Using a large star tip, pipe a blue icing swirl on cupcake, then sprinkle with blue-coloured sugar. Use a toothpick to poke a hole in the thin edge of a lemon wedge candy, and insert a 2-in.-thin biscuit stick. Roll a piece of white taffy candy flat between parchment paper, and cut into a triangle sail. Using food colouring pens, draw lines on sail and use a dab of icing to affix to biscuit stick. Place boat on cupcake.