Drink Soup with a Fork
When you slowly lift open fingers through water, it drains between your fingers. Add speed by flicking your open fingers upward, through water. Water will not drain, but instead; will fly through the air. Speed generates hydrodynamic resistance in the form of a wave. The wave sprays water into the air. The same experiment can be done with a fork. Flick a fork through soup. You will be able to consume a mouthful, if your aim is good. Avoid this experiment in finer restaurants.
Add more power to your stroke and increase your paddling speed. Move to safety by stroking hard and opening your fingers.
Water is cohesive, it sticks to itself. Water molecules bond together when a speeding object moves through it. Inter molecular bonding creates hydrodynamic resistance. When a flat hand moves rapidly through water, it generates wave making resistance. A tiny wave is created, which gives power to a stroke. A hand creates a wake, similar to a boat, as it moves through water. When the paddler opens his fingers, he creates a larger paddle. The stroke will pull more water in a larger wave. The surfer will experience more acceleration. He must adjust his stroke timing and condition his muscles, as more strength is required.
SurferToday offers some good paddling pointers.