I just got a new boat, and guess what--the carpet on the cabin liner was heavily blotched with black spots. But They did not relate to any pattern of water leakage, just poor ventilation, so I feared not. I knew they could easily be removed and their return prevented. A good thing to know.
In Chapter 8, Boat Prep I mentioned diluted bleach. This is obvious enough, but remember that bleach can't be used near most fabrics. Additionally, it is not the most effective product at preventing return. And it's nasty to work with.
First, my work-horse anti-mildew formulations. It is cheap, more effective in most cases than anything else, and safe for both you and all materials. Mix up a gallon and dispense it through spray bottles.
No number (this is a repeat). Formula B from Practical Sailor. When asked to review some formulations for the magazine, the chemical engineer in me couldn't resists improving on the available commercial products. The result of reviewing old patents and considering the requirements for cleaning mildewed carpeting was a DIY mixture of borax, washing soda, and TSP (trisodium phosphate--NOT TPS substutute), all available at either the grocery store or the hardware store. This pennies/gallon blend is perfect for cleaning carpet and bilge spaces, and KEEPING mildew from returning. Spray enough to soak, wait 2-10 minutes, scrub for a few seconds, and in the case of fabrics, remove excess with carpet cleaner extractor or shop vacuum. Do Not Rinse, since the residue will prevent the return. Do NOT Increase the concentration; it will not clean better and you will have to rinse. Also very effective for use in a carpet cleaning machine for both wet basements and pet mess (the best thing I have found for cat pee).
No number (this is a repeat). Oxiclean and all sail cleaners containing percarbonate as an oxygen bleach. These are not aggressive, fast stain or mildew removers. They take 4- to 8-hour soak times and seem to need sunshine to help them finish their work (the percarbonate weakens certain chemical bonds and UV finished the job). But they are safe on most fabrics (not wool or silk), nearly always color safe, and are just the thing to remove what Formula B left behind when cleaning white fabrics (not generally needed for anything other than whites).
And now for some new listings:
71. Clorox Pool and Spa Green Algae Eliminator (discontinued?) This is the cheapest way to buy the ingredient we are looking for, benzalonium chloride. A bargain for a 50% solution, this was suggested to me by a Seattle sailor (See Windborne on the sidebar) who was cursed by lichens growing on his deck. This kills them. However, it is also a very effective preventative for both mildew and algae on a variety of surfaces, so long as they are not exposed to frequent rain. Dilute 2 ounces/gallon, spray, and let dry. Also very effective for cleaning lichens from sail covers and canvas. In this case, spray, wait 1-2 weeks, and then scrub; it takes time for the BAC to kill the lichens and moss, and then for the sun to break their grip.
Also good for taking moss off the roof at home. Spray in dry weather, and then just leave the sun and rain to remove the dead bodies.
71a. Wet and Forget. Although 5x more dilute (only 9.9% BAC) , the formula is just as effective, you just don't dilute it as much. Instead of diluting 50:1 to make a 1% solution, dilute 10:1. The result is a bit more expensive, but not excessive if you clean the surface first.
72. Eva-dry-2000 dehumidifier. Discussed in this post, I've been using this dehumidifier for 9 years, and though it lacks the capacity for a home, it is enough for a boat and does not draw so much power as to present a hazard if run unattended (though I do place it on the stove top--seems like the safest place). As described in the post, I added a drain, which is led to the sink. Low humidity in the cabin means no musty mattress or pillow.
73. Keep Things Clean. While hardly a product recommendation, the bottom line is that good sanitation begins with cleanliness, and mildew require food. Wipe all hard surfaces down at least 2x per year. Bilges too. It's not that bad, and when something needs fixed, you'll be thankful.
74. Keep the Bilge Dry. Without a dry bilge, the boat cannot be dry. Likewise all cabin leaks. The most common cause of hatch leaks is dirt on the gasket; wipe them all clean several times each season, and treat with a wax to make them water repellent if the problem persists.
75. Keep a Fan on the Boat. Sometimes things get wet, and it's great to get them dry.
75a. Take Wet Things Home. Yup, lugging is a pain. But they won't dry in the boat and this will teach you not to get them wet. If you have a dodger, leave wet rain gear and towels on deck rather than below. I often do this even if I won't be back for weeks. I've never had anything stolen from the boat. Beaches and dinghies, yes.