College Physics with MasteringPhysics 7th Edition by Jerry Wilson,Anthony Buffa,Bo Lou

Exercise 19

Ocean-going ships in port are loaded to the so-called Plimsoll mark , which is a lure indicating the maximum safe loading depth. However, in New Orleans, located at the mouth of the Mississippi River, where the water is brackish (partly salty and partly fresh), ships are loaded until the Plimsoll mark is somewhat below the water line. Why