For mobile augmented or virtual reality applications with limited processing power, representing realistic water geometry is a challenge. Many existing solutions are simulations that can only run at interactive rates on desktop computers. This paper presents a lightweight approximative approach to water representation achieved through mesh LOD via clip-mapping, lightweight Gerstner wave calculations, and approximative texture-based effects for boat-geometry interaction. The foundational method is extensible to many applications modeling water geometry, or even landscapes, at a low performance cost.