If the ship's own speed is X and the current speed is Y, then the downstream speed is (x+y) and the upstream speed is (x-y), and the distance from Port A to Port B is S, then the ship has 6(x+y)=S from Port A to Port B, and 8(x-y)=S from Port B to Port A. By solving the equation, we can know that X = 70. Then it takes t=S÷y=6(x+y)÷y=6(7y+y)÷y=48 hours for (1) to drift from port A to port B at the current speed. (2) If the lifebuoy falls into the water and the ship arrives at Port B one hour later, it can be known that the drift distance of the lifebuoy from falling into the water to finding the lifebuoy is S 1=(a+ 1)y, which is equal to the distance that the ship travels downstream for one hour minus the distance from Port B to finding the lifebuoy for one hour, that is, there is an equation S65438. Combining the two equations, we can get a= 1 hour, that is, the lifebuoy falls into the water after the ship sails from port A to port B for 5 hours.