In the January 2012 issue, we evaluated the application ease and traction performance of do-it-yourself nonskid options. A few months prior to the report, a Practical Sailor tester applied the tests Best Choice pick, Durabak, to the coachroof of his Chesapeake Bay-based 1978 Union 36; this served as a real-world test of the coating systems application ease and coating longevity. That field test has reached the five-year mark, so we wanted to offer an update on the coatings long-term performance.
We recently launched a new evaluation of marine adhesives and sealants. There is no single caulk that works in all of these cases, so its impossible to declare a single Best Choice adhesive, but we decided to at least put some numbers on paper to guide you in your choices.
When it comes to most mechanical things-like wheel bearings on a car-its miles that wears em out, as my grandfather used to say. And while there are many reasons why 200,000 miles on a modern car is less remarkable than 75,000 miles was in his day, improvements in lubrication rank high on the list. Lubes of old would oxidize to sludge, stop circulating, wash out, fail to suspend dirt, and drop in pH from acid buildup-or all of these.
While using the right winch grease is important, servicing the winch before the grease turns to gum, washes out, or the pawls start to hang up is more important. Makers recommend annual servicing, but racers and full-time cruisers may go one to three years, and weekend sailors might stretch it a bit further. Three years really would be the max, unless you can live with increased wear. If you go any longer, you risk increased wear and even damage. If the pawls hang up and the drum releases, parts can break, and people can get hurt as the handle whips around.
Our boats are molded, heart and soul, from fiberglass resin. And while sailors will argue for hours over the best splice, multi-function display, or anchor, repairs or modification to the actual fiberglass structure are considered a black art. However, working with composite structures is not much more complicated than woodworking; it just requires a new skillset and a different bag of tricks.
Breathing life into an older fiberglass boat always entails more work than was expected, but for a person with the time, skill, and do-it-yourself inclination, it is often worth the extra effort. The DIY approach makes even more sense when the boats structural quality and big-ticket components meet the grade, and the skipper and crew are ready to tackle the cosmetic makeover. These fairing compounds are perfect for structural and cosmetic fiberglass repairs.
Testers evaluated sandability, resistance to sag, cure time, and adhesion using sample fiberglass panels with 3-by-3-inch test swatches. The fairing compounds were applied and cured in temperatures ranging from the low 60s to the mid-80s. Each test was repeated three times, and the results were averaged. The shaping test involved closely timed periods of even sanding using a block sander and new sheets of 80-grit sandpaper. Testers observed each materials tendency to clog the sandpaper, and measured the volume of accumulated dust after four minutes of sanding.
Epoxy fillers can be used to fix surface imperfections or for reshaping appendages like keels and rudders to make them more efficient. The smaller the surface imperfection, the less viscous the fairing compound should be. When filling deeper holes or voids, check the manufacturers recommended thickness per application. It may take two or more coats to achieve the necessary thickness. Applying filler too thickly can cause it to sag or will result in an incomplete cure.
One of the more popular uses for fairing compounds is for shaping underwater appendages like keels and rudders so they are more efficient. Adjusting the NACA (National Advisory Committee for Aeronautics) profile, or airfoil shape, of a fin keel or rudder can create more lift to enhance windward performance. Altering the trailing edge can yield similar improvements.
How much load does a keel bolt or a winch through-bolt put on a hull or a deck? How thick should the laminate be at these bolt holes? How big of a backing plate is needed?