Evaluate the use of 316 Stainless Steel for spiral rings in marine environments despite its lower yield strength.

316 Stainless Steel is used when maximum corrosion resistance is required due to its Molybdenum content (2-3%), which protects against pitting in chloride environments. However, its yield strength $S_y$ is significantly lower than 17-7PH or carbon steel (approx. $30-40 ksi$ in annealed state, though edgewinding can work-harden it to $100-150 ksi$). When designing with 316, the thrust capacity $P_r$ must be derated by approximately 30-40%. If high strength and corrosion resistance are both required, a precipitation-hardening alloy like 17-7PH is used, but for long-term submersion in seawater, 316 or specialized Super-Austenitics are mandatory despite the load-capacity trade-off.