An ice boat (often spelled as "iceboat") is a boat or purpose-built framework similar in functional design to a sail boat but fitted with skis or runners (skates) and designed to run over ice instead of through (liquid) water. Ice yachting is the sport of sailing and racing iceboats. Sail-able ice is known in the sport as "hard water" versus sailing on liquid or "soft" water. A related sport, land sailing, utilizes a configuration with an iceboat-like fuselage or frame equipped with wheels instead of runners. Iceboats commonly used for racing are usually only for one person, but several classes of two-seat and multiple-seat iceboats are more or less common. On some boats, a "side car" can be fitted to take others along for a ride.