Patent Description:
The use of marine power plants on floating vessels to provide underwater operations are well known. Generally, the power plant is located under the water level during operation. It must be lifted out of the water for servicing, transportation and berthing.

Underwater operations include for example and without limitation, underwater surveying, measurement, excavations and dredging.

Furthermore, energy through tidal power may be generated by attaching underwater turbines to floating vessels.

The interest and demand in generating energy from renewable sources is increasing. One renewable source of energy is the tidal movement of large bodies of water generating regular, predictable flows. Economies and practicalities point to submerged turbines as a promising way of extracting energy from the moving water in cost effective manner.

One way of constructing underwater power plant is to attach turbines to floating vessels via movable links to keep the turbines underwater at specified depth and position to utilise the flows and to allow lifting the turbines out of the water for servicing, transport and berthing.

The prior art includes a number of floating assemblies used for generating energy through tidal power.

<CIT> discloses one such complex floating apparatus.

<CIT> describes an arrangement with turbines attached to floating vessel via links hinged at their connection to the vessel and midway between turbine and vessel. All hinges have horizontal axes parallel to the longitudinal axis of the main floating vessel.

Rotation around the vessel-side hinge allows the lowering and raising of the turbines while relative rotation around the mid-link hinge allows the turbines being moved close to the body of the vessel at or just above the water level.

This system allows the reduction of draft to that of the vessel but the beam is still governed by the length of turbine blades. The overall stability of the plant in the service position with turbines lifted out of the water is ensured by using buoyancy members attached to the main body of the vessel. The design, construction and operation of the hinges is complex.

<CIT> describes a similar apparatus. Rather than use buoyancy members attached to the main body of the vessel, one central hull is used to make up the floating vessel which keeps the turbines on the water surface semi submerged in their raised position. An optional second hinge system near the hull vertical axis is disclosed which enables rotation of the link element into a position close to and parallel with the floating vessel, semi submerged. This vertical hinge would replace the mid link horizontal axis hinge. The overall stability of the apparatus is provided by keeping the nacelles partially submerged even in the raised position.

This solution reduces the draft of the assembly to about the same as the draft of the floating vessel and the beam to a width governed by the size of the nacelle and the width of the link element rather than the length of the turbine blades, the overall beam being less than that of the assembly described in <CIT>.

The apparatus described in <CIT> comprises several hinges, hydraulics, ropes, floodable buoyancy chambers, electronic sensors and control units which greatly increase the structural, mechanical and electronic complexity of the solution and still provides only limited reduction of beam, leaves nacelles semi submerged and the turbine blades and nacelle are exposed to potential impact damage as they constitute the widest part of the arrangement.

Both <CIT> and <CIT> imply positioning the full power generation system including shafts, gear box/transmission and electricity generator in the nacelle. This increases the size and weight of the nacelle with the consequential larger stream forces acting on nacelle, linking element and hinges, requiring more robust and powerful moving mechanisms and concerns of overall stability when nacelles are lifted out of the water.

<CIT> discloses a floating platform capable of supporting a turbine assembly. The platform and turbine assembly may be configured to absorb drag. A pivoting cable may be incorporated in the turbine assembly whereby the turbine assembly is moveable and thereby able to absorb drag that is exercised upon a non-moveable rigidly positioned turbine as excessive torque on the turbine rotors. The turbine assembly is pivotable between vertical (working) and horizontal (transportable) positions.

Some of the aims in developing the above solutions is to eliminate the need for special sea vessels for installation and maintenance; to reduce the draft and beam of the floating apparatus in berthing or towing and to raise the nacelle out of the water as much as possible for ease of on-site service and transportation.

The Applicant believes there remains the need for a simpler and safer apparatus and system to achieve the above goals.

The present invention seeks to provide such a system which allows movement of the operating unit (underwater plant) from specified position underwater (its operating position) to another specified point above water, next to body of the host vessel (a service position) by adopting an inclined hinge around which the link element holding the operating unit rotates. This results in the operating unit travelling in an inclined plane from one position to the other. The exact location and inclination of the hinge axis and the length of the link element are designed to place the operating unit into the desired positions.

The present invention also seeks to provide an improved assembly whose layout and construction of the hinge is in two parts both aligned on the same axis, one attached directly to the main vessel - internal side, the other via a hinge support structure - external side.

The present invention also seeks to provide an improved assembly that utilises props to stabilise the link element and operating plant in the operating position.

The present invention also seeks to provide an improved assembly that has a link element formed in two parts (upper and lower) having a common longitudinal axis and allowing rotation of the lower part around the longitudinal axis.

The present invention also seeks to provide an improved assembly that includes a movable/extendable access deck installed in a manner to avoid the path of the link element and operational unit and serving as protection to the nacelles while towing or berthing takes place.

At least one embodiment will now be described by way of example only with reference to the accompanying figures in which:.

In the following description the link element will also be referred to as 'leg' and the host vessel as 'main body', 'floating vessel' or 'hull'.

Individual component descriptions, referring to reference numerals in the figures, are provided at the end of this description.

For the purposes of the description, the following letter references are provided to indicate various and specific axes.

Moreover, reference letters for notable points and angles are provided below.

<FIG> a illustrates an axonometric view of example embodiment, showing the main components floating vessel <NUM>, two part link element <NUM>/<NUM> propped against vessel <NUM> by props <NUM>, main pins <NUM> and the operating unit/plant <NUM> attached to link <NUM>; also in service position.

The figure shows the floating vessel <NUM> on the surface <NUM> of a body of water <NUM> with upper end of legs <NUM> attached via hinges <NUM>. Operating unit <NUM> is attached to the lower end of leg <NUM> in the operating position XA/YA and in the service position XB/YB. Props <NUM> attached to legs <NUM> via hinges <NUM> connect to main body <NUM> in the operating position via releasable connection plates <NUM> and fold against legs <NUM> in the service position. The external/upper end of hinges <NUM> are supported by the hinge support structure <NUM>. The leg support structure <NUM> holds and secures legs <NUM> in the service position XB/YB.

<FIG> illustrates an axonometric view of the notable points and axes. The primary points and axes being W and Z rotational axes, XA and YA link axes in operating position and XB and YB in service position.

It can be seen from <FIG> that the main longitudinal axis U of vessel <NUM> and the vertical axis V intersect at point O. The axes XA and YA of legs <NUM>/<NUM> in the operating position intersect vertical axis V in point A. Leg axes XA and YA rotate around hinge centre points B and C into the service position XB and YB.

Aligning axes W and Z in a plane normal (perpendicular) to the main longitudinal axis U results in axes XB/YB being parallel to axis U when they reach horizontal position. Axes Wan Z can be slightly rotated around axis V whereby YA would move into position YAC, W into WC, point C into position CC and consequently axis YB into YBC at an angle to U, the further away from point CC the greater the distance between YBC and U.

<FIG> illustrates a typical cross section of the embodiment in operating position, showing main elements. This is a typical proposed cross section of the arrangement showing the top and lower part of legs <NUM>/<NUM> in operating position. Pin support structure legs <NUM> hold the top part <NUM> which in turn holds the external part/main hinge housing <NUM>. An access platform <NUM> is positioned under the top part of leg <NUM>. Lower part of the leg <NUM> connects to operational unit <NUM>. Props <NUM> connect to legs <NUM> via hinge pins <NUM> and to main body <NUM> via connection plates <NUM> and connection pin <NUM> held by connection plate <NUM>. Props <NUM> are secured to legs <NUM> through prop top connection plate <NUM> while props move between operating - P/Q and R/S - and service positions. The on-board plant <NUM> is located inside the main body <NUM>. Intersection of main hinge axes W and Z is at point O.

<FIG> illustrates a side view of the embodiment in operating position, showing main elements and ropes and winches for moving the links <NUM>/<NUM> and props <NUM> from one position to another.

Leg <NUM>/<NUM> held in operating position by props <NUM> connecting to leg <NUM> via connection plates <NUM> and <NUM> and pin <NUM>. Top end of props <NUM> connect to hull <NUM> via connection plates <NUM> which is locked in place by locking rods <NUM>. Top end of leg <NUM> held by main pin <NUM> supported by external part of pin support structure <NUM>. Operating plant <NUM> is attached to lower end of leg <NUM>. Leg <NUM> is moved by counter operation of leg moving ropes <NUM> and <NUM> connecting to leg <NUM> via rope connection plate <NUM> and winches <NUM> and <NUM> mounted on the leg support structure <NUM> and vessel deck <NUM>. Props are moved to/from legs <NUM> by the leg side control ropes <NUM> connecting props <NUM> via connection plates <NUM>, and the hull side control ropes <NUM> which are moved by the hull side prop control winches <NUM>. Leg support structure <NUM> is positioned on the main body <NUM> such that it can secure legs <NUM>/<NUM> in the service position via connection plates <NUM> and <NUM>. Platform <NUM> has discontinuities to allow locking rods <NUM> and hull side ropes <NUM> being laid out along the side face of main vessel <NUM>. Access ladders <NUM> connect the floating vessel top deck <NUM> to access platforms <NUM>.

<FIG> illustrates a top view (plan view) of the arrangement in operating position.

<FIG> illustrates a potential utilisation indicated by end view of arrangement showing mechanical gear-shaft drive train from turbine gear wheel <NUM> located in nacelle <NUM> to main axis gear wheel <NUM> of on-board plant <NUM>.

Torque is transmitted from turbine blades <NUM> via the chain of turbine horizontal axis gear wheel <NUM>, inclined axis gear wheel <NUM>, lower end of drive shaft <NUM>, drive shaft splice <NUM>, upper end of drive shaft <NUM>, inclined axis top end gear wheel <NUM>, inward axis top end gear wheel <NUM>, inward axis drive shaft <NUM> and inward axis lower gear wheel <NUM> connecting to main plant gear wheel <NUM>.

<FIG> illustrates one embodiment of the main hinge arrangement showing components of main hinge, attachment method and potential utilisation with gear-shaft drive train schematically. The main hinge is accomplished by cylindrical bearings with flanges, <NUM>/<NUM> on the hull side and <NUM>/<NUM> on the external side.

The essence of the hinges are cylindrical flanged bearings <NUM>, <NUM>, 245and <NUM>. Bearings <NUM> and <NUM> fit into one another, the mating face <NUM> allows smooth rotation along the axis Z. Bearings <NUM> and <NUM> are similar. Flanges are at the opposite ends, flanges of <NUM> and <NUM> connect to outer face of leg connection plates <NUM>, flanges of <NUM> and <NUM> connect to pin support structure <NUM> and hull side mounting plate <NUM> respectively. Mounting plate <NUM> is
attached to main hull <NUM> via connection plates <NUM> and <NUM>. Guide angles <NUM> and <NUM>, attached to connection plate <NUM> and pin support <NUM> extend in a circular fashion engaging with and supporting stiffener plates <NUM> as leg <NUM> rotates around axis Z. This arrangement allows the transfer of forces from leg <NUM> to the structure of the vessel <NUM>.

Potential utilisation with gear-shaft drive train would have shaft <NUM> in leg <NUM> fitted with bevel gear <NUM>. Shaft <NUM> would be held by thrust bearing <NUM> on mounting <NUM> attached to mounting plate <NUM>. Internal faces <NUM> and <NUM> of bearings <NUM> and <NUM> are to be suitable to provide for continuous rotation of inclined shaft <NUM>, driven by bevel gear <NUM> engaging with gear <NUM>. Inclined shaft would be supported by bearings <NUM> and <NUM> attached to plates <NUM> and <NUM>, connected to main on-board plant via plates <NUM> and <NUM> and to inside face of hull structure <NUM> via plates <NUM> and <NUM>. Gear <NUM> at the inside end of shaft <NUM> drives main plant gear wheel <NUM>.

Longitudinal forces on shaft <NUM> are transmitted to bearings <NUM> and <NUM> via thrust bearings <NUM> and <NUM> attached to shaft <NUM>.

<FIG> illustrates the embodiment of the main hinge arrangement of <FIG> with link <NUM> in service position, showing potential utilisation with gear-shaft drive train between nacelle (<NUM>) and on-board plant (<NUM>).

Component parts of pin support structure (<NUM>), leg <NUM> , top part <NUM> and external part <NUM> are shown in addition to parts described in <FIG>.

<FIG> illustrates an embodiment, for illustration purposes, which is not part of the claimed invention, wherein the main hinge arrangement, leg <NUM> in operating position, showing potential utilisation with hydraulic drive train between nacelle (<NUM> ) and on-board plant (<NUM>).

The opening through internal bearing <NUM> is utilised to carry in hydraulic pipes <NUM> serving power transfer between the nacelle (<NUM>) and the on-board power plant (<NUM>).

<FIG> illustrates an embodiment of leg-prop connection via hinge pin <NUM>. Left side of section shows prop <NUM> in operating position, right side shows it in service position.

Leg connection plates <NUM> are attached to leg <NUM> , prop side connection plates <NUM> to prop <NUM>. Stiffener plates <NUM> strengthen the prop and end plate <NUM> closes the prop against water ingress. Props pivot around leg-prop pin <NUM> between service and operating positions.

<FIG> illustrates an embodiment showing side view of the upper leg-prop connection in service position, prop <NUM> folded and secured against leg <NUM> , with prop side leg connection plate <NUM> connected to leg side plate <NUM>. Connection pin <NUM> attached to legs side connection plate <NUM> engages with prop side connection plate <NUM> via hole <NUM> and holds plates <NUM> and <NUM> together.

Leg side control rope <NUM> connecting to prop connection plate <NUM> with shackle <NUM> runs guided by rope roller <NUM> mounted on frame <NUM> to rope winch <NUM> held by frame <NUM>. Guide <NUM> attached to leg <NUM> ensures prop <NUM> is in the correct position and connection plates <NUM> and <NUM> meet face to face.

Two main hull connection plates <NUM> with slots <NUM> are attached to top of prop <NUM>. End plate <NUM> closes the prop against water ingress.

Hull side control rope <NUM> connecting via shackle <NUM> and hole <NUM> runs on side of main hull (<NUM>) to winch (<NUM>).

<FIG> shows the side view of the upper leg-prop connection in service position with alternative embodiment of prop-hull connection, connection plate <NUM> attached to prop <NUM> to connect to main hull (<NUM>).

In the alternative solution the two connection plates <NUM> are replaced by alternative connection plate <NUM> , having guide nibs <NUM> and holes <NUM>.

<FIG> illustrates two embodiments with plates <NUM> and <NUM> of the prop-hull connection in end elevation of service position. The figure shows section of upper leg-prop connection in service position, alternative main hull connection on the left side.

Prop <NUM> is held in place by pin <NUM> going through holes <NUM> and <NUM> in plates <NUM> and <NUM> respectively. Pin <NUM> held in place by spring <NUM> connecting plate <NUM> attached to pin <NUM> to connection plate <NUM>. Main hull connection plate <NUM> with guide nib <NUM> and shear pin holes <NUM> are shown. Top leg-prop connection is same for preferred connection layout, not shown.

Guide <NUM> ensures prop side connection plate <NUM> moves towards leg side plate <NUM> while being pulled up by control rope (<NUM>).

Right side shows a version of two prop-hull connection pates <NUM> being attached to prop <NUM>, leg mounted upper rope winch <NUM> and its frame <NUM> with control rope <NUM> and shackle <NUM> attached to leg-prop connection plate <NUM>.

<FIG> illustrates in enlarged detail, the leg-prop connection locking mechanism with spring <NUM> and pin <NUM>. Pin <NUM> is capable of sliding in hole <NUM> and socket <NUM> while being attached to spring <NUM> via push plate <NUM>. Spring <NUM> is connected to plates <NUM> and <NUM> and holds pin <NUM> engaged with plates <NUM> and <NUM> preventing relative movement between the two but allows pin <NUM> being withdrawn to disengage from plate <NUM> thus allowing prop (<NUM>) to move away from leg <NUM>.

<FIG> illustrates, in enlarged detail of the leg-prop connection locking mechanism with bolt <NUM>. Pin <NUM>, push plate <NUM>, socket <NUM> and spring <NUM> are being replaced by bolt <NUM>.

<FIG> shows a side view of embodiment of prop-main hull connection with prop <NUM> near operating position with main connection plate <NUM> and pin <NUM>. Top end of prop <NUM> has end plate <NUM>, two main connection plates <NUM> with slot <NUM> in each, rope and leg connection plate <NUM> with connection holes <NUM> and <NUM>, control ropes <NUM> and <NUM> attached. Main connection plate <NUM> is parallel to the plane in which prop <NUM> moves while pivoting around leg-prop hinge (<NUM>). Hull side of connection composed of plates <NUM> holding main connection pin <NUM> and inclined guide plate <NUM>, attached to main body <NUM>. Locking rod <NUM> is threaded through bracket <NUM> shown in the service position. Bracket <NUM> has plate with threaded hole through which locking rod <NUM> can be threaded up and down to lock or unlock plate <NUM>. Control rope <NUM> is lead through control rope roller <NUM> held by frame <NUM> attached to main body <NUM>. Guide plate <NUM> and guide frame <NUM> ensure main connection plate <NUM> engages connection pin <NUM> in correct position.

<FIG> shows a side view of embodiment of prop-main hull connection with prop <NUM> in the operating position with main connection plate <NUM> engaging pin <NUM> and locking rod <NUM> locking plate <NUM> in position. Locking rod <NUM> locks prop <NUM> into position by being threaded through bracket <NUM> till it reaches the top of main connection plate <NUM>. Longitudinal forces from prop <NUM> are transferred through pin slot <NUM> in main connection plate <NUM> , connection pin <NUM> and hull side plate <NUM> to main body <NUM>. Lesser magnitude transverse forces are transferred from main connection plate <NUM> via locking rod <NUM> to bracket <NUM> and from there to hull <NUM>. Control ropes <NUM> and <NUM> connected to leg and rope connection plate <NUM> via shackles <NUM> and <NUM>.

<FIG> illustrates a top view of an embodiment of prop-main hull connection with prop <NUM> in the operating position, with main components plates <NUM> , pin <NUM> and locking rods <NUM>. One locking rod <NUM> is shown in the service position at a distance from main connection plate <NUM> , the other in the operating position engaging with main connection plate <NUM>.

<FIG> shows a section of an embodiment through main connection plates <NUM> , hull side connection plates <NUM> , connection pin <NUM> and guide plates <NUM> in the operating position of prop (<NUM>).

<FIG> is a section through top end of embodiment prop <NUM> in the operating position showing main connection plates <NUM> and guide frames <NUM>.

<FIG> shows the locking rod <NUM> layout on side of main body <NUM> with prop control rope <NUM> and access platform <NUM>. Locking rod <NUM> is guided by brackets <NUM> and <NUM> and has handle <NUM> at top deck <NUM> allowing locking/unlocking prop connection from above. Main connection plates <NUM> and hull side connection plates <NUM> are also indicated as well as control rope roller <NUM>, control rope <NUM> and control rope winch <NUM>.

<FIG> is a side view of the prop-main hull connection with alternative connection plate <NUM>, shear pins <NUM> and locking device <NUM>. Top end of prop has alternative main connection plate <NUM> aligned parallel with leg-prop hinge (<NUM>) and perpendicular to leg and rope connection plate <NUM> and end plate <NUM>. Alternative hull side connection plate <NUM> , attached to main hull <NUM> and stiffened by plate <NUM> holds shear pins <NUM> to engage with pin holes <NUM> in main connection plate <NUM>. In operating position plate <NUM> rests on plate <NUM> , shear pins <NUM> pass through holes <NUM> and engage with locking device <NUM> clamping plates <NUM> and <NUM> together. Movement of prop <NUM> towards main body <NUM> is guided by main connection plate guide nib <NUM> sliding within alternative connection guide channel <NUM>.

Control rope hole <NUM> in plate <NUM> allows the threading through of control rope <NUM>. Rollers <NUM> held by roller frames <NUM> lead control rope <NUM> towards winch <NUM>.

<FIG> shows an alternative prop-hull connection showing plan view and section, with main connection plates <NUM>, <NUM> and shear pins <NUM> as main components. The figure shows hull side connection plate <NUM> with stiffener plates <NUM>, shear pin holes <NUM>, control rope hole <NUM> attached to main body <NUM> and guide channels <NUM> attached to connection plate <NUM>. Plan details show main connection plate <NUM> with guide nib <NUM> and pin hole <NUM> engaging with guide channel <NUM> and shear pin <NUM> respectively. Section shows main connection plate <NUM>
and hull side connection plate <NUM> in operating position, shear pins <NUM> engaged with pin holes <NUM> and locking device <NUM>. Shear pins <NUM> have larger diameter shear body engaging with plate <NUM> and smaller diameter threaded top engaging with locking device <NUM>.

<FIG> shows details of the locking device <NUM>, including main connection plate <NUM> with pin hole <NUM> engaging shear pin <NUM>. Parts of the locking device are frame <NUM> attaching handle <NUM> to main plate <NUM> having clamping cylinder <NUM> and locking nut <NUM> attached to it as well. Main connection plate <NUM> and hull side connection plate <NUM> are locked together by making shear pins <NUM> effective by turning locking device <NUM> to engage locking nut <NUM> with the threaded part of shear pin <NUM> and tightening.

<FIG> is a longitudinal section showing embodiment of upper <NUM> and lower leg <NUM> connection with bearing casings <NUM>/<NUM>, bearings <NUM>/<NUM> and shaft seal bearing <NUM> as main components as well as potential utilisation - Horizontal Axis Tidal Turbine (HATT) with mechanical drive train assumed. Indicative section through nacelle (<NUM> ) and mechanical drive train, taken along turbine axes <NUM>. Upper-lower leg <NUM>/<NUM> connection via top/lower bearing housing <NUM>/<NUM> attached to inside of upper part of leg <NUM> and top/lower bearings <NUM>/<NUM> attached to outside of lower part of leg <NUM> allowing engagement of bearings <NUM>/<NUM> with housing <NUM>/<NUM> and rotation of lower part <NUM> around axes X/Y. Bearings <NUM> and <NUM> are dual action bearings in that they provide for the rotation of lower leg <NUM> and also work as thrust bearings preventing lower leg <NUM> slide up/down along axis X/Y relative to upper part <NUM>. Shaft seal <NUM> attached to lower end of leg <NUM> ensures watertight connection. Potential utilisation for HATT would include nacelle connection flange <NUM> and leg connection flange <NUM> bolted together, main body of nacelle <NUM> connecting to flange <NUM> via attaching 'neck' <NUM>. In potential arrangement turbine blades <NUM> connect to stub shaft <NUM> via connection plates <NUM>. Bulk head <NUM> attaches to main body of nacelle <NUM> and holds shaft bearing <NUM> to effect watertight connection around shaft <NUM>. Bearing support frame <NUM> and bearing <NUM> support the inner end of shaft <NUM>.

Front <NUM> and rear <NUM> nacelle covers rotate with the turbine blades <NUM>. Torque from the rotation of turbine blades <NUM> carried through shaft <NUM> to horizontal axis gear wheel <NUM>, to inclined axis gear wheel <NUM> to shaft <NUM> and through shaft splice <NUM> to upper shaft <NUM>. Thrust bearing <NUM> is held by bearing housing <NUM> attached to lower part of leg <NUM>. Bearing <NUM> attached to lower leg <NUM> via bearing frame <NUM> provides the second point of support for lower shaft <NUM>. Top part of dive shaft <NUM> is supported by bearing <NUM> attached to lower part of leg <NUM> via bearing frame <NUM>. This arrangement allows the rotation of shaft <NUM> and <NUM> around axes X-Y as well as the rotation of lower part of leg <NUM> and nacelle <NUM> relative to upper part of leg <NUM>. This rotation could be driven and controlled by drive unit <NUM> via shaft <NUM> and drive wheel <NUM> engaging with lower part of leg <NUM>.

<FIG> shows a transverse section of the upper-lower leg connection and potential utilisation by HATT with mechanical drive train. Horizontal Axis Tidal Turbine with blades assumed. Indicative section through leg <NUM>/<NUM> taken perpendicular to turbine axes <NUM>. Description of components as above in <FIG>.

<FIG> shows a partial section of upper-lower leg connection and potential utilisation by HATT with hydraulic drive train, showing schematic location of transmission/gear box <NUM> and hydraulic pump <NUM>. Horizontal Axis Tidal Turbine with hydraulic drive train assumed.

Indicative section through nacelle <NUM> taken along turbine axes <NUM> showing potential hydraulic drive train. Leg <NUM> to leg <NUM> and to nacelle <NUM> connections as on <FIG>.

In potential utilisation hydraulic drive train composed of gear box/transmission <NUM> supported on lower/upper mounting frames <NUM>/<NUM> with position adjustment packers <NUM> installed in lower part of leg <NUM> and hydraulic pump <NUM> supported on mounting plates <NUM> and <NUM> with adjustable packer <NUM> installed in upper part of leg <NUM>. Gear wheel <NUM> transfers torque to gear box <NUM> via shaft <NUM>, gear box <NUM> connects to hydraulic pump <NUM> via shaft <NUM> held by bearing <NUM> attached to lower leg <NUM> via bearing frame <NUM>, shaft splice <NUM> and shaft <NUM> held by bearing <NUM> mounted on bearing frame <NUM>. Hydraulic pump <NUM> connects to on board plant via hydraulic pipes <NUM>.

<FIG> is an axonometric view of potential utilisation with HATT in operating position. Horizontal Axis Tidal Turbine with blades assumed. Operating position is shown with leg <NUM>/<NUM> secured in position by props <NUM> connecting to main body <NUM> and holding nacelle <NUM> and turbine blades <NUM> under the water surface <NUM> and away from main body <NUM>.

Leg control ropes <NUM> and <NUM> connect to winches <NUM> and <NUM> respectively, top prop control ropes <NUM> connect to leg <NUM> and top of prop <NUM>, lower control ropes <NUM> connect to winches <NUM>. The external end of main hinges <NUM> are held by the pin/hinge support structure <NUM>, leg support structure <NUM> is not connected to leg <NUM> in this position.

<FIG> is an axonometric view of potential utilisation with HATT in transition between operating and service positions. Horizontal Axis Tidal Turbine with blades assumed.

The legs <NUM> and <NUM> are in transition between operating and service positions. Turbine blades <NUM> are aligned with leg <NUM> and props <NUM> are folded and secured to legs <NUM>. Movement towards leg support structure <NUM> achieved by winch <NUM> pulling leg <NUM> while winches <NUM> and <NUM> are letting out to allow movement. Movement towards operating position achieved by winch <NUM> puling and winch <NUM> letting out while winches <NUM> are just taking up the slack in the control rope.

<FIG> is an axonometric view of potential utilisation with HATT in service position. Horizontal Axis Tidal Turbine with blades assumed. Legs <NUM> and <NUM> in the service position XB and YB, attached to leg support structure <NUM> via connection plates <NUM> and <NUM>. Turbine blades <NUM> aligned with leg <NUM>. Leg control rope <NUM> is taut, rope <NUM> is slack. Access platform <NUM> indicated.

<FIG> shows an end view of potential utilisation with HATT in operating position. Horizontal Axis Tidal Turbine with blades assumed.

<FIG> shows a side view of potential utilisation with HATT in operating and service position. Horizontal Axis Tidal Turbine with blades assumed.

<FIG> shows a section of potential utilisation with HATT in service position, taken near prop attachment. Horizontal Axis Tidal Turbine with blades assumed. Schematic cross section through legs <NUM> and props <NUM>.

<FIG> illustrates a section of potential utilisation with HATT in service position, taken near leg support structure <NUM>. Horizontal Axis Tidal Turbine with blades assumed.

Schematic cross section near leg support structure <NUM>.

<FIG> illustrates a section of potential utilisation with HATT in service position, taken near nacelle. Horizontal Axis Tidal Turbine with blades assumed. Schematic cross section near nacelle <NUM>.

<FIG> is an end view of potential utilisation with Modified Vertical Axis Tidal Turbine. Modified Vertical Axis Tidal Turbine assumed. The figure shows main body <NUM>, parts of pin support structure <NUM> , <NUM>, <NUM>, legs <NUM>, props <NUM> main on-board plant <NUM> and access platform <NUM>. Vertical turbine <NUM> shown schematically.

<FIG> shows an end section of potential utilisation with Modified Vertical Axis Tidal Turbine, taken through turbine. Modified Vertical Axis Tidal Turbine assumed. Schematic cross section through vertical axis turbine <NUM> in service position.

<FIG> provides schematic detail of potential utilisation with Modified Vertical Axis Tidal Turbine. Modified Vertical Axis Tidal Turbine assumed. Detail section through leg <NUM> showing shaft seal/bearing <NUM>, bulk head/end plate <NUM>, shafts <NUM> and <NUM> with shaft splice <NUM>, thrust bearing <NUM> , thrust bearing housing <NUM>, bearing frame <NUM>, and bearing <NUM>. Vertical Axis Turbine <NUM> shown schematically.

<FIG> shows a longitudinal section through nacelle showing potential utilisation with FIATT and hydraulic drive train, shoving schematic location of low speed hydraulic pump. Horizontal Axis Tidal Turbine assumed. Potential arrangement with low speed hydraulic pump without transmission/gear box. Turbine axis <NUM> coupled to low speed hydraulic pump <NUM> via pump shaft splice <NUM>. Shaft <NUM> also held by bearing <NUM> mounted on bearing frame <NUM> attached to nacelle body <NUM> via bearing frame base <NUM>. Hydraulic pipes <NUM> are held to nacelle body <NUM> and to leg <NUM> by pipe brackets <NUM>.

As previously stated, an objective of the invention is to provide a marine power plant whose assembly allows of movement of the operating unit (underwater plant) <NUM> from specified position underwater (operating position) to another specified point above water and next to body of the host vessel (service position) by adopting an inclined hinge <NUM> around which the link element <NUM> , <NUM> holding the operating unit <NUM> rotates, as can be seen in <FIG>.

This results in the operating unit travelling in an inclined plane from position XA to XB or back. The exact location and inclination angle AL of hinge axes W and Z and the length of the link/keg element <NUM>/<NUM> are designed to place the operating unit <NUM> into the desired positions specified by depth below water surface and distance from body of vessel for the operating and height above water surface and distance from body of vessel for the service positions.

Typically axes V, W, Z, XA and YA are in a plane normal (perpendicular) to the longitudinal axis U, this plane being depicted by points D, E, F, T, G, FI, I, J and K.

The position of point O - intersection of axes W, Z, V and U - is being determined by the size of the on-board plant <NUM> and the position of the internal plant main axis <NUM>, see <FIG> and <FIG>.

Hinge points B and C on axes Z and W are determined such that leg <NUM> and the folded-up props <NUM> are clear of the main body <NUM> in the service position indicated by axes XB and YB, see <FIG>. Space requirements for servicing the operational unit also influence the position of points B and C.

Lateral distance/space for servicing nacelle can be provided by rotating axes W and Z around axis V out of the normal plane. <FIG> shows axis YA in the normal plane and YAC rotated by angle BET around axis V. The horizontal position of link/leg <NUM> is XB corresponding to axis position W and YBC corresponding to axis WC. While this provides more space for the operating unit, it complicates detailing and increases the total width of the unit.

The layout and construction of the main hinge is in two parts, both aligned on the same axis, one attached directly to the main vessel, the other via the hinge support structure. Both hinges are cylindrically shaped allowing a shaft being installed through the two cylindrical openings, aligned on the same axis as the bearings and rotating independently of the link element. This allows for a drive train of shafts and bevel gears from the link element through the hinge into the body of the host vessel. Absence of said drive train and shaft allows pipes and cables being led through the opening.

An embodiment of the above feature is best shown on <FIG>. On the hull side connection plates <NUM> and <NUM>, attached to the main hull <NUM> hold the bearing mounting plate <NUM>. The fixed part of bearing <NUM> is attached to mounting plate <NUM> via its flange in a manner allowing adjustment of position so bearing <NUM> can be lined up with the other bearings <NUM>, <NUM> and <NUM>. The cylindrical part of <NUM> is shaped both on the inside <NUM> and outside <NUM> to provide a bearing surface to shaft <NUM> on the inside and to rotating bearing <NUM> on the outside.

Rotating part <NUM> has bearing surface on the inside of the cylindrical part <NUM> - bearing against the external face of bearing <NUM> - and flange attached to main connection plate <NUM> of link/leg <NUM>.

On the external side the arrangement is similar, fixed bearing <NUM>, attached to hinge support structure <NUM> by its flange, holds shaft <NUM> on the inside through bearing surface <NUM> and rotating bearing <NUM> on the outside via face <NUM>.

Interfaces <NUM>, <NUM>, <NUM> and <NUM> are to be bearing surfaces allowing relative rotation and able to transfer forces acting in the direction of the link/leg <NUM> axis XA.

This arrangement allows shaft <NUM> and link/leg element <NUM> both to rotate around axis Z independently.

Guide angles <NUM> and <NUM> are attached to connection plate <NUM> and hinge support structure <NUM> respectively and extend in a circular shape around axis XA to take up forces acting transversely to link/leg axis XA, transmitted by leg stiffener and guide plates <NUM>.

The above arrangement makes it possible to construct a mechanical shaft-bevel gear -shaft drive train between the operational unit (<NUM>) via shafts (<NUM>) and <NUM> by having a bevel gear <NUM> attached on shaft <NUM> fitting between the main connection plates <NUM> of link/leg <NUM> , engaging with bevel gear <NUM> fitted on shaft <NUM> which has bevel gear <NUM> attached, engaging gear <NUM> of the main on-board plant <NUM>.

Inside the main hull <NUM> there are simple fixed bearings <NUM> and <NUM> with internal face serving as bearing to shaft <NUM> and flanges allowing position adjustment and connection to mounting plates <NUM> and <NUM>, which are in turn attached to connection plates <NUM>, <NUM> and the hull side and <NUM> and <NUM> on the main plant side. The ends of bearings <NUM> and <NUM> serve as thrust bearings against thrust bearings <NUM> and <NUM>. Thrust bearing are necessary as bevel gears generate longitudinal - acting along the shaft - forces which need to be resisted by the arrangement.

The leg side shaft <NUM> has its thrust bearing <NUM> and thrust bearing housing <NUM> at the top of the link/leg element <NUM> , attached to thrust bearing holding plate <NUM>.

The arrangement of bearings <NUM> and <NUM> allows for hydraulic pipes <NUM> of a hydraulic drive train to pass through the central opening of bearing <NUM>, as shown on <FIG>. In this case there are no shafts and gear wheels required and this embodiment is not part of the claimed invention.

Link/leg members <NUM>/<NUM> are moved between service and operating positions by ropes <NUM> and <NUM> attached to winches <NUM> and <NUM> respectively. See <FIG>, <FIG>, <FIG>.

The ropes connect to rope connection plate <NUM> attached to upper leg <NUM> near the leg-prop hinges. One of said winches tightening, the other relaxing would rotate leg <NUM>/<NUM> around main pin <NUM> (axis W or Z). Designing leg <NUM>/<NUM> and operating unit <NUM> in a manner as to achieve close to neutral buoyancy of leg <NUM>/<NUM> and nacelle <NUM> allows easier moving of leg <NUM>/<NUM>.

In service position connection plate <NUM> attached to leg <NUM> and connection plate <NUM> attached to leg support structure <NUM> come in contact and are connected to secure leg <NUM>/<NUM> in the service position. This can be done simply by bolting them together. See <FIG> and <FIG>.

Props are used to stabilise the link element and operating unit in the operating position. The props are attached to link element via hinges aligned at a suitable angle and connect to main body of vessel via releasable connection. In service position and during transition from one
position to other props are disconnected from main vessel, folded and secured against link/leg element.

Prop-leg connection hinges <NUM> to be positioned such to avoid interference with the working of the operating unit. See <FIG>, <FIG> and <FIG>. Point L - see <FIG> -is at the intersection of link axis XA and prop axes P and Q. Link-prop hinge pins <NUM> are located above point L on axes P and Q. Props <NUM> rotate around hinge pin <NUM> in the LBM and LBN planes.

Connection points M and N are to be located such that the angle between link/leg <NUM> and prop <NUM> is approximately <NUM> degrees in plan - see <FIG> - and as large as possible in end view - see <FIG> with angle marked GAM on <FIG> b. The location also must ensure that prop ends can reach the connection point and devices by being rotated from leg <NUM> towards hull <NUM>, without hitting the side of the hull. <FIG> shows leg-prop connection pins <NUM>, leg and prop side connection plates <NUM> and <NUM> , end plate <NUM> and stiffener plate <NUM>.

The top end of props <NUM> has releasable connection to link/leg <NUM> ensuring a fixed position is maintained while link/leg <NUM> rotates from service to operating position or back.

<FIG> shows one embodiment where the position of the prop <NUM> is changed and controlled by rope <NUM> attached to winch <NUM> mounted onto frame <NUM> attached to leg <NUM> , and rope <NUM> attached to winch (<NUM>) mounted on deck of hull <NUM>. Guide frame <NUM> attached to link/leg <NUM> ensures prop <NUM> is in required position when rope <NUM> tightened and prop end connection plate <NUM> comes to contact with leg side plate <NUM> allowing locking pin <NUM> attached to plate <NUM> pass through hole <NUM> and hold prop <NUM> in a fixed position in relation to leg <NUM>.

The prop-hull connection is accomplished by main connection plate <NUM> having cut <NUM> allowing engagement with connection pin (<NUM>) attached to main hull (<NUM>) as prop <NUM> is rotated around pin <NUM>. Plates <NUM> are parallel to plane BLM or BLN in which centreline P/Q of props <NUM> moves. Pins <NUM> and <NUM> are oriented perpendicular to this plane (see also <FIG>).

<FIG> shows prop-leg connection with an alternative embodiment of prop-hull connection plate <NUM> having guide nib <NUM> and shear pin holes <NUM>. Connection plate <NUM> is perpendicular to planes BLM and BLN.

The end view of both configurations is shown on <FIG> giving details of locking pin <NUM> attached to push plate <NUM> and spring <NUM> connecting plates <NUM> and <NUM> in a manner as keeping pin <NUM> being engaged by plates <NUM> and <NUM> but allowing the temporary withdrawal of pin to release plate <NUM>. Guide <NUM> ensuring plates <NUM> and <NUM> meet is also shown. Ropes <NUM> and <NUM> connect to plate <NUM> via shackles <NUM> and <NUM> respectively.

Alternatively, plates <NUM> and <NUM> can be connected by bolt <NUM> for the transition as shown on <FIG>.

When link/leg <NUM>/<NUM> reaches operating position after moving from position XB/YB to XA/YA, withdrawing locking pin <NUM> or un-installing bolt <NUM> releases prop <NUM> from its locked position. Pulling in rope <NUM> with winch (<NUM>) while keeping rope <NUM> tight but letting will move prop <NUM> towards its operating position, top end approaching hull <NUM>. See <FIG> and <FIG>, <FIG>, <FIG> and <FIG>.

Connection of prop <NUM> to hull <NUM> is accomplished by slots <NUM> in main prop connection plates <NUM> engaging with pins <NUM> held by plates <NUM> connected to main hull <NUM>. Plates <NUM> provide side support to plates <NUM> as well. See <FIG> - prop <NUM> approaching hull <NUM>, and <FIG> and <FIG> - Plate <NUM> and pin <NUM> engaged. Guides <NUM> guide the main body of props <NUM> while inclined guide plates <NUM> guide the prop connection plates <NUM> to between plates <NUM>.

Threaded locking rods <NUM> driven through threaded holes in brackets <NUM> lock plates <NUM> in operating position by preventing lift up and disengagement from pin <NUM>. Threaded locking rods <NUM> extend to the deck of the main hull <NUM> allowing operations from above, as the connection is expected be under water due to its low position.

When the connection is due to be released, threaded locking rods <NUM> are wound up allowing plates <NUM> move upwards and disengage from pins <NUM>. Tightening winches <NUM> while relaxing winches <NUM> will move props <NUM> towards link/leg <NUM> allowing securing for transition as described above.

Alternative embodiment of connection between props <NUM> and hull <NUM> is accomplished by adopting connection plate <NUM> in position perpendicular to planes BLN and PLM. Hull side connection plate <NUM> has same orientation and they match when prop <NUM> is in correct position. The force transfer is accomplished by shear pins <NUM> being attached to hull side connection plate <NUM> engage pin holes <NUM> in prop side connection plate <NUM>. See <FIG> and <FIG>.

Shear pins <NUM> are attached to plate <NUM> in a manner strong enough to resist calculated shear forces. Their large diameter base engages through the thickness of plate <NUM> providing shear and bearing resistance and smaller diameter threaded end engages with the threaded plate/locknut <NUM> of locking device <NUM>. See <FIG> for details of locking device.

Prop end connection plates <NUM> are being guided into position by guide nibs <NUM> sliding in guide channels <NUM> attached to plates <NUM>.

The link elements are formed in two parts (upper and lower) having a common longitudinal axis and allowing rotation of the lower part around the longitudinal axis.

One embodiment of this feature is accomplished by forming upper leg <NUM> and lower leg <NUM> using circular hollow sections, upper leg <NUM> is larger in diameter to allow bearings <NUM>, <NUM> and bearing housing <NUM>, <NUM> being installed between upper and lower parts <NUM>/<NUM>. Lower part <NUM> extends suitable distance inside upper part <NUM> to provide adequate strength to the connection against forces acting on operating unit (<NUM>) and lower part of leg <NUM>. The gap between lower <NUM> and upper <NUM> parts is sealed by shaft bearing <NUM> rendering the inside of upper part <NUM> waterproof.

Controlled rotation of lower part <NUM> and operational unit (<NUM>) is achieved by drive unit <NUM> installed inside the upper leg <NUM> above the top end of lower leg <NUM>, driving wheels <NUM> via drive shafts <NUM>. Drive wheels <NUM> engage top of lower leg <NUM> and rotate it in a controlled manner. It is envisaged that without drive unit <NUM> operational unit (<NUM>) and lower leg <NUM> would be free to rotate.

In case mechanical drive train is to be installed lower shaft <NUM> and upper shaft <NUM> would be joined by shaft splice <NUM> to allow for method of assembly. Shafts <NUM> and <NUM> would be held by thrust bearing <NUM> and rotational bearings <NUM> and <NUM> held by bearing frames <NUM>, <NUM> and <NUM> , attached to inside of lower leg <NUM>.

A movable and/or extendable access deck <NUM> installed in a manner to avoid the path of the link element and operational unit. See <FIG>, <FIG>.

The fixed part is designed to fit under the path of leg <NUM>/<NUM> and props <NUM> and allow extension to provide full width and side protection in the service position to nacelle and other components.

Potential utilisations of the invention are depicted on <FIG>, <FIG> and <FIG> showing horizontal axis tidal turbine (HATT) as the operational unit with mechanical drive train from turbine to on board plant (generator). <FIG> indicates the potential arrangement for HATT using hydraulic drive train instead of mechanical. Hydraulic pump <NUM> would be positioned above the top end of lower leg <NUM>, connecting to transmission/ gear box <NUM> via shafts <NUM>, <NUM>, shaft splice <NUM> and shaft <NUM>. It is anticipated transmission/gear box <NUM> would increase the rotational speed adequate for hydraulic pump <NUM>. This arrangement allows controlled or free turn around rotation of lower leg <NUM> and operational unit (<NUM>) relative to upper leg <NUM>.

Axonometric views of potential HATT utilisation are shown on <FIG>, <FIG>, end and side views of same on <FIG> a and <NUM> b, sections on 12a, 12b, 12c.

Potential utilisation with modified vertical axis tidal turbine is indicated on <FIG> and <FIG>.

Potential nacelle arrangement schematic with utilisation of low speed hydraulic pumps to create the hydraulic drive train is shown on <FIG>. This arrangement would require controlled rotation of lower leg <NUM> and nacelle (<NUM>) as the hydraulic pipes/hoses would not allow continuous rotation in one direction, rotation would have to be allowed in both directions with limited extent and controlled actively by drive unit.

An assembly and system described provides a number of benefits over other known assemblies.

The operating unit can be moved next to the main vessel and mostly above water, reducing beam and draft of vessel in the servicing stage.

Servicing the operational unit can be carried out from fixed or movable platforms attached to the main vessel.

The construction of the link element is simple, commercially available sections (large diameter pipes) can be considered.

Moving the operating unit from one position to the other is being accomplished by ropes and winches, avoiding the need for complex hydraulics.

The arrangement and formation of the hinge opens up the possibility of using mechanical drive train from/to the operating unit to/from the on-board plant (generator/engine) located in the main buoyancy vessel rather than in the nacelle.

The mechanical drive train can be adopted to suit the application of vertical axis turbines and make their construction simpler.

The arrangement suits the application of hydraulic drive train between the operating unit and on-board plant.

The use of mechanical or hydraulic drive trains with the generator being positioned in the main vessel offers the possibility of the blades and nacelle being fully above the water in the service position.

Adopting mechanical or hydraulic drive trains to place the main plant on board the main vessel simplifies design, construction operation and servicing.

The simpler structural arrangement allows for simpler control system, electronic, hydraulic and mechanical.

Claim 1:
A marine plant assembly comprising:
a floating vessel (<NUM>);
a plant operating unit (<NUM>) attached to the floating vessel (<NUM>) in such a way that the operating unit is at least partially submerged during operation;
at least one link element (<NUM>) providing an inclined hinged connection (<NUM>) between the operating unit (<NUM>) and the floating vessel (<NUM>), thereby to allow movement of the operating unit from its submerged operating position to above the water level and adjacent the floating vessel (<NUM>) by said link element (<NUM>) rotating about an inclined axis into a position substantially parallel to the floating vessel (<NUM>);
wherein the hinged connection (<NUM>) includes two pairs of cylindrical bearings (<NUM>, <NUM>, <NUM>, <NUM>) aligned on a common inclined axis and being able to rotate relative to one another about the common axis, a first cylindrical bearing of each pair being attached secured to a connection plate (<NUM>) which in turn is secured to the link element (<NUM>), and the second of each pair being indirectly secured to the floating vessel (<NUM>);
wherein each pair of cylindrical bearings (<NUM>, <NUM>, <NUM>, <NUM>) has a first central shaft (<NUM>) extending therethrough, the first central shaft having a rotation transmitting device secured thereto to rotate the first central shaft about the common axis independent of the bearings.