greetings luis
i replaced the bobstay fitting on my westsail 28 about 8 years ago. yours looks similar, if not the same. i replaced mine because i found cracking in several other structural stainless steel parts, so i replaced just about all of it for piece of mind.
i suggest you remove the bobstay wire at the clevis pin and then clean the bobstay fitting as best as you can to remove as much staining as possible without abrasives. then examine the visible part closely with a magnifying glass looking for cracks, especially around the top hole. or, use a digital camera. set it to focus close-up and in high resolution mode. then zoom the resulting picture up as large as you can. i did this on most parts on the boat and found lots of cracks.
if there is a lot of stain weeping from the joint where the fitting is bedded in the hull, this could be a sign of invisible crevice corrosion.
there is nothing visible on the surface inside the chain locker except a bulge where the flanges of the fitting is glassed in.
to provide access, i removed my chain locker bulkhead. i then chopped away at the fiberglass bulge with a chisel and hammer until the fitting came out.
i replaced the fitting with duplex grade 2205 stainless steel. (one step up from 316 grade on the corrosion scale). this was expensive stuff !! i chose this grade because the fitting is on the waterline and subject to high tensile stress from the bobstay as well as the risk of crevice corrosion where it is bedded in the hull. i took particular care with cleaning and sealing the joint between the hull and the fitting.
i rebedded the flanges in fiberglass according to the schedule in the construction manual.
boating is fun!
james