You need to call Imtra in Mass. they will tell you what type of chain i not shure if it is metric there price on replacment rope and chain 10 years ago was $650.00
If you smell the bleach you are still below in levels. In water systems you smell bleach the rule is you are low so if you smell it you are in a very safe range. In water systems a state inspector will flunk and fine you.
I have Charter Lakes out of Kent Island MD and they said smaller agents who did not do enough work with them were not renewed. They said have just put 6500 policys with New Hampisure.
The cost of bow rails when searay had them were $15,000. A very good welder can fix that. Several years ago a boat in the yard i am at got it done $900.00 per stanchion.
You can see a crack in your picture that wet spot. It is a heat related crack or dirt was in casting when it was porred. When engine get hot the crack opens up and when cooler it seales back up it happens on home hotwater heaters a lot.
I had a 1971 180 with a 120 and had it for 10 years. On front of engine mount from serray they put a 3x4 peice of wood across front for engine mount. Got rid of it in 1991 stringers went and floor would flex up and down. Check out gas tank for rust on bottom they are 18 gallon.
Cliff the problem you are having is called station wagon efect the exaust is getting sucked in to boat by your aft extencsion. Sea Ray did not offer aft canvis on v drive boats due to that problem they only came on IO boats.