On Prof. Joly's method of avoiding collision at sea

The ingenious method proposed by Prof. Joly for avoiding collision at sea is so simple, both in principle and in practice, so far as can be judged without actual experience, that it may seem superfluous to attempt to introduce still greater simplicity. But this quality is so important in expedients of the kind that an attempt may find excuse. Since the problem of collision is essentially a question of relative position, it is naturally reduced to the lowest terms of simplicity by employing the relative speed of the approaching ship B. By the familiar artifice of superposing the reversed speed of ship A on both ships, A is brought theoretically to rest without altering the conditions of the problem.