My boat is equipped with twin 3116 Caterpillar diesels. It is a 1995 model.

I am hauling it out for bottom paint in two weeks. They will replace all of
the external zincs as part of the paint job. While it's out, I would like
to replace all of the zincs on the engines as well. This is not included in
the paint job, so I would like to do it myself. The problem is that my
manual is very vague about where they all are. It says that I should have 8
zincs per engine and has a picture of 2 of them. I can find those 2. I
still can't locate the other 6 though.

Short of hiring another mechanic to replace them and watching him, (Which
isn't out of the question) what is the best way to find the other zincs and
is there a way to know the sizes of all of them before I go to work so that
I can go buy new ones ahead of time?

Any advice would be greatly appreciated!