Nautilus wore Measure 9 throughout her career...this means, in basic English:
Vertical Surfaces:
Paint entire submarine above the waterline black, formula 82. The painting shall be carried over all parts which are visible for the air including the numbers, capstan and running light boards and bridge rails. The radio insulators shall be dark. The shall be no boot topping. The underbody shall be painted with the current issues of bottom antifouling paints.
Horizontal Surfaces:
All horizontal surfaces except wood decks shall be painted Dark Gray 5-D. The systems differ only in the painting of the vertical surfaces. In case of doubt, as on sloping surfaces, use Dark Gray 5-D.
Notes:
The camouflage painting need not be exact or carried into corners. Small gear, wires, rigging, and areas permanently in shadow, as under boats, etc., need not be painted with the camouflage colors. There is no objection to exact or careful painting which may be desired for the sake of good appearance at close range.
All bright or shiny objects, no matter how insignificant, shall be painted, covered, or removed.
Glass windows shall be covered or removed, especially during the day in sunny weather, and at night when anticipating searchlight discovery. Insofar as conditions permit, similar precautions shall be taken on airport lenses.
This is taken directly from the Ships-2 Manual, March 1943 Revision.
Best Regards,
Jeff Herne