This first year, I used 750 feet of 3/32" of hot-dipped Galvanized cable to wind down a submersible slalom course. I will be making some adjustments so it would be fairly easy to swap it out with Stainless if there was significant benefit. One supplier that distributes both says galvanized can last decades in water - but that was generic comment not specific to cable products. If I could expect 5 years that's good enough for me. Its not a cable course. The cable attaches to a winch to pull down a course with individual anchors for each buoy anchored with poly rope. 250 feet of the cable is running through thick walled polyethylene tubing where it has lake-bottom contact so maybe galvanized would be affected by 30 feet of movement in the tubing when winding up and down ?