Unalome tattoos are first spiritual symbols. In Buddhism, they are the visual image of reaching enlightnment. The spiral means our struggle with life, while the straight line shows that we have finally found harmony.
A Wave is symbolized as one of the strongest forces on earth. so strength for one. also if you read more into it, its about faith, a wave is you against mother nature, you cannot control it, you just have to put your faith into her.