Accordingly, the invention relates to a main steel struc- ture of one panel of a cargo ship hatch cover, meaning that top plate buckling stiffeners and other such structures of a hatch cover panel are excluded from to the scope of the invention. Conventionally, load-carrying hatch covers are comprised of two or three parallel panels aligned trans- verse to the longitudinal axis of the ship, with the excep- tion of the foredeck hatch cover that usually is of a sing- le panel construction. If a hatch cover is comprised of two panels, both panels are side panels. In a multi-panel hatch cover such as a three-panel cover, the panels closer to the sides of the ship are side panels and the panel or panels forming the mid-cover is/are center panels. The present invention is particularly related to the hatch cover side panels, which in detail, when fitted in place, are suppor- ted by three sides to the edges of the hatchway opening, whereby one of the panel sides is parallel to the longitu- dinal axis of the ship and two sides of the panel are transverse thereto. In principle, the hatch cover center panel can be implemented in a conventional manner.

The structure disclosed herein has advantageous dimensions when the panels are designed to allow end-to-end loading of two containers or tiers of containers lengthwise on a sing- le panel (this is very general situation meaning that onto said hatch cover panel may be placed one 40- or 45-feet container, or alternatively, two 20-feet containers are fitted tightly end-to-end over the length of the panel).

The structure of conventional hatch cover side panels is designed to have the support beams running longitudinally aligned at the edges (corner pieces) of the container sides. Such a construction becomes rather heavy. Moreover, its fabrication requires a great amount of surface handling and welding.

It is an object of the present invention to provide a novel type of hatch cover panel, particularly a side panel, capa- ble of overcoming the above-described drawbacks. The panel according to the invention is characterized in that to said panel is attached at least one transverse beam, aligned perpendicular to the longitudinal support beam of the panel, said transverse beam having a length extending from said longitudinal beam toward the other side of the hatch cover panel at least over the width of two adjacent contai- ners, whereby an essentially T-shaped beam structure is formed. Such a beam construction has a plurality of bene- fits over a conventional design, namely: the span of the transverse beam remains shorter than the length of the lon- gitudinal support beams in a conventional design and/or a single transverse support beam can replace a number of the longitudinal support beams of a conventional design. Resul- tingly, the weight of the steel structure will be reduced, the area of structures to be surface treated will become smaller and the amount of welding will be decreased.

In the following, the invention is examined in greater detail with the help of a preferred exemplifying embodiment by making reference to the appended drawings, in which: Figure 1 is an oblique perspective view of a conventional hatch cover side panel with containers loaded thereon as seen from below; Figure 2 is also an oblique perspective view of a hatch cover side panel according to the invention with containers loaded thereon as seen from below; and Figure 3 is a top view of a portion of ship deck and par- ticularly a part of the hatchway opening with the hatch cover side panel according to the invention placed thereon.

Referring to Fig. 1, a conventional hatch cover side panel 1 is shown therein with an essentially rectangular shape.

The dimensions of the panel are usually dictated by those of the containers 3 loaded thereon. Typically, the panel is dimensioned for a length of approx. 13 m in the longitudi- nal direction of the containers and approx. 8-13 m in the transverse direction of the containers. The containers are typically loaded lengthwise on a single panel with 3 to 5 containers placed adjacently and 2 containers end-to-end.

As mentioned above, the hatch cover side panel 1 is sup- ported by the edges of the hatchway opening at its three sides (cf. Fig. 3), whereby one side remains unsupported.

Due to the substantial loading caused by the containers placed thereon, the hatch cover panels must be stiffened with adequate support structures. In a conventional side panel (Fig. 1), this support is arranged so that to the side unsupported by the hatchway opening is attached a beam 2 (later in the text called the longitudinal beam) running in parallel with the length of the containers. Additional-

ly, a number of other parallel beams are attached at equal spacings aligned to run at the edges of the overlying con- tainers. In the arrangement shown in Fig. 1 having four multi-tier stacks of containers placed side-by-side, the number of longitudinal beams 2 is four.

Fig. 2 shows a hatch cover side panel 1 according to the invention comprising again in the above-described manner a longitudinal support beam 2 at its side unsupported by the hatchway opening. Perpendicular to this longitudinal beam is arranged a transverse beam 4 having a length extending from said longitudinal beam toward the other side of the hatch cover side panel at least over the width of two adja- cent containers. The transverse beam 4 is aligned to run essentially along those edges of the containers 3 loaded onto the side panel 1 that remain at the center of the side panel.

The T-shaped support beam structure 2, 4 of the hatch cover panel 1 according to the invention can be implemented in a plurality of different manners. For instance, the trans- verse beam 4 of the T-shaped support beam structure can be extended up to edge of the side panel 1, or alternatively, terminated at a longitudinal beam of a conventional support beam construction, whereby a desired number of longitudinal beams can be used. It is further possible to have one or a greater number of conventional transverse beams adapted be- tween the longitudinal beam 2 of the T-shaped beam struc- ture and the side of the panel 1 unsupported by the edge of the hatchway opening. This means that the longitudinal beam 2 from which the transverse beam is arranged to start need not be the one closest to the side of the panel. As requi- red, a greater number than one T-shaped support structures (comprising a longitudinal and a transverse beam) of the hatch cover panel can be used.

The cross sections of the longitudinal beam 2 and the transverse beam 4 of the T-shaped beam structure can be made open resembling an I-beam or an L-beam, or alterna- tively, they can be made into a box section. Advantageous- ly, the length of the transverse beam 4 is from 2 to 5 times the width of the container 3.

Referring to Fig. 3, the location of the hatch cover side panel 1 according to the invention is elucidated placed on the edge, or side coaming, 6 of the hatchway opening 5 made on the deck 8 of the ship. The longitudinal and transverse beams attached to the underside of the panel 1 are indicat- ed by dashed lines. The foundation pieces 7 for the loca- tion of containers 3 (not shown in Fig. 3) are attached in a conventional manner on the upper surface of the panel. In Fig. 3, only a portion of the hatchway opening 5 (cargo space opening) and only one hatch cover side panel 1 is shown. As described above, the hatchway opening 5 is con- ventionally closed by a hatch cover comprising two side panels and possibly one center panel.

To those versed in the art it is obvious that the invention is not limited to the embodiments described above, but rat- her, can be varied within the scope of the annexed claims.

Obviously, while the invention is particularly intended for use in hatch cover side panels, it may as well be applied to center panels or hatch covers comprising a single panel only.