Akademik Ioffe is a research vessel, named after the Soviet physicist Abram Fedorovich Ioffe. Built in 1988, the vessel has a displacement of 6,600 tons, and a length of 364 ft (111 m). Akademik Ioffe and Akademik Sergey Vavilov were built as a joint project. Both ships feature a vertical shaft about two meters in diameter, which opens from the main deck into a special room, from which an acoustic receiver or a transmitter can be lowered to below the waterline by means of a winch. The vessels were used for experiments on the long-range propagation of sound in the ocean.