A vessel comprising: a hull; and a stern of the hull that is configured such that a hull bottom that is formed nearly level is extended backward, wherein a rudderpost is installed on the stern, and wherein the stern includes: a first hull bottom portion (21;61) that is formed with the hull bottom located at a centerline of the hull in a width direction and is inclined upward in a backward direction at a first angle (Θ) with respect to a line parallel to the design draft, and a second hull bottom portion (31;71) that has a planar shape connected to the first hull bottom portion (21;61) at an inflection position (23;63) and is inclined upward in the backward direction at a second angle (Θ 1) with respect to a line parallel to the design draft, wherein the second angle (Θ 1) is set to be smaller than the first angle (Θ) and is set within a range larger than 0 degree and equal to or smaller than 20 degrees with respect to a line parallel to the design draft, wherein the inflection position (23;63) is located between the rudderpost and a stern end at a position set forward in advance from the stern end by a distance so as to generate a change of a flow field accompanying a change of a current speed, by which, when the vessel is navigating, a water current flowing along the stern flows backward along the first hull bottom portion (21;61) and then flows to the second hull bottom portion (31;71), by which the hull surface pressure is increased and therefore the stern is pushed up by the hull surface pressure, and wherein the first hull bottom portion (21;61) is disposed to cross the design draft and the second hull bottom portion (31;71) is disposed above the design draft. a hull; and a stern of the hull that is configured such that a hull bottom that is formed nearly level is extended backward, wherein a rudderpost is installed on the stern, and wherein the stern includes: a first hull bottom portion (21;61) that is formed with the hull bottom located at a centerline of the hull in a width direction and is inclined upward in a backward direction at a first angle (Θ) with respect to a line parallel to the design draft, and a second hull bottom portion (31;71) that has a planar shape connected to the first hull bottom portion (21;61) at an inflection position (23;63) and is inclined upward in the backward direction at a second angle (Θ 1) with respect to a line parallel to the design draft, wherein the second angle (Θ 1) is set to be smaller than the first angle (Θ) and is set within a range larger than 0 degree and equal to or smaller than 20 degrees with respect to a line parallel to the design draft, wherein the inflection position (23;63) is located between the rudderpost and a stern end at a position set forward in advance from the stern end by a distance so as to generate a change of a flow field accompanying a change of a current speed, by which, when the vessel is navigating, a water current flowing along the stern flows backward along the first hull bottom portion (21;61) and then flows to the second hull bottom portion (31;71), by which the hull surface pressure is increased and therefore the stern is pushed up by the hull surface pressure, and wherein the first hull bottom portion (21;61) is disposed to cross the design draft and the second hull bottom portion (31;71) is disposed above the design draft. a first hull bottom portion (21;61) that is formed with the hull bottom located at a centerline of the hull in a width direction and is inclined upward in a backward direction at a first angle (Θ) with respect to a line parallel to the design draft, and a second hull bottom portion (31;71) that has a planar shape connected to the first hull bottom portion (21;61) at an inflection position (23;63) and is inclined upward in the backward direction at a second angle (Θ 1) with respect to a line parallel to the design draft, wherein the second angle (Θ 1) is set to be smaller than the first angle (Θ) and is set within a range larger than 0 degree and equal to or smaller than 20 degrees with respect to a line parallel to the design draft, wherein the inflection position (23;63) is located between the rudderpost and a stern end at a position set forward in advance from the stern end by a distance so as to generate a change of a flow field accompanying a change of a current speed, by which, when the vessel is navigating, a water current flowing along the stern flows backward along the first hull bottom portion (21;61) and then flows to the second hull bottom portion (31;71), by which the hull surface pressure is increased and therefore the stern is pushed up by the hull surface pressure, and wherein the first hull bottom portion (21;61) is disposed to cross the design draft and the second hull bottom portion (31;71) is disposed above the design draft.