I was looking for a storage solution for my two touring kayaks when a friend told me about the Field & Stream holders available at Dick's Sporting Goods. They are the "J" type holders designed to be screwed into your wall studs with long screws included in the box. Each set comes with two holders and 8 mounting screws.
Installation of 4 holders took about 30 minutes. The holders are cushioned with foam and the exposed portion of the holders where they mount to the wall have a protective coating, similar to spray-in bed liner for trucks, which should be a good way to prevent rust. They are very strong and seem to be a very well made product.