As to how bad the damage is: Port prop has a good size chunk broken off the lower edge of the skeg as well smaller chunks on the corners.. Starboard sked has less damage but it has a slight cupping to the lower third of the skeg. I patched the missing areas with JB Weld and that has held up for a couple of outings. The LUs seem OK no new vibrations or loss of handling. I could live with the fix boating wise but mentally I am not comfortable not fixing it. The boat is coming out soon for the winter ( in Brooklyn NY) so I have the whole off season to get the work done.
With regard to the replacement skegs, I was confident that replacement skegs would be available on-line but I can't seem to find one that specifically fits by motors inline 4, F200XCA.
IN addition, when I last had a skeg replaced on a Merc motor, I bought a TH Marine replacement but the shop said it was low quality aluminum casting and they wouldn't use it.
I liked that shop, the work was excellent but I had a summer home back then close to the welder. If I wanted to use the same welder, I would have to drive 150 miles round trip to drop of the LUs and later on another 150 to pick them up. I may still take that route but if anyone has had good experiences with a shop, that would help my search.
It is also surprising in a way that my searches for skeg repairs returned only a couple of shops and none in my neck of the woods.
I will do a runout test, that is a good idea.