When I was little and every so often money was to tight to pay the electric bill, my mother taught us how to wash clothes in the tub, it was suprizingly easy, a layer of clothes about 1/4 to 1/3rd, less is better, run water to cover the clothes, 1st rinse if they are very dirty don't bother with soap just stomp on the clothes with your bare feet, (as children we loved it) when the water looks dirty drain it out and smoosh the clothes in the high end and stomp on them until most of the water is out, rinse any dirt out of the bottom of the tub and repete, with just enough soap to have a slippery feel between your fingers, (so you can't snap your fingers)
then repete this until the water dosen't look dirty anymore, then rinse until the soap is gone. We would get to play in the tub like this with a radio to dance too, and it didn't seem like work, (your legs don't get tired as fast as your arms)
My grandmother taugh me how to do lots of lanudry in a wringer washer, I really enjoyed the time I spent with her.
To do lots with wash tubs and rub boards can be a chore so it was saved for the hardest to clean items, 3 tubs will do but 5 is lots better to run the clothes through, prewash (1 very dirty none or little soap), one wash with soap, (children can stomp these) and 3 for rinse, and as each becomes dirty it is emptyed and moved to the end of the line to become the cleanest rinse tub, a wringer at each tub would be so cool, but one must often do, I have done it without a wringer by pulling each item out of the water and putting it into a basket to drain, these set in the basket while I work the next batch or change water or whatever, eventually they all get to the end and hung on the line.
It is always more fun to have company to help and to not be rushed about it, and of course this way must be done outdoors in summer. In the shade with icedtea.....