I believe that was a feature that rotated over the side of the ship and unrolled a canvass "carpet" which was used for recovery of their Arado. The canvass provided a smoother sea surface for the plane to taxi into, and then be recovered by the crane. Allegedly, Langsdorff "deep-sixed" the device as being unnecessary.

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..the funnel. It is a "beam" with oblong holes along its length. It does not appear to support the ships boats in that area.
So what is it and what function does it serve?
Doing the old Airfix 1/600 model. Parts for this "structure" are not included.