In this type, the navigation performance was improved and the design was rationalized based on the operational results of the preceding 1954 planned boats (Kari-class, Kamome-class).

In addition, in the 1954 classes, the bridge and the deck room were separated to reduce the area on the wind pressure side, but there were drawbacks such as the inconvenience of communication inside the ship in stormy weather and the inability to secure sufficient space inside the ship.

Therefore, in this model, the front and rear superstructures are integrated so that it can be easily moved back and forth even in stormy weather.

However, due to these factors, the center of gravity rose and the stability deteriorated, and Umitaka and Otaka were equipped with about 15 tons of fixed ballast.

In addition, since the 1934 boat, corrugated panels have been adopted on the side walls of the superstructure to reduce man-hours and weight.

However, in the 1954 boats, an anti-submarine short torpedo equipped with a guidance device was adopted instead of the 55-type depth charge projector (so-called Y gun) placed on the rear deck.