Stainless Steel is pretty bullet proof...except for "Crevice Corrosion". Put SS in an environment where oxygen is excluded..like an airtight joint between two SS components or maybe even a porous SS weld joint...and you "can" get crevice corrosion.
The other alternative is..the unit is Chrome Plated Steel or Chrome Plated brass that has gone "punky"... and is not stainless at all. If you mix SS and brass, you can get accelerated corrosion in the brass. Sometimes a magnet can tell..but not always. Some SS is magnetic.
Avatar: RELIANCE (1903) The Largest single masted sailing yacht ever built (Until 2004)...with over 16,000 square feet of sail. Successful Americas Cup Defender.
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1986 Minx. SBC 350/260hp, Alpha I. Red, Honey.