Sulfur allergies

So my sister is allergic to sulfur. We found this out one summer when she went swimming in a friends pool that was chlorinated. She breaks out into this rash all over. She has even gotten a small rash from drinking heavily chlorinated water. i heard that cruise ships use chlorinated water in showers/taps, but their pools are salt water. Is this true. It has taken me 6 months to convince my sister to go with me on a cruise and now it looks like she can shower when she's there. Does anyone know if this is legit / or if there is a cruiseline that does not heavily chlorinate water? Has anyone come across this problem?

[Lisa]

The ship produces it's own water - it's desalinated and purer than water that comes out of your tap at home. She should have no problem showering. The pools and hot tubs will be chlorinated (even those with salt water in them.)