Boat design and hull shapes

Tube

Also: tube, side tube, air tube

The tube is the inflatable cylinder running around the boat that provides buoyancy.

Most packrafts have one continuous tube, i.e. only one air chamber. Some models have several chambers, so part of the buoyancy remains if one is damaged. Thicker tubes bring more freeboard and stiffness, thinner ones save weight.

In some boats the tube can be used as storage (TubeBags, ISS, RTC).