The statement that is correct about the motorboats based on the information provided is:
All five motorboats have the same mass, which can be calculated from the graph.
This conclusion is drawn from the fact that the relationship between acceleration (a) and force (F) is described by Newton's second law of motion, \( F = ma \) (where m is mass). Since the graph of acceleration versus force is a straight line with a y-intercept of zero, it indicates a linear relationship where the slope of the line (change in force/change in acceleration) represents the mass of the motorboats. Thus, if all the motorboats produce the same slope on the graph, they must have the same mass, which can indeed be calculated from the slope of the line on the graph.