Question

A portion of ships are replaced each year. why?
​

Answer 1

Answer:

I think because of corrosion the metal looses its orignal property and become weak. Because it stay in for too long

Answer 2

seawater contains very high salt content, due to which the parts of ship, which are in the contact with water, starts to rust.

Thus those parts are changed annually to prevent the ship from Drowning.

THANK YOU

HOPE IT IS USEFUL :D