I don't know the answer to Greg's question, but I thought I would relay some of the conclusions from Powerboat-Report's varnish test in 2001 (they haven't updated it for 2002 yet). Their report was specific to varnish on teak, and they looked for things like gloss retention, color change, and general integrity of the film. When the report came out, the varnish samples had been exposed for about 18 months up in New England, but their conclusions were primarily drawn from observations at the 12 month point.

The first conclusion of value is that every two-coat application failed for all varnishes tested (there were about 20 of them). Several, but not all, three coat applications failed. In all cases, five and seven coat sections remained in tact. The bottom line: put on the full 5-7 coats as the manufacters always recommend.

Where the test may help Greg is in its comparison of Captain's Z-Spar versus Flagship. Captain's starting color was light; Flagship's was medium. Captains, not Flagship, was in the better condition after six months, ranking "best" along with a few other brands. The significant fault noted for Captains was that it was one of six varnishes that darkened enough during the tests that, according to the report, "most users" would call it unacceptable. Flagship was in the group of varnishes considered best at preserving the original color. These results apparently were for the test patches in which the varnish was applied in 5 coats and 7 coat thicknesses.

The best varnish overall, based on their tests, was Interlux's Schooner. It's original color was light, its film integrity after 6 months was ranked best (it and Captain's tied), its gloss retention was ranked good (Interlux Interthane got an excellent, as did some varnishes that did fair to poor on other tests), and it retained its original color after the 12-18 month period. (Note: Schooner, for what its worth, is also Rebecca Wittman's favorite varnish; she's the author of "Brightwork," which is one of the better varnishing books in print).

The one thing Greg might take from the varnish test is that more applications of Captain's, to get to the same UV protection as Flagship, might have the downside of resulting in some significant and undesireable color shift. If the report is accurate, that may be true even with 5 to 7 coats. But it could be an even greater problem with additional coats.

Hope that helps.