I have a Starratt & Jenks 45' sloop with the chainplates fiberglassed into the hull. I dont trust them and will be fabricating and installing external ones. I have found a few pieces of stainless on the boat that had very small rust lines on them, when I tested them with a lever, they snapped very easy on the line. I want to make new ones out of 7075 T6 Aluminum alloy .75" X 2.5" flat bar. The 7075 T6 alloy is not your average aluminum with a yield strength of over 53,000 lbs. Thoughts and input would be greatly helpful.