Go to the link, Reply #33 and on, have photos. You can see in the port locker the grunge left by the old hose, exhaust gas leak stains, never any water. There really is nothing a light will help you to analyze, the ONLY reasonable criteria for replacement is age, and not use. My boat was built in 1986 and I did this work in 2012. Do the math...
Actually the replacement was well overdue by maybe five years!Don't over analyze this, just do it.
Good luck.
New exhaust hose installed on my '88 today.... exhaust hose FLIX - Page 3
New exhaust hose installed on my '88 today.... exhaust hose FLIX - Page 3
c34.org