Mailport: Marine plywood, fuel additives, through bolt options, winch handle holders

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DIFFERENTIATING FIRS

I enjoyed your destructive wood testing and your patience in waiting eight years to report comprehensive results (see PS December 2023, “Wood Rot Prevention Eight Years Later”). It is useful to note that the phrase “fir” is used rather indiscriminately and is worth a little refinement. Douglas fir is a naturally rot resistant species but is difficult to find. It is found untreated on older boats often in pretty good shape. I have dug up 25-year-old treated wood foundations made of Douglas-fir (labeled DF) and was very pleasantly surprised at the condition of the wood. Hem-fir (Hem, Hem-fir, H-F) is a generic label for a range of trees, nominally hemlock or fir. It is the most common kind of “fir” available (at least in the upper Midwest). Treated or not, it is terrible at resisting moisture and rot. Ponderosa pine (PP) is also commonly used in treated lumber and is a modest performer. Southern yellow pine (SYP) is also a great rot resistant species and is found in premium treated lumber. You may also find treated spruce, pine, or fir lumber (S-P-F) which is also a terrible performer. When buying “treated” lumber it is important to read the grade stamp for species as well as the intended use designation—above ground or in ground. The USDA Forest Products Lab in Madison, Wisconsin is a great source and their scientists are remarkable approachable about anything woody.

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Darrell Nicholson
Darrell Nicholson is Director of Belvoir Media Group's marine division and the editor of Practical Sailor. A lifelong thalassophile, he grew up sailing everything from El Toro dinghies to classic Morgans on Miami's Biscayne Bay. In the early 90s, he left a newspaper job to sail an old gaff-rigged ketch across the Pacific and has been writing about boats and the sea ever since. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida.