Anyone familiar with driving a power boat with a planing hull knows that there is that speed just before the boat gets up on a plane, where one is making a tremendous wake off their stern. If one were to back off the throttle at this point this stern wake will catch up to the boat, lift the stern and the boat will for a period of time ride the energy of its own stern wake.
With enough experience, One can time this and actually use the stern wake to more easily get up on a plane with less effort/ using less gas.
I do the same thing when paddling my surfboard, but I obviously cannot get up on a plane paddling. If I paddle with 80% of possible effort, then I push out a bow wake, and my stern wake never catches up to me, If I paddle 85% then back off to 60%, i can feel my stern wake lift the tail of my board, then I can ride my own stern wake, and I can use 20% less overall effort to move the same speed through the water.
Depending on how much wind chop exists, i can cultivate the stern wake, and at times stop paddling and simply ride the energy of my own displacement when riding my longer surfboards, though shorter boards can still do this but to much lesser a degree. Using one's own momentum, and the buoyancy of the board and the sternwake, i can frequently catch waves without paddling at all, and few who witness this will ever consider getttin in my way, and generally scramble to get the F out of it, and away from me in general which is a good things, as crowds suck.