6 foot waves carries more energy than a 3 foot waves

This is true

Explanation:

A 6 foot wave carries more energy than a 3 foot wave because the energy of a wave is dependent on its amplitude. The higher the amplitude, the higher the energy of the wave. Mathematically, the energy of a wave E is directly proportional to the square of its amplitude A. That is, E ∝ A². So, since a 6 foot wave as higher amplitude than a 3 foot wave, it thus has more energy.