A high-aspect-ratio twin-hull vessel (acronymed HARTH) refers to a certain design of catamaran vessels with small waterplane area. These vessels are built and used by the Islamic Revolutionary Guard Corps (IRGC) of Iran. Such design is considered relatively rare in military usage.
The design of vessels is being described as looking "almost like a pond skater" because of the superstructure sitting above tall legs. Due to the large length of the hulls in the water (also known as pontoons) and also the high height of the deck above the surface, it has a high length-to-width ratio (and is thus called high-aspect-ratio). This design enables small speedboats to move under the ship, which can technically make certain tactical scenarios possible. In comparison to a conventional catamaran, HARTH design allows decreasing the drag forces of the hull and thus breaking the seawater during sailing more easily, as well as more transverse stability in harsh sea states as a result of low heave, pitch and roll motion.
The structure is made of aluminum.