"
I'm like a boat on the water
You're the rays on the waves that calm my mind
Oh, every time
The boat is the singer in this metaphor, where they are now on a journey with destiny. The boat may not have any significant meaning, but the waters may have a deeper thought in the sense that water is always unpredictable and may often be compared to a false person's identity as a soothing fluid until it crashes hard.
The raise on the waves are the way waves rise and fall, just like a person's heart. The rise in waves is similar to the heat and passion of a person, that calms and pushed the 'boat' forward, towards the destiny they desire.