A trip to http://en.wikipedia.org/wiki/Anti-fouling_paint
provides the history of antifouling paint. Here is an excerpt for the grumpy old farts that follow a link
In the days of the clipper ships, sailing vessels suffered severely from the growth of barnacles and weed on the hull, called "fouling." Thin sheets of copper or Muntz metal were nailed onto the hull in an attempt to prevent marine growth. Fouling affected performance (and profitability) in two ways. First, the maximum speed of a ship decreases as its hull becomes fouled with marine growth. Second, fouling hampers a ship's ability to sail upwind.
The inventor of the anti-fouling paint was Captain Ferdinand Gravert, born in 1847 in Glückstadt (Schleswig-Holstein, Germany), who sold his chemical formula in 1913 at Taltal, Chile. Captain Alex Gravert has valuable documentation about this.
One famous example of the traditional use of metal sheathing is the clipper Cutty Sark, which is preserved as a museum ship in dry-dock at Greenwich in England. A modern version of this anti-fouling system, Coppercoat, uses an epoxy resin to permanently attach copper to the hull of the boat, helping to prevent marine growth for ten years or more.[
Regarding the similarity of West Marine PCA Gold and Pettit Ultima SR 40, I found this quote on http://www.sailnet.com/forums/gear-m...sr-60-a-3.html
"From Pratical Sailor in regards to the Pettit SR-40
"the West Marine paints made by Pettit: PCA Gold (re-branded Ultima SR-40)"
Not sure if it's 100% true as Pettit advertises the SR-40 as a dual biocide paint with PTFE (Teflon) and WM only clams Irgarol as the biocide and no PTFE."
I believe if you buy your Pettit SR-40 mail order such as http://www.amazon.com/Pettit-Ultima-.../dp/B000N9T98M
it is only $1.50 more per gallon than West Marine PCA Gold.