BoatWorks: What a Lot of Bilge…

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Okay, so you’ve anti-fouled, varnished, polished, and cleaned. Now that all the obvious spring jobs have been completed, why not turn your attention to your nether regions?

There, that got your attention. I actually mean the boat’s nether regions, as in the bilges.

Clean, sweet bilges contribute more than you think to the quality of life on board. Lower yourself down there and take a deep breath. Are they the major source of that old-boat odor, that combination of diesel, oil, mildew, heads, that casserole that jumped off the stove two years ago during a hard beat? Do they have that fine carpeting of hairs, paint flakes, cotter pins, pencils, paper scraps, screws, and washers? Even if not that gross, most bilges get pretty skanky if you ignore them long enough. This is especially true of the good old boats from the '60s and '70s that many of us run, with their deep hulls and cavernous sumps, and lots of hidden nooks and crannies where boat grunge accumulates. In some boats, there is no gelcoat on the inside of the hull laminate, and the rough surface of the fiberglass traps dirt and absorbs odors. While it won’t completely eliminate boat smell, a good bilge paint will make the boat easier to keep clean.

There’s another reason to protect your bilge with paint. Water standing in a bilge can migrate into the hull laminate. There have been numerous cases of boats coming up with osmotic blistering on the inside, or even with core damage.

I’m a firm advocate in theory of painting bilges during the fall, after the boat’s been hauled, but in practice I’ve twice ended up doing it in the spring, and this year will make the third time. The first time was on a 48-foot wooden boat, and I assure you that that was no picnic. Without ribs, frames, floors, and stringers to worry about, fiberglass boats are much easier to paint.

As with all things to do with painting, the key to success is preparation, preparation, and preparation. In the case of bilges, that usually means getting down and dirty. First thing you have to do is degrease every surface that will be painted. When I come to do this job in the next month, I’ll use industrial-strength Simple Green; it’s biodegradable and nontoxic. Interlux, which makes my preferred paint, Bilgekote, recommends you use its proprietary 202 Fiberglass Solvent or YMA601 Fiberglass Surface Prep. I have no hesitation about using these products on the outside of the hull, but I’m not keen on using them in confined spaces. If you do use these solvents, wear appropriate protection and set up a fan to get air flowing through the boat.

Once you’ve scrubbed the bilges with soap and water (or one of the many proprietary bilge cleaners on the market), rinse with clean water and let dry overnight. Then wipe them down with your chosen degreaser. Apply the degreaser with a rag and then wipe it dry with a second rag (you degrease before sanding so you don’t rub dirt into the surface). The next step is to sand the bilge down to provide a key for the bilge paint. If your bilge has been previously painted, a rotary wire brush mounted on a drill might be the best way to get rid of paint flakes. Otherwise, use a medium-grit—150 or so—sandpaper. Then repeat the two-rag degreasing to clean up the sanding residue.

Back in my wooden-boat days I used an attractive red bilge paint called Danboline; now I’m restricted to a choice between white and gray Bilgekote. This paint spreads out well and dries hard enough to resist a bit of battering with anchors, chains, and other hard things that end up in the bilges. It also resists diesel and oil, and it wipes down easily. The gray is too dark for my taste, and the white is unforgiving to those of us with older boats that seem to shed like dogs. You could mix the two together, but so far I’ve not bothered.

Two coats of Bilgekote, with a sanding with 180-grit and a wipe-down to get rid of the dust in between, should ensure that your bilge looks good and remains easy to clean. A couple of wipe-downs during the season and a good scrub at the end of the year will keep your bilges in tiptop condition. Bilgekote is also excellent for the inside of cockpit and under-sink lockers, which always tend to be dark and musty.

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Posted: April 15, 2008

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