On the Job

How to Prevent and Get Rid of Mold and Mildew

1 December 2020By Capt. Mx

Written by

Capt. Mx

Still pushing water, having enjoyed and excelled aboard square riggers, Whitbread Maxis, the world cup circuit when there were only 7 boats, America’s Cuppers, 12M, modern classics, real classics, salvage, racing, passage, refits, builds and more, for 38 years, 54 Atlantic crossings, 48 world championships, and a few stories more. I enjoy the serenity and clarity that a life between the blues offers, washed by wind and waves, where all that remains is the simple truth of all things, questions for all things technical, and acceptance of all things magic. 

We all strive for clean, pristine decks and lockers, but we have to be on the lookout for M&M (mold and mildew). This usually refers to a dark stain that tends to grow, usually from lack of attention.

It’s caused mostly by moisture — not so much the kind you get from a wave breaking over the boat, but from condensation in unventilated areas, tiny leaks in a freshwater system, accumulated rain, water from a hose, or from a myriad of other subtle, silent accumulations of moisture (on deck, in lockers, on tool bags and harnesses, sails, awnings, and more).

It is anathema to a properly managed deck and that means you are the culprit should it be found. On the bright side, this bacterial monster is easy enough to avoid, but it does get challenging to remove at times, so prevention is essential.

In the nooks and crannies of lockers and kit you store, wipe down with ammonia (Windex) or a solution of chlorine and water in a spray bottle. Chlorine, unless fully rinsed off, continues to degrade material, and once rinsed off, if not dried completely, is subject to M&M.

So, we return to my favorite save-all: a mix of vinegar and water. Vinegar doesn’t degrade materials like chlorine, is natural, and works well if applied correctly. A mixture of 3:1 should work. Take a clean, dry rag, spray the interiors, your tools, equipment, and wipe it all down after letting it sit for a minute. Let the equipment sit on deck in the sun and the air with the locker lids open to ventilate on a regular basis, check for leaks, water entry, and you’re good to go.

If you get the nasty M&M on your teak deck, you’re in another mess entirely. Many would just say get the oxalic acid and a bucket of water and go for it. But always remember, whatever you put on deck ends up in the big blue sea. Given the condition of the world we live in, it’s our duty to assure a gentler impact at all times — and oxalic acid is so corrosive that you shouldn’t even walk on it barefoot. It blanches the decks unnaturally, removing all-natural oils, and often if you scrub too hard, you could end up gouging out between the grains, leaving horrible grooves that need sanding. If your overzealousness achieved this feat, even with vinegar, you should then get wet dry sandpaper and have at it. Perhaps begin with 100 grit, move to 120, 150, and a swipe with 200 should work, and always be aware of the deck around you — and tape off your work area.

Vinegar is the elixir for all things on deck. When using vinegar and water mix, it’s good to wet a towel or sponge and let it sit a while on the blackened area so as to let it take effect — hopefully before it’s allowed to grow into the grooves of the teak. Remember, it is a low-grade natural acid, so let it do its work.

Once you brush the badness away with a little muscle and perhaps a harder-bristled brush, ensuring no remnants are left in the grain, you can see the teak regain her glory as you bask in your own.

This column is taken from the December 2020 issue of Dockwalk.

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