Why will they die?

Question

If a shipwrecked crew drinks sea water, they will probably die. Why? (I need the scientific answer)

Answer 1

They will be increasing their sodium intake. In an effort to get rid of the extra salt the body will cause urination. That is a loss of water and when they drink salt water to replace it the cycle continues with more sodium in causing more water out. Finally the loss of water causes dehydration and death.