There is one other one that just came out that uses a piezo electric transducer and water to make "smoke". They say that you can color the water with food coloring to make colored smoke. They were available out of Europe somewhere. The picture showed more smoke (water vapor) than I would ever need. They operate on the same principle as those cool mist vaporizer/humidifiers. The piezo element vibrates at a very high frequency causing the water to vaporize producing a nice size vapor cloud.

Years ago we had one of those humidifiers when the kids were young and unless you used distilled water, the piezo element would develop a mineral build up on it and quit working. The remedy for that was pouring white vinegar on it untill it dissolved.

My concern would be if you colored the water, would there be a colored residue left on the boat deck.

edit: Ltdoc- you beat me to it. Thats what happens when you have to step away from your desk at work.