The present invention relates to a floating construction, which comprises a water container with at least partially transparent walls, and space for people. Patent application PCT/FI2012/050726 discloses an apparatus for underwater activities, which apparatus comprises a vessel partially or fully filled with water with one or more open openings for entering the vessel, where the lower portion of the vessel together with the open openings for entering the vessel are located below surface level of a body of water. The walls of the vessel are transparent, or the walls comprise sections that are transparent, which allows people to observe activities taking place inside the vessel from outside of the vessel. This application also discloses an embodiment, where the vessel is connected to a floating platform to provide a floating construction. Further, this application also shortly mentions a possibility for providing room for spectators inside the walls of the vessel.

Patent application PCT/FI2012/050942 discloses a floating construction, which comprises a vessel partially or fully filled with water, with transparent walls or with walls comprising transparent section, and with at least one opening allowing the water surrounding the floating construction to enter the vessel. In the floating construction there is a space provided around or partially around the vessel for people to observe activities taking place inside the vessel, which space is enclosed to provide interior observation area. This application also mentions a system for adjusting the draft of the floating construction.

The present invention provides a simple floating construction that can be uti- lized for providing an arena for water and underwater activities, for example.

In the present invention a floating construction comprises a water space within the floating construction, which water space has transparent walls and/or walls containing transparent sections, and at least one open opening allowing water surrounding the floating construction to enter and exit the water space, and the floating construction comprises space next to the water space for spectators observing the activities taking place inside the water space. The floating construction also comprises a draft control system for changing water surface level inside the water space. Advantageously the at least one open opening is opening formed in the bottom surface of the floating construction, and the size and the location of the opening corresponds substantially the area restricted by the walls of the water space. Advantageously the space for spectators comprises auditorium structure at least on opposite sides of the water space, or around the water space.

Advantageously the floating construction of the invention has a cylindrical form, wherein the space for spectators is formed as an auditorium structure surrounding the water space. In a floating construction of the present invention the draft control system advantageously comprises ballast tanks located within the floating construction, and a pumping system for adding and removing water from the ballast tanks.

A floating construction of the present invention may also be equipped with a suitable propulsion system for moving the construction on water. A floating construction of the present invention is advantageously equipped with an anchoring system for securing the construction on water.

The features defining a floating construction according to the invention are presented more precisely in claim 1 . Other advantageous embodiments and features are presented in dependent claims. Exemplifying embodiments of the invention and their advantages are explained in greater detail below in the sense of example and with reference to accompanying drawings, where:

Figure 1 A shows schematically a top view of an embodiment of a floating construction according to the invention, Figure 1 B shows schematically a cross-sectional view of the embodiment of figure 1A,

Figures 2A and 2B show the floating construction of figures 1A and 1 B in different floating positions, and

Figures 3A and 3B show schematically an alternative embodiment of a floating construction of the invention. The embodiment of a floating construction 1 of the invention shown schematically in cross-sectional view in figure 1 comprises a water space 2 formed within the floating construction. The water space 2 is restricted from other areas of the floating construction 1 by vertically extending transparent walls 3, 3'. The lower edges of the transparent walls 3, 3' are connected watertightly around the edges of an opening 4 formed on the bottom of the floating construction 1 so that the area of the opening 4 corresponds the area of the water space 2.

On both sides of the water space 2 and opposite each other are formed seating arrangements 5, 5' for spectators in form of auditoriums, from where the spectators can follow activities taking place in the water space 2.

Under the seating arrangements 5, 5' is formed ballast tanks 6, 6' which are used to control and adjust the draft of the floating construction 1 by adding and/or removing water from the ballast tanks. Since water in the water space 2 has direct contact to water surrounding the floating construction 1 through opening 4, water surface level of the water surrounding the floating construction is in the same level than the water surface level of the water in the water space. Therefore changing the draft of the floating construction 1 , that is the depth in which the floating construction floats in the surrounding water, also directly changes the water surface level inside the water space 2. The ballast tanks 6, 6' are part of the draft control system of the floating construction 1 , which system also comprises suitable pumps and valves for pumping water to the ballast tanks and removing water from the ballast tanks. Further, the draft control system also advantageously comprises suitable means for monitoring the water surface level of the surrounding water with respect to the floating construction. These monitoring means can be infrared or laser based distance measurement sensor, or sensors connected to floats, for example. This way the draft control system can also compensate for the weight of the spectators when keeping the draft of the floating construction at pre-set level. Figures 2A and 2B show the floating construction 1 of figures 1A and 1 B in different floating positions.

In the position of figure 2A, the ballast tanks 6, 6' are empty and the draft of the floating construction 1 is created by the weight of the construction only. In this floating position the draft of the floating construction 1 is at its minimum, and the water surface level at the water space 2 is at its lowest level. This floating position is suitable for moving the floating constructions 1 to different locations over water by towing or by a suitable propulsion system which can be part of the floating construction. Suitable propulsion system may be engines with propellers or water jet propulsion system, for example.

In the position of figure 2B the ballast tanks 6, 6' are filled and the draft of the floating construction is adjusted to be suitable for the use of water and underwater activities taking place within the water space 2 as well as for observation of these activities outside of the water space. In this position the floating con- struction can be either anchored to the bottom of the surrounding body of water with a suitable anchoring system, or fixed to a suitable pier, for example, for securing it in its place on water.

The floating construction of the invention may also be equipped with suitable roof or canopy for providing shade from sun and/or protection from rain at least to the spectators.

In the embodiment of the figures the water space 2 is formed only by vertically extending walls without top surface. The water space may also be provided with suitable top surface, but the top surface must allow air to escape from and enter to the water space, so that the water surface level within the water space can be freely adjusted simultaneously with the draft of the floating construction 1 .

Figures 3A and 3B show schematically an alternative embodiment of a floating construction of the invention, where figure 3A is a top view and figure 3B is a cross-sectional view of the embodiment. As can be seen from figure 3B, this embodiment substantially corresponds to the embodiment of figure 1 B, but the floating construction is formed in cylindrical form, as can be seen from figure 3A.

In the embodiment of figures 3A and 3B the water space in located in the center of the floating construction, and the space for spectators is formed as an auditorium surrounding the water space.

The specific exemplifying embodiments of the invention shown in figures and discussed above should not be construed as limiting. A person skilled in the art can amend and modify the exemplary floating construction described above in many evident ways within scope of the attached claims. Thus the invention is not limited merely to the embodiments described above.