U.S. patent application number 14/524992 was filed with the patent office on 2016-02-04 for buoyant structure.
The applicant listed for this patent is SSP TECHNOLOGIES, INC.. Invention is credited to Nicolaas Johannes Vandenworm.
Application Number | 20160031534 14/524992 |
Document ID | / |
Family ID | 55179230 |
Filed Date | 2016-02-04 |
United States Patent
Application |
20160031534 |
Kind Code |
A1 |
Vandenworm; Nicolaas
Johannes |
February 4, 2016 |
BUOYANT STRUCTURE
Abstract
A buoyant structure having a hull, a main deck, an upper
cylindrical side section extending downwardly from the main deck,
an upper frustoconical side section, a cylindrical neck, a lower
ellipsoidal section that extends from the cylindrical neck, an
ellipsoidal keel and a fin-shaped appendage secured to a lower and
an outer portion of the exterior of the ellipsoid keel. The upper
frustoconical side section located below the upper cylindrical side
section and maintained to be above a water line for a transport
depth and partially below the water line for an operational depth
of the buoyant structure.
Inventors: |
Vandenworm; Nicolaas Johannes;
(Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SSP TECHNOLOGIES, INC. |
Grand Cayman |
KY |
US |
|
|
Family ID: |
55179230 |
Appl. No.: |
14/524992 |
Filed: |
October 27, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14105321 |
Dec 13, 2013 |
8869727 |
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14524992 |
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13369600 |
Feb 9, 2012 |
8662000 |
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14105321 |
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12914709 |
Oct 28, 2010 |
8251003 |
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13369600 |
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61259201 |
Nov 8, 2009 |
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61262533 |
Nov 18, 2009 |
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Current U.S.
Class: |
114/264 |
Current CPC
Class: |
B63B 35/44 20130101;
B63B 1/041 20130101; B63B 2021/003 20130101; B63B 21/50 20130101;
B63B 39/02 20130101; E02B 3/20 20130101; B63B 2021/001
20130101 |
International
Class: |
B63B 35/44 20060101
B63B035/44; B63B 21/50 20060101 B63B021/50 |
Claims
1. A buoyant structure comprising: a hull having a main deck, an
upper cylindrical side section, an upper frustoconical side
section, a cylindrical neck, a lower frustoconical side section
that extends from the cylindrical neck, a lower ellipsoidal
section, an ellipsoid keel, and a fin-shaped appendage secured to a
lower and an outer portion of the exterior of the ellipsoid
keel.
2. The buoyant structure of claim 1, wherein a pendulum is
positioned to move between a transport depth and an operational
depth, and wherein the pendulum is configured to dampen movement of
a watercraft as the watercraft moves from side to side in
water.
3. The buoyant structure of claim 1, wherein the main deck has a
superstructure comprising at least one member selected from the
group consisting of: crew accommodations, a heliport, a crane, a
control tower, a dynamic position system in the control tower, and
an aircraft hangar.
4. The buoyant structure of claim 1, wherein the hull has a
berthing facility and catenary mooring lines for mooring the
buoyant structure to a seafloor.
5. The buoyant structure of claim 1, further comprising a gangway
for traversing between the buoyant structure and a watercraft.
6. The buoyant structure of claim 1, comprising the hull with a
center of gravity below a center of buoyancy to provide an inherent
stability to the buoyant structure.
7. The buoyant structure of claim 1, wherein the upper
frustoconical side section engages the cylindrical neck, wherein
the buoyant structure comprises: a. the upper cylindrical side
section extending downwardly from the main deck; and b. the upper
frustoconical side section located below the upper cylindrical side
section and maintained to be above a water line for a transport
depth and partially below a water line for an operational depth of
the buoyant structure; and wherein the upper frustoconical side
section has a gradually reducing diameter from a diameter of the
upper cylindrical side section.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Continuation in Part of
co-pending U.S. patent application Ser. No. 14/105,321 filed on
Dec. 13, 2013, entitled "BUOYANT STRUCTURE," which is a
Continuation in Part of co-pending U.S. patent application Ser. No.
13/369,600 filed on Feb. 9, 2012, entitled "STABLE OFFSHORE
FLOATING DEPOT," now issued as U.S. Pat. No. 8,662,000 on Mar. 4,
2014, which is a Continuation in Part of U.S. patent application
Ser. No. 12/914,709 filed on Oct. 28, 2010, now issued as U.S. Pat.
No. 8,251,003 on Aug. 28, 2012, which claims the benefit of U.S.
Provisional Patent Application Ser. No. 61/521,701 filed on Aug. 9,
2011, U.S. Provisional Patent Application Ser. No. 61/259,201 filed
on Nov. 8, 2009 and U.S. Provisional Patent Application Ser. No.
61/262,533 filed on Nov. 18, 2009. These references are hereby
incorporated in their entirety.
FIELD
[0002] The present embodiments generally relate to a buoyant
structure for supporting offshore oil and gas operations.
BACKGROUND
[0003] A need exists for a buoyant structure that provides kinetic
energy absorption capabilities from a watercraft by providing a
plurality of dynamic movable tendering mechanisms in a tunnel
formed in the buoyant structure.
[0004] A further need exists for a buoyant structure that provides
wave damping and wave breakup within a tunnel formed in the buoyant
structure.
[0005] A need exists for a buoyant structure that provides friction
forces to a hull of a watercraft in the tunnel.
[0006] The present embodiments meet these needs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The detailed description will be better understood in
conjunction with the accompanying drawings as follows:
[0008] FIG. 1 is a perspective view of a buoyant structure.
[0009] FIG. 2 is a vertical profile drawing of the hull of the
buoyant structure.
[0010] FIG. 3 is an enlarged perspective view of the floating
buoyant structure at operational depth.
[0011] FIG. 4A is a top view of a plurality of dynamic moveable
tendering mechanisms in a tunnel before a watercraft has contacted
the dynamic moveable tendering mechanisms.
[0012] FIG. 4B is a top view of a plurality of dynamic moveable
tendering mechanisms in a tunnel as the hull of a watercraft has
contacted the dynamic moveable tendering mechanisms.
[0013] FIG. 4C is a top view of a plurality of dynamic moveable
tendering mechanisms in a tunnel connecting to the watercraft with
the doors closed.
[0014] FIG. 5 is an elevated perspective view of one of the dynamic
moveable tendering mechanisms.
[0015] FIG. 6 is a collapsed top view of one of the dynamic
moveable tendering mechanisms.
[0016] FIG. 7 is a side view of an embodiment of the dynamic
moveable tendering mechanism.
[0017] FIG. 8 is a side view of another embodiment of the dynamic
moveable tendering mechanism.
[0018] FIG. 9 is a cut away view of the tunnel.
[0019] FIG. 10 is a top view of a Y-shaped tunnel in the hull of
the buoyant structure.
[0020] FIG. 11 is a side view of the buoyant structure with a
cylindrical neck.
[0021] FIG. 12 is detailed view of the buoyant structure with a
cylindrical neck.
[0022] FIG. 13 is a cut away view of the buoyant structure with a
cylindrical neck in a transport configuration.
[0023] FIG. 14 is a cut away view of the buoyant structure with a
cylindrical neck in an operational configuration.
[0024] The present embodiments are detailed below with reference to
the listed Figures.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] Before explaining the present apparatus in detail, it is to
be understood that the apparatus is not limited to the particular
embodiments and that it can be practiced or carried out in various
ways.
[0026] The present embodiments relate to a buoyant structure for
supporting offshore oil and gas operations.
[0027] The embodiments enable safe entry of a watercraft into a
buoyant structure in both harsh and benign offshore water
environments, with 4 foot to 40 foot seas.
[0028] The embodiments prevent injuries to personnel from equipment
falling off the buoyant structure by providing a tunnel to contain
and protect watercraft for receiving personnel within the buoyant
structure.
[0029] The embodiments provide a buoyant structure located in an
offshore field that enables a quick exit from the offshore
structure by many personnel simultaneously, in the case of an
approaching hurricane or tsunami.
[0030] The embodiments provide a means to quickly transfer many
personnel, such as from 200 to 500 people safely from an adjacent
platform on fire to the buoyant structure in less than 1 hour.
[0031] The embodiments enable the offshore structure to be towed to
an offshore disaster and operate as a command center to facilitate
in the control of a disaster, and can act as a hospital, or triage
center.
[0032] Turning now to the Figures, FIG. 1 depicts a buoyant
structure for operationally supporting offshore exploration,
drilling, production, and storage installations according to an
embodiment of the invention.
[0033] The buoyant structure 10 can include a hull 12, which can
carry a superstructure 13 thereon. The superstructure 13 can
include a diverse collection of equipment and structures, such as
living quarters and crew accommodations 58, equipment storage, a
heliport 54, and a myriad of other structures, systems, and
equipment, depending on the type of offshore operations to be
supported. Cranes 53 can be mounted to the superstructure. The hull
12 can be moored to the seafloor by a number of catenary mooring
lines 16. The superstructure can include an aircraft hangar 50. A
control tower 51 can be built on the superstructure. The control
tower can have a dynamic position system 57.
[0034] The buoyant structure 10 can have a tunnel 30 with a tunnel
opening in the hull 12 to locations exterior of the tunnel.
[0035] The tunnel 30 can receive water while the buoyant structure
10 is at an operational depth 71.
[0036] The buoyant structure can have a unique hull shape.
[0037] Referring to FIGS. 1 and 2, the hull 12 of the buoyant
structure 10 can have a main deck 12a, which can be circular; and a
height H. Extending downwardly from the main deck 12a can be an
upper frustoconical portion 14.
[0038] In embodiments, the upper frustoconical portion 14 can have
an upper cylindrical side section 12b extending downwardly from the
main deck 12a, an inwardly-tapering upper frustoconical side
section 12g located below the upper cylindrical side section 12b
and connecting to a lower inwardly-tapering frustoconical side
section 12c.
[0039] The buoyant structure 10 also can have a lower frustoconical
side section 12d extending downwardly from the lower
inwardly-tapering frustoconical side section 12c and flares
outwardly. Both the lower inwardly-tapering frustoconical side
section 12c and the lower frustoconical side section 12d can be
below the operational depth 71.
[0040] A lower ellipsoidal section 12e can extend downwardly from
the lower frustoconical side section 12d, and a matching
ellipsoidal keel 12f.
[0041] The lower inwardly-tapering frustoconical side section 12c
can have a substantially greater vertical height H1 than lower
frustoconical side section 12d shown as H2.
[0042] Upper cylindrical side section 12b can have a slightly
greater vertical height H3 than lower ellipsoidal section 12e shown
as H4.
[0043] As shown, the upper cylindrical side section 12b can connect
to inwardly-tapering upper frustoconical side section 12g so as to
provide for a main deck of greater radius than the hull radius
along with the superstructure 13, which can be round, square or
another shape, such as a half moon. Inwardly-tapering upper
frustoconical side section 12g can be located above the operational
depth 71.
[0044] The tunnel 30 can have at least one closable door 34a and
34b that alternatively or in combination, can provide for weather
and water protection to the tunnel 30.
[0045] Fin-shaped appendages 84 can be attached to a lower and an
outer portion of the exterior of the hull.
[0046] The hull 12 is depicted with a plurality of catenary mooring
lines 16 for mooring the buoyant structure to create a mooring
spread.
[0047] FIG. 2 is a simplified view of a vertical profile of the
hull according to an embodiment.
[0048] The tunnel 30 can have a plurality of dynamic movable
tendering mechanisms 24d and 24h disposed within and connected to
the tunnel sides.
[0049] In an embodiment, the tunnel 30 can have closable doors 34a
and 34b for opening and closing the tunnel opening 31.
[0050] The tunnel floor 35 can accept water when the buoyant
structure is at an operational depth 71.
[0051] Two different depths are shown, the operational depth 71 and
the transit depth 70.
[0052] The dynamic movable tendering mechanisms 24d and 24h can be
oriented above the tunnel floor 35 and can have portions that are
positioned both above the operational depth 71 and extend below the
operational depth 71 inside the tunnel 30.
[0053] The main deck 12a, upper cylindrical side section 12b,
inwardly-tapering upper frustoconical side section 12g, lower
inwardly-tapering frustoconical side section 12c, lower
frustoconical side section 12d, lower ellipsoidal section 12e, and
matching ellipsoidal keel 12f are all co-axial with a common
vertical axis 100. In embodiments, the hull 12 can be characterized
by an ellipsoidal cross section when taken perpendicular to the
vertical axis 100 at any elevation.
[0054] Due to its ellipsoidal planform, the dynamic response of the
hull 12 is independent of wave direction (when neglecting any
asymmetries in the mooring system, risers, and underwater
appendages), thereby minimizing wave-induced yaw forces.
Additionally, the conical form of the hull 12 is structurally
efficient, offering a high payload and storage volume per ton of
steel when compared to traditional ship-shaped offshore structures.
The hull 12 can have ellipsoidal walls which are ellipsoidal in
radial cross-section, but such shape may be approximated using a
large number of flat metal plates rather than bending plates into a
desired curvature. Although an ellipsoidal hull planform is
preferred, a polygonal hull planform can be used according to
alternative embodiments.
[0055] In embodiments, the hull 12 can be circular, oval or
elliptical forming the ellipsoidal planform.
[0056] An elliptical shape can be advantageous when the buoyant
structure is moored closely adjacent to another offshore platform
so as to allow gangway passage between the two structures. An
elliptical hull can minimize or eliminate wave interference.
[0057] The specific design of the lower inwardly-tapering
frustoconical side section 12c and the lower frustoconical side
section 12d generates a significant amount of radiation damping
resulting in almost no heave amplification for any wave period, as
described below.
[0058] Lower inwardly-tapering frustoconical side section 12c can
be located in the wave zone. At operational depth 71, the waterline
can be located on lower inwardly-tapering frustoconical side
section 12c just below the intersection with upper cylindrical side
section 12b. Lower inwardly-tapering frustoconical side section 12c
can slope at an angle (.alpha.) with respect to the vertical axis
100 from 10 degrees to 15 degrees. The inward flare before reaching
the waterline significantly dampens downward heave, because a
downward motion of the hull 12 increases the waterplane area. In
other words, the hull area normal to the vertical axis 100 that
breaks the water's surface will increase with downward hull motion,
and such increased area is subject to the opposing resistance of
the air and or water interface. It has been found that 10 degrees
to 15 degrees of flare provides a desirable amount of damping of
downward heave without sacrificing too much storage volume for the
vessel.
[0059] Similarly, lower frustoconical side section 12d dampens
upward heave. The lower frustoconical side section 12d can be
located below the wave zone (about 30 meters below the waterline).
Because the entire lower frustoconical side section 12d can be
below the water surface, a greater area (normal to the vertical
axis 100) is desired to achieve upward damping. Accordingly, the
first diameter D.sub.1 of the lower hull section can be greater
than the second diameter D.sub.2 of the lower inwardly-tapering
frustoconical side section 12c. The lower frustoconical side
section 12d can slope at an angle (.gamma.) with respect to the
vertical axis 100 from 55 degrees to 65 degrees. The lower section
can flare outwardly at an angle greater than or equal to 55 degrees
to provide greater inertia for heave roll and pitch motions. The
increased mass contributes to natural periods for heave pitch and
roll above the expected wave energy. The upper bound of 65 degrees
is based on avoiding abrupt changes in stability during initial
ballasting on installation. That is, lower frustoconical side
section 12d can be perpendicular to the vertical axis 100 and
achieve a desired amount of upward heave damping, but such a hull
profile would result in an undesirable step-change in stability
during initial ballasting on installation. The connection point
between upper frustoconical portion 14 and the lower frustoconical
side section 12d can have a third diameter D.sub.3 smaller than the
first and second diameters D.sub.1 and D.sub.2.
[0060] The transit depth 70 represents the waterline of the hull 12
while it is being transited to an operational offshore position.
The transit depth is known in the art to reduce the amount of
energy required to transit a buoyant vessel across distances on the
water by decreasing the profile of buoyant structure which contacts
the water. The transit depth is roughly the intersection of lower
frustoconical side section 12d and lower ellipsoidal section 12e.
However, weather and wind conditions can provide need for a
different transit depth to meet safety guidelines or to achieve a
rapid deployment from one position on the water to another.
[0061] In embodiments, the center of gravity of the offshore vessel
can be located below its center of buoyancy to provide inherent
stability. The addition of ballast to the hull 12 is used to lower
the center of gravity. Optionally, enough ballast can be added to
lower the center of gravity below the center of buoyancy for
whatever configuration of superstructure and payload is to be
carried by the hull 12.
[0062] The hull is characterized by a relatively high metacenter.
But, because the center of gravity (CG) is low, the metacentric
height is further enhanced, resulting in large righting moments.
Additionally, the peripheral location of the fixed ballast further
increases the righting moments.
[0063] The buoyant structure aggressively resists roll and pitch
and is said to be "stiff." Stiff vessels are typically
characterized by abrupt jerky accelerations as the large righting
moments counter pitch and roll. However, the inertia associated
with the high total mass of the buoyant structure, enhanced
specifically by the fixed ballast, mitigates such accelerations. In
particular, the mass of the fixed ballast increases the natural
period of the buoyant structure to above the period of the most
common waves, thereby limiting wave-induced acceleration in all
degrees of freedom.
[0064] In an embodiment, the buoyant structure can have thrusters
99a-99d.
[0065] FIG. 3 shows the buoyant structure 10 with the main deck 12a
and the superstructure 13 over the main deck.
[0066] In embodiments, the crane 53 can be mounted to the
superstructure 13, which can include a heliport 54.
[0067] In this view a watercraft 200 is in the tunnel having come
into the tunnel through the tunnel opening 30 and is positioned
between the tunnel sides, of which tunnel side 202 is labeled. A
boat lift 41 is also shown in the tunnel, which can raise the
watercraft above the operational depth in the tunnel.
[0068] The tunnel opening 30 is shown with two doors, each door
having a door fender 36a and 36b for mitigating damage to a
watercraft attempting to enter the tunnel, but not hitting the
doors.
[0069] The door fenders can allow the watercraft to impact the door
fenders safely if the pilot cannot enter the tunnel directly due to
at least one of large wave and high current movement from a
location exterior of the hull.
[0070] The catenary mooring lines 16 are shown coming from the
upper cylindrical side section 12b.
[0071] A berthing facility 60 is shown in the hull 12 in the
portion of the inwardly-tapering upper frustoconical side section
12g. The inwardly-tapering upper frustoconical side section 12g is
shown connected to the lower inwardly-tapering frustoconical side
section 12c and the upper cylindrical side section 12b.
[0072] FIG. 4A shows the watercraft 200 entering the tunnel between
tunnel sides 202 and 204 and connecting to the plurality of dynamic
movable tendering mechanisms 24a-24h. Proximate to the tunnel
opening are closable doors 34a and 34b which can be sliding pocket
doors to provide either a weather tight or water tight protection
of the tunnel from the exterior environment. The starboard side 206
hull and port side 208 hull of the watercraft are also shown.
[0073] FIG. 4B shows the watercraft 200 inside a portion of the
tunnel between tunnel sides 202 and 204 and connecting to the
plurality of dynamic movable tendering mechanisms 24a-24h. Dynamic
moveable tendering mechanisms 24g and 24h are shown contacting the
port side 208 hull of the watercraft 200. Dynamic moveable
tendering mechanisms 24c and 24d are seen contacting the starboard
side 206 hull of the watercraft 200. The closable doors 34a and 34b
are also shown.
[0074] FIG. 4C shows the watercraft 200 in the tunnel between
tunnel sides 202 and 204 and connecting to the plurality of dynamic
movable tendering mechanisms 24a-24h and also connected to a
gangway 77. Proximate to the tunnel opening are closable doors 34a
and 34b which can be sliding pocket doors oriented in a closed
position providing either a weather tight or water tight protection
of the tunnel from the exterior environment. The plurality of the
dynamic moveable tendering mechanisms 24a-24h are shown in contact
with the hull of the watercraft on both the starboard side 206 and
port side 208.
[0075] FIG. 5 shows one of the plurality of the dynamic movable
tendering mechanisms 24a. Each dynamic movable tendering mechanism
can have a pair of parallel arms 39a and 39b mounted to a tunnel
side, shown as tunnel side 202 in this Figure.
[0076] A fender 38a can connect to the pair of parallel arm 39a and
39b on the sides of the parallel arms opposite the tunnel side.
[0077] A plate 43 can be mounted to the pair of parallel arms 39a
and 39b and between the fender 38a and the tunnel side 202.
[0078] The plate 43 can be mounted above the tunnel floor 35 and
positioned to extend above the operational depth 71 in the tunnel
and below the operational depth 71 in the tunnel
simultaneously.
[0079] The plate 43 can be configured to dampen movement of the
watercraft as the watercraft moves from side to side in the tunnel.
The plate and entire dynamic movable tendering mechanism can
prevent damage to the ship hull, and push a watercraft away from a
ship hull without breaking towards the tunnel center. The
embodiments can allow a vessel to bounce in the tunnel without
damage.
[0080] A plurality of pivot anchors 44a and 44b can connect one of
the parallel arms to the tunnel side.
[0081] Each pivot anchor can enable the plate to swing from a
collapsed orientation against the tunnel sides to an extended
orientation at an angle 60, which can be up to 90 degrees from a
plane 61 of the wall enabling the plate on the parallel arm and the
fender to simultaneously (i) shield the tunnel from waves and water
sloshing effects, (ii) absorb kinetic energy of the watercraft as
the watercraft moves in the tunnel, and (iii) apply a force to push
against the watercraft keeping the watercraft away from the side of
the tunnel.
[0082] A plurality of fender pivots 47a and 47b are shown, wherein
each pivot can form a connection between each parallel arm and the
fender 38a, each fender pivot can allow the fender to pivot from
one side of the parallel arm to an opposite side of the parallel
arm through at least 90 degrees as the watercraft contacts the
fender 38a.
[0083] A plurality of openings 52a-52ae in the plate 43 can reduce
wave action. Each opening can have a diameter from 0.1 meters to 2
meters. In embodiments, the openings 52 can be elipses.
[0084] At least one hydraulic cylinder 28a and 28b can be connected
to each parallel arm for providing resistance to watercraft
pressure on the fender and for extending and retracting the plate
from the tunnel sides.
[0085] FIG. 6 shows one of the pair of parallel arms 39a mounted to
a tunnel side 202 in a collapsed position.
[0086] The parallel arm 39a can be connected to the pivot anchor
44a that engages the tunnel side 202.
[0087] Fender pivot 47a can be mounted on the parallel arm opposite
the anchor pivot.
[0088] The fender 38a can be mounted to the fender pivot 47a.
[0089] The plate 43 can be attached to the parallel arm 39a.
[0090] The hydraulic cylinder 28a can be attached to the parallel
arm and the tunnel wall.
[0091] FIG. 7 shows the plate 43 with openings 52a-52ag that can be
ellipsoidal in shape, wherein the plate is shown mounted above the
tunnel floor 35.
[0092] The plate can extend both above and below the operational
depth 71.
[0093] The tunnel side 202, pivot anchors 44a and 44b, parallel
arms 39a and 39b, fender pivots 47a and 47b, and fender 38a are
also shown.
[0094] FIG. 8 shows an embodiment of a dynamic moveable tendering
mechanism formed from a frame 74 instead of the plate. The frame 74
can have intersecting tubulars 75a and 75b that form openings 76a
and 76b for allowing water to pass while water in the tunnel is at
an operational depth 71.
[0095] The tunnel side 202, tunnel floor 35, pivot anchors 44a and
44b, parallel arms 39a and 39b, fender pivots 47a and 47b, and
fender 38a are also shown.
[0096] FIG. 9 shows the tunnel floor 35 having lower tapering
surfaces 73a and 73b at an entrance of the tunnel, providing a
"beach effect" that absorbs surface wave energy effect inside of
the tunnel. The lower tapering surfaces can be at an angle 78a and
78b that is from 3 degrees to 40 degrees.
[0097] Two fenders 38h and 38d can be mounted between two pairs of
parallel arms. Fender 38h can be mounted between parallel arms 39o
and 39p, and fender 38d can be mounted between parallel arms 39g
and 39h.
[0098] In embodiments, the pair of parallel arms can be
simultaneously extendable and retractable.
[0099] The tunnel walls 202 and 204 are also shown.
[0100] FIG. 10 shows a Y-shaped configuration from a top cutaway
view of the hull 12 with the tunnel 30 with the tunnel opening 31,
in communication with a branch 33a and branch 33b going to
additional openings 32a and 32b respectively.
[0101] The buoyant structure can have a transit depth and an
operational depth, wherein the operational depth is achieved using
ballast pumps and filling ballast tanks in the hull with water
after moving the structure at transit depth to an operational
location.
[0102] The transit depth can be from about 7 meters to about 15
meters, and the operational depth can be from about 45 meters to
about 65 meters. The tunnel can be out of water during transit.
[0103] Straight, curved, or tapering sections in the hull can form
the tunnel.
[0104] In embodiments, the plates, closable doors, and hull can be
made from steel.
[0105] FIG. 11 is a side view of the buoyant structure with a
cylindrical neck.
[0106] The buoyant structure 10 is shown having a hull 12 with a
main deck 12a.
[0107] The buoyant structure 10 has an upper cylindrical side
section 12b extending downwardly from the main deck 12a and an
upper frustoconical side section 12g extending from the upper
cylindrical side section 12b.
[0108] The buoyant structure 10 has a cylindrical neck 8 connecting
to the upper frustoconical side section 12g.
[0109] A lower frustoconical side section 12d extends from the
cylindrical neck 8.
[0110] A lower ellipsoidal section 12e connects to the lower
frustoconical side section 12d.
[0111] An ellipsoid keel 12f is formed at the bottom of the lower
ellipsoidal section 12e.
[0112] A fin-shaped appendage 84 is secured to a lower and an outer
portion of the exterior of the ellipsoid keel 12f.
[0113] FIG. 12 is detailed view of the buoyant structure with a
cylindrical neck.
[0114] The buoyant structure 10 is shown with the cylindrical neck
8.
[0115] A fin-shaped appendage 84 is shown secured to a lower and an
outer portion of the exterior of the ellipsoid keel and extends
from the ellipsoid keel into the water.
[0116] FIG. 13 is a cut away view of the buoyant structure with a
cylindrical neck in a transport configuration.
[0117] The buoyant structure 10 is shown with the cylindrical neck
8.
[0118] In embodiments, the buoyant structure 10 can have a pendulum
116, which can be moveable. In embodiments, the pendulum is
optional and can be partly incorporated into the hull to provide
optional adjustments to the overall hull performance.
[0119] In this Figure, the pendulum 116 is shown at a transport
depth.
[0120] In embodiments, the moveable pendulum can be configured to
move between a transport depth and an operational depth and the
pendulum can be configured to dampen movement of the watercraft as
the watercraft moves from side to side in the water.
[0121] FIG. 14 is a cut away view of the buoyant structure 10 with
a cylindrical neck 8 in an operational configuration.
[0122] In this Figure, the pendulum 116 is shown at an operational
depth extending from the buoyant structure 10.
[0123] While these embodiments have been described with emphasis on
the embodiments, it should be understood that within the scope of
the appended claims, the embodiments might be practiced other than
as specifically described herein.
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