Waves out of sugar are easy and really cool looking too! And ocean rocks... OMG! You're gonna love this stuff, I promise. Really.
Get yourself some Aluminum foil and crumple it up into a ball, then un-crumple it and set it in a pan with a bit of a lip. Pour your hot sugar syrup into it, colored blue (of course). As that cools somewhat, also add a touch of green-colored sugar syrup, and twirl the two together with a toothpick or bamboo skewer. Once it cools to room temp, release from the foil and it will look exactly like choppy ocean water. As for white caps breaking the surface of that water, maybe Royal Icing would be useful for that?
For the rocks, cook sugar syrup to 320-degrees, then shock the pan in cool water to arrest the cooking process and allow to cool down to about 300-degrees (F). Then add a large dollop of Royal Icing to the hot sugar, stirring quickly with a heat-proof spatula. The mixture will cause the Royal Icing to explode (and cook too) and it looks exactly like sponge or coral. You can airbrush it at that point to add gradient coloring.
Of course, these applications are for cast sugar, not pulled, so you do not need tartaric acid. Just:
100% sugar
50% water
20% (clear) Corn Syrup
By weight, not volume.
Wash the sides of the pot and cook to 320-degrees.