These should be an major improvement since they don't have the high levels of stress that expansion bolts have. No one knows how long stainless steel glue-ins will last. We wanted a bolt that could be trusted for over 30 years in this environment. We still couldn't ignore the more common corrosion mechanisms such as oxidation, galvanic and chemical corrosion. Galvanic corrosion occurs when two dissimilar metals are in contact in the presence of an electrolyte.
Salt water is an excellent electrolyte.
Multi-piece bolts always have some potential for galvanic corrosion since it's almost impossible for the shaft, sleeves, nut and hanger to be perfectly matched. Chemical corrosion could take place if there is some unusual compound present in the rock that could attack the bolt. It's common for limestone to have a wide variety of compounds embedded in it. There were several possible materials we could use, but we needed a marriage of material, costs and supplier. Titanium was our first choice and after being turned away by several climbing equipment manufacturers we hooked up with Ushba Mountaineering.