Which hull type tends to roll unless stabilized properly?

The round bottom hull is designed with a smooth, rounded shape that allows it to glide efficiently through the water. However, one of the notable characteristics of a round bottom hull is its tendency to roll easily in choppy or rough water conditions. This is due to its shape, which can create a less stable platform, particularly when there is lateral movement from waves or wind.

To counteract this tendency to roll, boats with round bottom hulls often require additional stabilization measures, such as keels, bilge keels, or stabilizers, to enhance their stability and recover more effectively from any rolling motion.

In contrast, flat bottom hulls and deep vee hulls typically offer greater stability in calm conditions and better handling in rough water, thereby reducing the likelihood of excessive rolling without the need for additional stabilization. Multi-hulls, such as catamarans, provide a wider base and are designed to have more stability owing to their two (or more) hulls, which helps them resist rolling. Thus, the characteristic rolling of round bottom hulls is primarily why this option is the correct answer.