Originally Posted by Jeff_H
Who ever it was that said that Alcohol can float on the water clearly does not know a thing about alcohol. Alcohol readily mixes with water and adding water immediately extinguishes it. Geez, I hate seeing misinformation on alcohol.
Float was the wrong word to use. The issue was brought up in a case study in BoatUS's book Seaworthy, where an owner had tried to put out an alcohol stove by pouring water on the flames, and the water only diluted the alcohol, but not sufficiently to put it out.
Adding water does not immediately extinguish alcohol fires, if not enough water is used. The water then carried the still burning alcohol down and behind the stove and the hull caught on fire from the burning alcohol. The story is on page 89 of the book. Alcohol will generally still burn until it is below 40% or so by volume. Most alcohols, including ethanol burn with little color to the flames.
Denatured alcohol, which is probably what you use, is mostly ethanol with a bit of methanol mixed into it. The MSDS clearly states the following for extinguishing alcohol fires.
Extinguishing Media: Use water spray, CO2, alcohol-type or universal-type foams, or
dry chemical. Water may be ineffective.
Please note that it clearly states that WATER MAY BE INEFFECTIVE.
That said...non-pressurized stoves, like the Origo, the OP is asking about, are far safer than the older pressurized stoves. However, alcohol does present its share of dangers, as do any flammable liquids on a boat. I do have a few solvents on-board, but they are stored in a water-tight/air-tight container and I don't open the container unless I've brought it up to the cockpit or on deck as a general rule.
One point about the dangers of alcohol stoves had more to do with their unfamilar practices, rather than the dangers of the fuel itself. Lighting a propane or butane stove is something that is probably fairly familiar for most sailors, especially if they have a gas stove or barbeque grill at home. Lighting an alcohol stove is not.