The boats entered service in the Polish Navy in 1971–1972, and were assigned to the 3rd Navy Flotilla (along with ORP
Błyskawiczny). The design was overall not successful. First of all, the hulls, made of
hydronalium (
aluminium alloy), had limited durability, especially when sailing at high speed on a rough sea, resulting in cracks. Propulsion was also not optimal, the gas turbine was not fuel efficient limiting range, and there were problems with the gearing of paired engines. The boats were very compact, and were not comfortable for the crews, being cramped, noisy and prone to vibration. Their advantage of very high top speed, was however limited by sea conditions. Due to service problems and wear, project 664 class boats were relatively quickly phased out in the 1980s, after only 9 to 14 years of service. in the
White Eagle Museum in
Skarżysko-Kamienna The only one preserved was ORP
Odważny - in 1990 it was given to the
White Eagle Museum in
Skarżysko-Kamienna. Its original twin 30 mm
AK-230 gun is however replaced with twin 25 mm 2M-3M gun. ==List of boats==