Bow A: Conventional icebreaker bow form with relatively simple V-frame lines
Bow B: Spoon bow form with more convex frame lines than A
Bow C: Bow form with more concave frame lines at the load waterline than A
Stern a: Marina stern with moderate U-frame lines
Stern b: U-frame lines accentuated near the bottom
A comparison of the body plans of these ships is shown in Figure B-2. Model tests were conducted with combinations of the above bows and sterns. These combinations are indicated below by letter: for example, a ship that combines bow A with stern a is given the designation A-a. The combinations of the two propulsion systems are indicated CP for conventional propeller and NP for nozzle propeller, so that ship design A-a is further divided into A-a (CP) and A-a (NP).
1.2 Tank tests
After the basic design work was completed, each ship type was subjected to tank tests, in model ice and open water. The work for these tests was divided among the Shipping Research Institute (SRI) of Ministry of Transport, NKK Corporation (NKK) and Mitsubishi Heavy Industries, Ltd.(MHI). For the model tests, models were prepared for each of the above ship types on a scale of 1:36 and tested in turn by each of the three agencies above. The sizes of the ice model basin of each agency and their types of model ice are summarized in Table B-2.