Design of the Enlargement by Bulges

The hull elongation of “Ushio-maru” is illustrated in the next figure. By putting bulges in both side of the hull, this can realize that the improvement of the ship’s stability, the reduction of hull resistance as well as the supplement of wide work deck on the bulge. The theoretical and experimental works both in Hokkaido University and in the National Research Institute of Fisheries Engineering have been done to get the optimum shape of the bulge.

The principal plan for the elongation is the followings.

  1. The length of the ship is to be extended 6.24m (12 frames), The gross tonnage (Japanese) is increased to 179 ton from 128 ton. The complement is 33 persons (crew:15p, instructors & cadets:18p).
  2. Bulges are fitted in both side of the hull in order to improve the ship’s stability and propulsive performance. Bulwarks are also provided at the side top of the bulges.
  3. False decks with 500mm height are provided on the every outer upper deck and bulge top for the better workability and safety at the rough sea.
  4. Bulbous bow is fitted in order to reduce the hull resistance, which maintain more than 11-knots of navigation speed.
  5. Ocean Schilling Rudder is equipped to keep the strong steering force in harbor.
  6. Cruising area is extended to A3 (International).