'Induced drag' is a good search term for learning about tip spillage and end plates.
Here's a false-color model of induced drag:
And this photo gives you an idea of the energy dissipation (in the form of drag) entailed by tip vortices:
Some planes have added winglets to try to limit air from leaking around the foil's tip. They work, but the effect is most beneficial in planes with stall-prone wingtips, or in commercial applications where small inefficiencies can add up to millions in fuel costs. In the low-speed, high-wetted-surface world of recreational displacement sailboats, induced drag off sails & foils mostly vanishes in the noise.