Marco,
Sure it could be done that way. Is it worth doing.....? Well maybe it is as you can't trust it!!
Instead of waiting for Noaa, this could be corrected manually. The tools are all over this forum in different threads about chart conversion, and in the
opencpn.org wiki.
The
work flow would be something like this: Extract the picture from the .kap with "imgkap" or "bsb2tif", rotate the picture with "convert"(for example) and then make a new kap using the original header info, a bit reshuffled. The final size could be cut down quite a bit by cropping the picture and doing a new geo-referencing.
Assuming that the original is a proper Mercator chart, the re-worked chart would then quilt seamlessly with other
charts.
Thomas