from each other without providing a
deflection surface that directs water outwardly to create a bow
wave. The vertical surfaces 3 vary in height along their lengths,
to allow the chines 2 to transition from a generally pointed bow 10
through the greatest offset sections at mid bow 5 (FIG. 2) where
slamming loads are minimised, to a generally flat underbody 4. The
forward end of the chines may be trimmed by the intersection of an
inward curvature of topsides 6, as shown in FIG. 7, thus
terminating the convergence of the chines at the bow.
[0074] As can be seen in FIG. 9E, 10E or 11E, a lower portion of
the hull 1 which is toward the bow 10 is generally V-shaped in
cross section. In this regard, the chines 2 provide a "stepped"
form that approximates a V shape so that the profile of the hull 1
is similar to that of a conventional V shaped hull, however, unlike
conventional V hulls the configuration of hull 1 is intended to
direct water downwardly and not outwardly. In this configuration, a
wave incident on the hull will first contact a central chine 5,
which is forward most in the portion which is toward the bow,
providing a small amount of lift and minimal resistance to the
hull. For progressively larger waves, adjacent chines will contact
the water later, collectively providing exponential lift, reserve
buoyancy and reduced resistance allowing the hull to ride over a
wave without significantly affecting forward motion of the
hull.
[0075] In a preferred form, at the design waterline, the hull 1 is
generally pointed at bow 10 and becomes progressively wider toward
the stern. This fine entry configuration reduces and accommodates
slamming loads on hull 1 as it passes through a swell, yet allows
the hull to provide sufficient lift for planing, suitable for
carrying loads and providing lateral stability.
[0076] Owing to the above configuration, as the hull 1 moves
through the water the chines 2 present a surface to the water which
acts to deflect the water substantially downwardly and underneath
the hull 1 to provide lift. By deflecting water downwardly, the
majority of the opposing forces from the water acting on the hull 1
provide lift to the hull 1.
[0077] The chines 2 can vary in size, number and profile according
to the desired application. In this regard, the width, depth and
profile of the chines can vary along with the number of chines. For
example, a hull configured for use in heavy swells, such as that
illustrated in FIG. 6, may have a larger number of narrower chines
which are larger or extend further upwardly, reducing the depth of
the topsides 6 towards gunwale 25. In contrast, a hull configured
for use in lighter swells may have a smaller number of wider chines
that, with a flatter profile, do not extend as high up the topsides
6 of the hull 1 as shown in FIG. 7. In a preferred form, the
central chine, which extends deepest into an approaching wave, is
narrowest with the width of the chines increasing as they move
outwardly.
[0078] As illustrated in FIGS. 10A to 10E, in another form the
chines may, at least at a forward portion thereof, be inclined
inwardly toward a central longitudinal plane of the hull. In such
an arrangement, outward flow of water from under the hull can be
limited. In this form, the chines may transition from inclined
inwardly at the bow to generally horizontal at the aft end of the
chine.
[0079] As illustrated in FIGS. 1 to 5, the hull 1 includes a number
of features present in conventional hulls. For example, topsides 6
extend from the outer edge of the outermost chines 2 on each side
of the hull 1 to the gunwale 25. A transom 8 interconnects the two
topsides 6 at the stern of the hull 7.
[0080] In a preferred form, the chines 2 curve downwardly toward
the flat hull underbody 4 of the hull 1. In other forms, the chines
2 may be planar and generally straight as they extend downwardly
from the bow 10 to the flat underbody 4 of the hull 1. The actual
contour or curvature of the chines will be selected having regard
to the intended application of the hull. In this regard, a hull
having chines with a small or flat contour will be more suitable
for use in lighter conditions, whereas a hull with steeply curved
chines will be more suitable for use in heavy swells. The forward
end of the chines may be trimmed by an intersection with the inward
curvature of the topsides 6 as shown in FIG. 7.
[0081] As illustrated in FIGS. 1 to 5, an aft portion or surface 4
of a base of the hull 1 is generally flat and each chine 2
terminates at the forward end 9 of the planing surface 4. As can be
seen in FIG. 4, the flat aft underbody surface 4 narrows toward a
forward end of the hull 1, with the central chine terminating at a
location which is forwardmost compared to the location at which the
outer chines terminate. As the flat surface 4 provides a relatively
large planing surface to the hull 1, it can have relatively flat
dynamic trim in use, increasing efficiency.
[0082] As illustrated in FIG. 3, the hull transitions into a
generally rectangular transom 8 or flat underbody 4. By
transitioning from a generally pointed bow 10 to a generally flat
underbody 4, the hull 1 not only achieves lift and provides optimum
flat aft planing surfaces to promote planing, but improves the
passage of the hull 1 over and through swells. According to
preferred embodiments, when compared to previous hulls, the hull 1
can also provide a more efficient hull capable of carrying a
payload, with a large, dry deck area, that effectively rides over
large swells while accommodating slamming loads.
[0083] In the embodiment illustrated in FIG. 8, the hull 1 can be
modified for use as a displacement hull, thereby allowing large
loads to be carried. Such a hull can potentially be used for
commercial shipping applications, while providing a dampening
effect on the oscillation of the hull as it is subjected to ocean
swells.
[0084] According to the embodiment illustrated in FIG. 11D,
generally vertical and downwardly extending ribs 15 may be provided
along the outside edges of the central or at least one pair of
opposite planing chines 2 to contain and channel air against the
underside of the chines 2 and flat underbody 4 to lubricate the
hull. Air may be provided via a slot or hole, or simply trapped as
the vessel travels over the irregular water surface. The or each
rib 15 is preferably narrow with, as far as practicable, right
angled internal corners 12 to minimise turbulence. The size, i.e.
width and depth, of each rib 15 is selected relative to the
intended area of operation and purpose of the vessel to which the
hull is to be applied. The depth of the rib may vary along its
length. Ribs may run the full length of the chine or start at the
slot to contain air and/or gas introduced at the slot. In a
preferred form, the or each rib continues along the underside of
the hull towards the stern 7.
[0085] As can be seen in FIGS. 11G and 11H, the outermost ribs 15
form longitudinal fins extending along an outer side of the hull.
The outermost ribs are also generally vertical and extend
downwardly from the hull and increase in size or get deeper toward
the stern 7. Ribs 15 act to keep water and air retained under the
hull to lubricate the bottom surface of the hull and reduce
drag.
[0086] The illustrated embodiments each chine transitions into a
generally flat underbody which can create skin friction drag as the
hull moves through the water. To reduce frictional drag, each chine
can have, near a trailing end, a device 23 for introducing air
and/or gas to create an air/gas film layer, bubbles or to reduce
the density of the medium in contact with the hull. In one
embodiment, air or gas can flow through the aperture onto an
operative surface of the chine 2 and flat hull underbody 4. In a
preferred form, the aperture is substantially in the form of a slot
or round hole. The slot can have a horizontal and rear facing
opening providing a low pressure injection point for the air and/or
gas. Preferably the pressure reduction is sufficient to excite and
maintain a venturi effect. Gas injection may be assisted via a
pump, blower or similar. An example of such a configuration is
shown in FIGS. 12, 12A and 12B. The device is provided in at least
one of the chines and can be provided in multiple or all of the
chines. Secondary apertures may be provided further aft as shown in
FIG. 12B to reinstate dissipated gases. The air and/or gas can flow
from numerous locations ducted from above the floatation waterline,
such as from an interior or exterior of the hull or from exhaust
gasses from the engine. Air and/or exhaust gas may be introduced
via a venturi slot or low pressure injection point via at least one
aperture formed.
[0087] The illustrated embodiments of a planing type hull
transition into a generally flat underbody 4, which can create drag
inducing eddies as the hull moves through the water at slow or
displacement speeds or a void in the water at high speeds. FIGS. 13
to 13C and 14 to 17 illustrate another embodiment of hull 1, having
voids 17 in the form of cutaway sections or channels at the stern
to direct water behind the hull as it moves through the water to
reduce drag. The voids are inset into each side of the hull near
the stern, with an upper edge starting near the design floatation
waterline and extending down to marginally above flat bottom
portion 19. The voids 17 extend from a location forward of the
transom on the sides of the hull to and through the stern near the
centreline 22. The voids 17 allow the water to fully or partially
merge at the stern 22 whilst maintaining a flat planing bottom
surface.
[0088] In the embodiments illustrated in FIGS. 14 to 18, an aft end
or merge point 22 (refer FIGS. 13A to 13C) can accommodate an
outlet 24 of an internal propulsion system for transferring
displaced water from under the hull to occupy the void in the water
behind the hull. FIG. 18 is an enlargement of the outlet 24 shown
in FIG. 16, as indicated by the dashed line box in FIG. 16. The
outlet 24 may be adjustable in size to move the water acceleration
point further aft as speed increases, as indicated by the dashed
line in FIG. 18. As shown in FIG. 15, the merge point may
accommodate more than one drive outlet 24.
[0089] The illustrated embodiments shown in FIGS. 14 and 15 show a
longitudinal water intake 26, through which displaced water is
drawn from under the hull and through an internal drive system.
[0090] FIGS. 16 and 17 illustrate embodiments having a plurality of
flat bottom segments 4A, 4B into which the chines 2 transition. In
this regard, central chines transition into a lowermost flat bottom
segment 4A and outer chines transition into flat bottom segments 4B
which are disposed beside segment 4A. The lowermost flat bottom
segment 4A forms part of a vertically disposed section and it will
be appreciated that single or multiple chines may transition into
each flat bottom segment and that additional flat bottom segments
may also be provided.
[0091] The hull illustrated in FIG. 16 has a lowermost flat bottom
segment 4A with a generally constant width, while the hull
illustrated in FIG. 17 has vertically disposed central chines which
displace water downwards at the bow providing additional lift and
forward buoyancy. The flat bottom segment 4A then tapers aft of the
chine in plan view to horizontally draw water displaced by the aft
sections of the hull, under the hull.
[0092] The embodiments shown in FIGS. 16 and 17 include an internal
propulsion system (not shown) that draws displaced water from each
side of the vertically disposed section through longitudinal water
intakes 26 as the water is displaced. The vertically disposed
section accommodates the longitudinal water intakes 26 to position
the intakes away from the air trapped immediately under the hull.
The displaced water is drawn through the internal propulsion system
and deposited into the void behind the hull through outlets 24. The
vertically displaced section aft of the chines may have parallel
sides in plan view as shown in FIG. 16 or be tapered in plan view
as shown in FIG. 17.
[0093] The vertically displaced section of FIG. 16 is lower than
the level at which outer chines terminate and provided so that the
water intake for the internal propulsion system is lower in the
flow path of water moving under the hull to reduce air being drawn
into the internal propulsion system.
[0094] Although it is preferred that the tapered vertically
displaced section of FIG. 17 be used with an internal propulsion
system, it should be noted that this feature may be incorporated
into a hull without an internal propulsion system.
[0095] The internal propulsion system may include propellers and/or
impellers configured in an internal duct and driven by one or more
engines located within the hull. The duct includes one or more
longitudinal water intakes 26 located under the hull through which
water is drawn by the ducted propellers/impellers. The duct is also
connected to an output 24 located at the stern merge point 22 of
the hull where the output water is deposited into the negative
pressure region behind the hull.
[0096] The propellers and/or impellers may be configured as a
single propeller/impeller or in counter-rotating in-line ducted
sets. At lower speeds the thrust is developed at the
propeller/impeller where the differential pressure across the
propeller/impeller provides the thrust. At high speed, the outlet
aperture 24 of the internal drive system may be reduced in cross
sectional area to move the water acceleration point from the
propellers to the internal drive system outlet 24 wherein the
propulsion system acts more like a water jet.
[0097] In the embodiment illustrated in FIG. 13C, a trim tab 27 can
extend from a lower rearward portion of the hull and is
incorporated into the aft planing surface 4. The trim tab 27
extends transverse to the water flow and rearwardly from surface 4.
The trim tab is arranged to allow water to pass over the top and
underside thereof to increase lift provided. Although a single trim
tab 27 is shown, it may be formed of numerous individual elements.
Trim tabs may be adjustable. Trim tabs may be independently
adjustable to provide transverse stabilization.
[0098] The hull 1 is symmetrical about a central longitudinal plane
of the hull when used for a monohull vessel, as illustrated in
FIGS. 1 to 12. A pair of demi hulls 1 may also be provided for a
twin hull vessel such as a catamaran, as illustrated in FIG. 13,
with each hull being configured as described above. In such an
embodiment, each demi hull may not be symmetrical about its central
longitudinal plane, but symmetrical about a central longitudinal
plane of the vessel.
[0099] FIGS. 19 to 21 illustrate another embodiment of the
invention, having a more traditional V-Shaped hull 101 and a flat
bottom, though it will be appreciated that hull 101 may take forms
other than strictly V-shaped. In the illustrated embodiment, like
reference numerals incremented by 100 are used to indicate like
features described in relation to hull 1, and it is intended that
the preceding description applies to like features where
applicable.
[0100] Hull 101 has a device 123 for introducing air and/or gas to
create an air/gas film layer is provided. Preferably, device 123 is
in the form of apertures, slots or round holes near where the bow
section meets the flat aft section.
[0101] Introducing air and/or gas under the hull 101 creates an
air/gas film layer, bubbles or a reduction in the density of the
medium in contact with the hull. In one embodiment, air or gas can
flow through the aperture onto the flat hull underbody 104. In a
preferred form, the aperture is substantially in the form of a slot
or round hole. The slot can have a horizontal and rear facing
opening providing a low-pressure injection point for the air and/or
gas. Preferably the pressure reduction is sufficient to excite and
maintain a venturi effect. Gas injection may be assisted via a
pump, blower or similar. An example of such a configuration is
shown in FIGS. 12, 12A, and 12B. The device can be provided at
multiple locations. Secondary apertures may be provided further aft
as shown in FIG. 12B to reinstate dissipated gases. The air and/or
gas can flow from numerous locations ducted from above the
floatation waterline, such as from an interior or exterior of the
hull or from exhaust gasses from the engine. Air and/or exhaust gas
may be introduced via a venturi slot or low-pressure injection
point via at least one aperture formed.
[0102] The flat bottom of hull 101 not only provides stability but
also accommodates the air film underneath the hull 101, thereby
reducing drag.
[0103] According to the embodiment illustrated in FIG. 11D,
generally vertical and downwardly extending ribs 115 may be
provided along the flat bottom 104, extending longitudinally along
the flat bottom, i.e. parallel to a longitudinal plane, to contain
and channel air against the underside of the flat underbody 104 to
lubricate the hull. As described above, air may be provided via a
slot or hole, or simply trapped as the vessel travels over the
irregular water surface. Each rib 115 is preferably narrow with, as
far as practicable, right angled internal corners to minimise
turbulence. The size, i.e. width and depth, of each rib 115 is
selected relative to the intended area of operation and purpose of
the vessel to which the hull is to be applied. The depth of each
rib 115 may vary along its length. Ribs 115 may run the full length
of the flat bottom 104 or start at the slot to contain air and/or
gas introduced at the slot. In a preferred form, each rib 115
continues along the underside of the hull towards the stern
107.
[0104] As can be seen in FIGS. 11G and 11H, the outermost ribs 115
form longitudinal fins extending along an outer side of the hull.
The outermost ribs 115 are also generally vertical and extend
downwardly from the hull and increase in size or get deeper toward
the stern 107. Ribs 115 act to keep water and air bubbles retained
under the hull to lubricate the bottom surface of the hull and
reduce drag.
[0105] Hull 101 may take the form of a conventional V-shape as
shown, or that of a displacement hull as shown in the broken lines
in FIGS. 20 and 21, thereby allowing large loads to be carried.
Such a hull can potentially be used for commercial shipping
applications. In accordance with conventional displacement hulls,
an upturned rear portion 45 is provided.
[0106] The hull 101 may incorporate the features described above,
such as: [0107] voids in the form of cutaway sections or channels
at the stern to direct water behind the hull as it moves through
the water to reduce drag; [0108] an outlet of an internal
propulsion system for transferring displaced water from under the
hull to occupy the void in the water behind the hull; [0109] a
longitudinal water intake; and/or [0110] a trim tab extending from
a lower rearward portion of the hull.
[0111] These features may be incorporated into hull 101 either
individually or in combination.
[0112] The embodiments have been described by way of example only
and modifications are possible within the scope of the invention
disclosed. For example, the number, profile and size of the chines
and their separation may be varied, as can the size of the flat
portion of the base. Furthermore, the vessel may be manufactured
from flat materials including metals, timbers, fibre reinforced
plastics and composites.
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