Temporary boat bottom treatment

[Stumpy]

Does anyone know of a treatment, besides bottom paint, that you can use if you are going to have your boat in a salt water slip for around 2-3 weeks? A friend is vacationing at a house with a slip and only uses his boat in fresh water. He would rather not have it painted and doesn't want to have to go through the removal process when he gets it out of the water. Tried looking on line and everything that I can find is permanent.

Thanks

Stumpy