The beam of a boat refers to the width of the vessel at its widest point). It is measured from the port to the starboard side of the boat, and it is an important factor in determining the stability of the boat). Generally, the wider the beam, the more stable the boat, but this can come at the expense of secondary stability in the event of a capsize, where more energy is required to right the vessel from its inverted position). The beam of a boat is also important in determining the amount of storage space available on board. The beam of a boat can be measured using a tape measure, by running it from the farthest side of the port to the starboard point that is parallel to it.