Floating windmill installation

1. A floating windmill installation ( 1 , 1 ′, 1 ″), comprising:

a windmill ( 10 , 10 ′) comprising a tower ( 14 ),

a floating installation ( 20 , 20 ′) comprising an aperture ( 22 ) penetrating the floating installation ( 20 , 20 ′) for accommodating the tower ( 14 ), and

means for raising and lowering the tower ( 14 ) up and down through the aperture ( 22 ),

wherein the tower ( 14 ) comprises a conical section ( 14 c ), and the aperture ( 22 ) comprises a mating conical portion ( 22 c ), wherein the conical section ( 14 c ) is arranged to abut the mating conical portion ( 22 c ) when the tower ( 14 ) is moved a distance up in the aperture ( 22 ) due to an upward directed force from an increase in buoyancy of the tower ( 14 ), and the floating installation ( 20 ) is affected by means for a downward directed force keeping the floating installation submerged at a first depth,

wherein the upwards directed force is equal to the downward directed force when the floating installation ( 20 ) is at a first depth and the upward directed force overcomes the downward directed force when the floating installation ( 20 ) is moved by the upward directed force of the tower ( 14 ) to a second shallower depth,

wherein said means for the downward directed force on the floating installation ( 20 ) is a mooring system ( 40 ) comprising an anchor ( 42 ), a mooring line ( 41 ) and a mooring weight ( 43 ), wherein the mooring weight ( 43 ) is connected to the mooring line ( 41 ) at a point between the anchor ( 42 ) and the floating installation ( 20 ), so that when the floating installation ( 20 ) is at a the first depth the mooring weight ( 43 ) will rest on the seafloor ( 4 ), and when the floating installation ( 20 ) is at a the second shallower depth, the mooring weight ( 43 ) will be suspended above the seafloor ( 4 );

wherein the means for raising or lowering the tower ( 14 ) comprises pitch rack, gears and motor for providing movement.

2. The floating windmill Installation ( 1 , 1 ′, 1 ″) according to claim 1 , wherein the means for raising and lowering the tower ( 14 ) comprises one or more ballast tanks ( 31 ) in the tower ( 14 ) adapted to receive and hold fluid.

3. The floating windmill installation ( 1 , 1 ′, 1 ″) according to claim 2 , wherein the floating windmill installation ( 1 , 1 ′, 1 ″) comprises a system for pressurized air or gas for displacing fluid out of one or more of the one or more ballast tanks ( 31 , 35 ).

4. The floating windmill installation ( 1 , 1 ′, 1 ″) according to claim 2 , wherein the floating windmill installation ( 1 , 1 ′, 1 ″) comprises a connection point for connecting an external supply of fluid for filling or receiving fluid from the one or more ballast tanks ( 31 , 35 ).

5. The floating windmill installation ( 1 , 1 ′, 1 ″) according to claim 1 , wherein the floating installation ( 20 , 20 ′) comprises a ballast tank ( 35 ) adapted to receive and hold fluid to be used as ballast to lower and raise the floating installation ( 20 , 20 ′) in the surrounding water ( 6 ).

6. The floating windmill installation ( 1 , 1 ′, 1 ″) according to claim 1 , wherein the floating windmill installation ( 1 , 1 ′, 1 ″) comprises a connection point for connecting to an external supply of pressurized air or gas, for displacing liquid ( 33 , 36 ) out of the one or more ballast tanks ( 31 , 35 ).

7. The floating windmill installation ( 1 ′) according to claim 1 , wherein the floating installation ( 20 ′) comprises a blade storage space ( 26 ) for storing one or more blade ( 13 ).

8. The floating windmill installation ( 1 ′) according to claim 7 , wherein the blade storage space ( 26 ) is adapted for storing one or more blades ( 13 ) in a vertical orientation.

9. A floating windmill installation ( 1 , 1 ′, 1 ″), comprising:

a windmill ( 10 , 10 ′) comprising a tower ( 14 ),

a floating installation ( 20 , 20 ′) comprising an aperture ( 22 ) penetrating the floating installation ( 20 , 20 ′) for accommodating the tower ( 14 ), and

means for raising and lowering the tower ( 14 ) up and down through the aperture ( 22 ),

wherein the tower ( 14 ) comprises a conical section ( 14 c ), and the aperture ( 22 ) comprises a mating conical portion ( 22 c ), wherein the conical section ( 14 c ) is arranged to abut the mating conical portion ( 22 c ) when the tower ( 14 ) is moved a distance up in the aperture ( 22 ) due to an upward directed force from an increase in buoyancy of the tower ( 14 ), and the floating installation ( 20 ) is affected by means for a downward directed force keeping the floating installation submerged at a first depth,

wherein the upwards directed force is equal to the downward directed force when the floating installation ( 20 ) is at a first depth and the upward directed force overcomes the downward directed force when the floating installation ( 20 ) is moved by the upward directed force of the tower ( 14 ) to a second shallower depth,

wherein said means for the downward directed force on the floating installation ( 20 ) is a mooring system ( 40 ) comprising an anchor ( 42 ), a mooring line ( 41 ) and a mooring weight ( 43 ), wherein the mooring weight ( 43 ) is connected to the mooring line ( 41 ) at a point between the anchor ( 42 ) and the floating installation ( 20 ), so that when the floating installation ( 20 ) is at a the first depth the mooring weight ( 43 ) will rest on the seafloor ( 4 ), and when the floating installation ( 20 ) is at a the second shallower depth, the mooring weight ( 43 ) will be suspended above the seafloor ( 4 ); and

wherein part of the interior surface of the aperture ( 22 ) facing the tower ( 14 ) and/or part of an exterior surface of the tower ( 14 ) facing the interior surface of the aperture ( 22 ) is covered with a protective layer ( 16 ) selected from the group consisting of: cellulose friction paper and graphite friction plates.