I would like to remove the old hatch which leaks and install a new trapezoidal hatch with smoked Perspex.
The new ones are all significantly larger than the existing opening and I don't want to start hacking into the foredeck (I suspect the perimeter of the opening is structural).

One thought I had was to somehow (?) create some sort of base on the existing deck which would be outside existing opening. Then mount the hatch on that. I know looking from the top it would look a bit weird but does anyone have any suggestions. Boat is a Northshore 27.