In a previous post, Ken Juul wrote that lemon juice will take the water stain off the bow. I had my dinghy stored on the fence after our summer trip and gave the lemon juice a try. I saturated a paper towl with lemon juice and wiped in on a patch of stained bottom about a foot square. I put in a little elbow grease too and then wiped it off. I was dissappointed at first because I couldn't see any difference.
So a week later I'm mowing the back yard and I go by the dinghy and see a bright white square patch on the bottom of the dinghy. The lemon juice definately removed the stain over some time. The results were good enough that I'll experiment with cleaning the rest of the dinghy's bottom to get an idea what works best then I'll give it a try on the boat. Looks promising though. I have some rust looking stains up around my bow roller. I think I'll give it a try up there too.
Ray : Great info to know.
If you want instant results on gelcoat/stainless try FSR (fiberglass stain remover) or Bar Keepers Friend. Both have oxalic acid. They work GREAT in a short period of time!!
The lemon juice may be more friendly to PVC/Hypolon on an inflatable. :clap