We describe a recently proposed Maxey--Riley theory for the motion of finite-size (i.e., inertial) particles floating at the ocean surface. Two settings are considered, to wit, one in which the particles are isolated (e.g., representing ocean debris) and another one in which they form networks and elastically interact (e.g., representing rafts of pelagic macroalgae). This is joint work with M.J. Olascoaga and P. Miron