Prop zinc size

[clayzone]

Greetings: I have a power cat build in France. The prop zincs need to be replaced. I don't know the specific model (i.e. F, G, H, etc) that I need. I measured the inside diameter of the zinc and it was 2 1/2 inches. All the info I have found has the shaft size and the OD but not the inside diameter. I have already bought 2 sizes, one was too small and the other was too big. I am having a hard time getting anyone in the industry to measure their prop zinc and tell me what the ID is. An H model is too big. That leaves the F or G to consider. Since zincs are not inexpensive I am trying to get accurate info before ordering again. Please don't tell me to measure the shaft size, etc. I am not at my boat and can't get that info. I just need a zinc that will fit over the nut and 2 1/2 inch will do that. This does not seem to be rocket science to me. The base of the zinc is a circle so measure from inside edge of one side of the circle to the other. So I don't know why I am having so much trouble getting the info. Does anyone know which zinc has a 2 1/2 inch inside diameter?

[S/V Alchemy]

You are being somewhat unclear. Do you mean by "inside diameter" the rim that fits on the inside of the prop hub end, and attaches to the hub by three or more hex bolts (Allens)?

You need to determine the make of your prop, which will give you the size. F, G and H are not standard names for prop zincs with which I'm familiar.

Here's an example for the VariProp, for instance:

DF-107 Vari-Prop Propeller Zinc Anode $15

I would also suggest you root around at Martyr Anodes website, starting here:
Martyr Anodes ? Zinc, Aluminum, Magnesium Anodes for Pleasurecraft and Commercial Craft

I can't imagine your props are so unusual that you can't find the right anode.

[clayzone]

Inside diameter of the bottom of the zinc. That is how big it needs to be in order to fit over the nut.