1 part coconut rum
2 part pineapple juice,
2 part 7-up
First take a cocktail glass and fill the bottom with grenadine.
In a cocktail shaker, put your rum, pineapple juice, sprite, and ice.
Shake thoroughly for a few seconds to create foam and to mix it together.
Using a bar spoon, pour the mixed cocktail onto the back of the spoon so that it flows down the sides of the cocktail glass. This will create the defined layered effect.
Garnish with a sliced maraschino cherry and an umbrella. You can already hear the crashing waves!