Abstract: Arrangement for a boat (1) which has a boom projecting out from a mast (2) and designed to be connected to a sail, especially on a sailing boat (1). The invention enables the boom to be prevented effectively and reliably from swinging around the mast too rapidly on occasions when this is not desired, and thus reduces the risk of personally injury occasioned by the boom. The arrangement (5) is connected via one section (5A) to the boat (1) and is connected via a further section (5B) to the boom (3), the two said sections (5A and 5B respectively) being mutually connected in such a way that the arrangement (5) forcibly urges the boom (3) to swing towards a position substantially transverse to the boat (1).