I set up on the table in the middle of the sailboat cabin. I had a small round standup mirror, a couple terrycloth cotton towels, and a bottle of No Rinse shampoo. My hair is fairly fine and was a bit greasy after a few dats without shampooing.

I began working small palmfulls of the shampoo into my hair. following directions I first made sure the shampoo wetted all my hair. I used about six palmfulls to do that. Then I added a palmfull at a time looking for the lather point. At about 6 more palmfulls I began noticing a thin lather. I added another 3 palmfulls, the lather did not seem to be increasing, so I decided that was enough. I toweled my hair fairly dry.

My hair was no longer greasy but it was not as flyaway as my hair usually gets when it dries after a shampoo. My significant other [who I did not tell about the test]found the result entirely acceptable for running her fingers through and noticed nothing out of the ordinary.

Next time I will find something to measure the amount used more precisely. I think I will also use paper towels.

My verdict: very convenient, no mess, and acceptable results. This would be a nice morale booster at need. You could easily shampoo your hair this way in any confined space or place where you wanted mess at a minimum, without using or about heating water.

Edit: the weight and volume of product used was far less than the combined amount of normal shampoo and water required for even a sink / basin shampoo and rinse.