∴F floating point =G,

∴ The buoyancy of the ship subjected to the Yangtze River water and seawater is equal to the gravity G of the ship, so the buoyancy of the ship remains unchanged;

∵ rho river

According to F float =ρgV row, the volume of river water discharged by the ship is larger than that of sea water, that is, the volume of boiling water will be smaller.

So the answer is: floating conditions; Constant; Get smaller.