the term “bathtub boat” can refer to several types of watercraft. One type has been designed specifically for the purpose of bathtub navigation, while another type is intended for use on the open water, with a form and design which is meant to evoke a bathtub, and may in fact be a bathtub in some cases. The bathtub boat should not be confused with a bathtub shaped like a boat, which is an entirely different kettle of fish.
In the sense of a boat which is intended to be used in the tub, a bathtub boat is usually designed as a children's toy, although adults have been known to indulge as well. The simplest bathtub boats are simply boat-shaped wooden or plastic blocks which float on the surface of the tub. Some may have movable pieces including tiny people which sit in the boat. More complex models may have features such as sails, along with moving parts.
Powered bathtub boats can use a variety of methods to move around the tub. Some have small engines powered by batteries which turn turbines or a paddle wheel, while others are powered by the controlled deflation of a balloon, or using other innovative techniques. Steering on bathtub boats tends to be nonexistent or very unresponsive, but fortunately they usually survive collisions with the walls and occupants of the tub due to their slow rate of speed.
In some regions of the world, people race bathtub boats at novelty events. Some communities have taken the idea of bathtub boat races to the next level, having competitors compete by racing actual bathtubs or boats closely modeled after bathtubs. The use of a real bathtub in a bathtub race is increasingly rare, with participants instead building watercraft which are designed to perform slightly better than a bathtub. Such competitions may have restrictions on design which are used to encourage people to use designs which resemble real tubs, or to force people to include an actual bathtub somewhere in the design.
The seriousness of bathtub boat racing depends on the community. Many communities use it as a novelty event which is intended primarily to be fun, rather than competitive, with particular praise going to competitors who build boats which manage to navigate the entire course. Others may place a premium on speed, with competitors using more sophisticated boats and competing against prior year champions or meeting up for district races which pit the winners of various area competitions against each other.