A cargo barge is loaded in a saltwater harbor for a trip up a freshwater river.If the rectangular barge is 3.00m by 20.0m and sits 0.900m deep in the harbor, how deep will it sit in the river?

Question

A cargo barge is loaded in a saltwater harbor for a trip up a freshwater river.If the rectangular barge is 3.00m by 20.0m and sits 0.900m deep in the harbor, how deep will it sit in the river?
answer in meters

drwls · Answer

It must displace more fresh water than it did saltwater to float. The depth below the water line will increase by a factor
(seawater density)/(fresh water density)

That ratio is about 1.025.

Reference: http://en.wikipedia.org/wiki/Seawater