Fungus Is Not Your Boat’s Best Friend

by Dick Werner, ACBS Director
 

There are good and bad funguses. This article is about the fungus that attacks our beautiful wood boats and can leave us with that horrible condition we all dread – Dry Rot. I don’t think I need to describe what dry rot is because, unfortunately, most of us have probably experienced it at a time or two. How does this enemy of ours fit into boating safety?
 

Well, this microorganism is capable of sinking our boats if not caught in time. We are out enjoying a beautiful day on the water when suddenly we develop a leak that results in water coming in faster than our bilge pump can handle. It is bad enough if we hit something and drive a hole through a bottom plank, but dry rot is a sneaker and will often involve more than one plank. These little sneaker organisms are capable of destroying the cellular structure of our wood underneath the bilge paint. Everything looks good until we hit some rough water and the formerly strong wood structure falls apart. What starts out as a small hole quickly becomes a big opening.
 

Fungus does well in a moist, dark, and still-air environment. When is it that we offer this conducive, potential dry rot environment to our boats? Generally it is during the time of winter storage. Most of us do all the right things to properly winterize our engines, but what about the wood hull? Of course we drain the bilge of water and we may even clean it. But so often we store our boats with a cover that fits nice and tight to keep the boat clean and then put it in a fairly warm garage. We have now invited the fungus spores to set up housekeeping in a perfect growing environment. These fungal organisms are not something we go looking for. They are opportunists looking for a place that will allow them to thrive.
 

It would be best not to put a cover on the boat, but if you must, then have it ventilated so air can enter easily. Open enough hatches so air can get into the bilge and any enclosed compartments. If you have an engine box, put a couple of blocks under it so air can enter easily. Remove several floorboards in different locations so air can enter and move around. For cruisers, a low velocity fan in the engine room and/or bilge is a very good idea.
 

You might be concerned about the boat getting too dry. You can safely raise the humidity by setting several open buckets of water around and under the boat without getting the bilge too moist.
Even though you have done all of the above, it is still a good idea at some point during winter storage to inspect the hull, primarily the bottom for any soft spots. If you find any, carefully dig out all of the soft wood and saturate it with Smith’s penetrating epoxy. If it is just starting and you still have plenty of good thick wood left, you probably will be okay. If these micro-enemies of our boats have consumed most of the wood thickness, then you have only one choice, and you know what that is.
 

It is better to catch it and correct it while the boat is laid up for winter rather than when you are sinking somewhere out in the middle of a lake or river. Of course, prevention is the best policy - provide good ventilation.