Lamp shades

[rebelwi@suddenlink.net]

I own the 31 year old Pearson 424, Bobkat.  There are several 12 volt wall mounted lamps using standard screw based bulbs, a fittings common to Pearson built boats.  The lamp shades are spring loaded to clip onto the bulbs.  The ones I have now are so heavy, they emit little light from the bulb and I wish to replace them with a "see through" shade.  Does anyone know of a source of shades for these light fixtures?

Howard