I wouldn't get worried a lot regarding the fin on The underside, just seal it up so it isn't going to leak. Ironically I welded up a lower unit just two days back. Man strike a rock and punched a hole during the front of his unit, dug the chunks https://shaneuisb08531.blogitright.com/31809833/the-best-side-of-outboard-lower-unit-repair-near-me