Bravo 3 Stern Drive Props

delhaven

The props on my stern drive are matte finish stainless steel, not polished. They have discolored, looks like rust, but shouldn't be rust because the props are stainless. The boat is on a lift, used in salt water, but the props are hosed off after every use. Anyone else have this problem? Anyone know how to remove the discoloration without removing the props to be cleaned with a buffing wheel?

HydroCanis

I recently replaced my aluminum prop with a painted stainless steel factory type. Once the paint wore off, a little surface rust appeared. Here's my understanding: though it's called "stainless steel", it isn't entirely rust-free, but rust shouldn't penetrate deeply. The types of relatively inexpensive stainless steel that contain enough chromium to never rust at all are not as strong as those with less chromium, so a little surface rust is tolerated in exchange for full strength. After I used it in salt water, I washed it off with Salt Terminator, and no further rust has appeared (while parked somewhere away from salt water). I'm guessing that being on a lift means the prop is in a salt-air environment most of the time, so I wouldn't know what else to do besides applying a little paint or coating every once in a while to seal the metal from salt and oxygen.