Target angle submarine observer estimating target angle pictures himself on the target ship looking back at the submarine. Relative bearing of the submarine is the clockwise angle in degrees from the heading of the target ship to a straight line drawn from the target ship to the submarine. When target angle is 0° (or 360° ) the target ship is coming directly toward the submarine. Target angles between 0° and 90° indicate the target ship is moving toward and to the right of the submarine. Target angles between 90° and 180° indicate the target ship is moving to the right and away
Type 90 Kyū-maru to the left of the main gun. The profile of the Type 90 is similar to the German Leopard 2A4 and it uses modular ceramic and steel composite armor, common in contemporary tank designs. The adoption of modular composite armor design facilitates the upgrading and exchange of the armor, and its frontal turret armor is rated at 380mm of effective thickness against kinetic energy penetrators, while the upper frontal hull armor is rated at 320mm of effective thickness against kinetic penetrators. The Type 90 is smaller than most main battle tanks with a height of , a width of ,