What happens to hair when it is in salt water?

Answer 1

All they say is that it makes your hair softer.
Salt does several things to the hair being an alkaline substance it helps to open the cuticle, and is used in many hairdressing preparation's usually as a Sulphide leaving the hair susceptible to damage.
if combined with strong sunlight salt can act like a bleaching agent and de-colour hair. Salt is usually found in shampoo to help the liquid feel more creamy and is also a method of making shampoo cheaper because salt will cleanse and can be added as a thickener

Answer 2

Salt water can cause hair to become dry, brittle, and tangled due to its dehydrating effect. The salt can strip the hair of its natural oils, leading to damage and breakage over time. It's important to rinse hair thoroughly with fresh water after exposure to salt water to minimize these effects.