Research Note

The Copper Plating Question

By mid-nineteenth century many, perhaps most, U.S ships were sheathed with plates made from a composition called "Muntz Metal" which was 60% copper and 40% zinc. Muntz Metal was thought to be slightly ablative, that is, its surface wore off and took any attached marine growth with it. We have always presumed that it was lighter in color than pure copper, probably tending toward brass color.

Copper bottoms appeared in a variety of colors. Freshly applied copper sheathing was, of course, rich copper color. Exposed to air, as in drydock, it gradually turned brownish. If the vessel was in the water, but had not moved for a while, all of the copper rather rapidly turned green. If the vessel had been idle and recently had gotten underway, the waterline area was pinkish, gradually turning to green toward the turn of the bilge. If the vessel had been underway for a considerable time, all of the sheathing was pinkish. The pink color was due to the considerable scouring action of water moving over the plates. Our model preference would be to use real copper plates somewhat brownish, and then apply translucent washes of pink and green stain to make the edges of the plates visually pop.
{Dana Wegner}

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