In pinnipeds, two types of porpoising have been identified. This type of travel is known as "porpoising". The P6M-1 also had a serious control deficiency due to porpoising under some trim settings. This type of travel is known as porpoising. This configuration, unique to US submarines, was an attempt to reduce the effect of porpoising. Often porpoising, the group chop up the water tremendously. For these species porpoising was not a necessity. Porpoising (seen in cetaceans, penguins, and pinnipeds) may save energy if they are moving fast.