Olfactory silence was the trigger phrase. Over on the Nor'sea group there was/is a write up on chlorine dioxide. Here is a copy written by a Dupont
One very serious way of treating a mold/mildew infestation is to saturate the area with chlorine dioxide. This is the horrible gas used in World War I, and it's toxic to every living thing---nothing can survive exposure to it. You can make by mixing sodium chlorite with hydrochloric acid, which you can purchase as muriatic acid in a hardware store. Sodium chlorite is readily available on-line, sold as something called MMS, or Miracle Mineral Supplement.
The first thing you should do would be to remove all the loose materials from the cabin, including any rotted carpeting or other fabrics. Scrub everything with a strong cleansing solution, then rinse out as much as possible. When that's done, you're ready to treat the boat interior with chlorine dioxide. Close all the portlights and hatches securely. Be certain to use protective gloves of thick leather, wear eye protection, and at all times avoid breathing any fumes.
MMS is a 22.4% solution of sodium chlorite, so put 88 ml of it in a measuring device, then add enough distilled water to a container to make 400 ml.
Next you will need to go to a building supply store and purchase some Muriatic acid, which is hydrochloric acid. This is usually around 32%, so you will have to mix up a 6% concentration of this. To do this put 72 ml of the Muriatic acid in a measuring device and add enough distilled water to make a total of 400 ml. You now have 400 ml of 6% HCl.
Place four bowls on the cabin sole, distributed evenly from bow to stern, including the aft cabin if that's the configuration of your boat. Pour 50 ml of the hydrogen chloride into each bowl. The next step is to add 50 ml of sodium chlorite solution to each bowl. You must hold your breath while you do this! And exit the boat interior as quickly as possible, while taking care not to knock over any of the bowls!
Leave the boat interior, close it up tight from outside. It's best to hang a sign on every hatch that reads: "KEEP OUT! POISON GAS!" and lock the companionway hatches if you can. Then leave the boat sealed up for 24 hours. The mixed solutions will give off the gas, and it will not only kill any mold or mildew spores that are on exposed surfaces, it will penetrate into any sponge-like porous wood surfaces, killing spores and every other biological entity that might lurk.
After 24 hours, come back and open all the hatches. Let the boat air out a bit, then open all the portlights while holding your breath until you get back up topsides. Let the boat air out considerably more, then go down into the cabin(s) and remove the materials. (They can be diluted with a gallon or so of fresh water and poured down the drain safely.) Your mold/mildew should be totally obliterated by this. Should the problem recur, you can simply repeat the procedure.
I've used this treatment on a basement apartment that got flooded and had mildew and black mold absolutely everywhere. After I had done the treatment and aired the place out, it was really peculiar to go down in that basement and smell absolutely nothing. All biological processes give off some odors, usually benign. Since everything in the place was dead, there was no scent of anything at all---like olfactory silence.
And a 4 page pdf by Dupont chemical: http://www2.dupont.com/Chlorine_Diox...-Oil-Field.pdf