Is scuba diving when the tanks are floating on top of the water if not what type of diving is it when the tanks float on top?

Its not really Scuba diving but its considered scuba diving. Also known as the hookah system. its when you have a gas powered motor pumping fresh air to the person or person's diving below, there can be up to four people diving off of one hookah system. the benefit of this system is that there is no decompression time and you can be underwater pretty much all day if someone fills the gas tank on the engine pumping air. but you are kinda tied down to something so i don't think its true scuba diving.