Here is a stupid question.I just installed Mercs. solid hub kit for an XR drive into my Bravo ones and realized there is no provision for a nut locking ring.Is it me or is it not needed for some reason.Maybe the curved washer has something to do with it?Does the curved washer go with the center of the washer curved towards the prop or away?

Thanks Nordic95

Don't know, but my McGard prop locks use the cupped washers also instead of the locking tab. Mine are stamped to have the middle of the washer with the curve away from the prop, against the nut.

My local marine shop told me first install the spacer, then the cupped washer with the high side toward the nut (convex forward), then flat washer, and nut. This is for P/N 840383A2.
Let me know if this is incorrect, I can't find it in writing anywhere.

I know it's an old thread but it may be helpful to someone... I could have used it today.

That is correct. When you torque down the prop nut, it smashes the curved washer against the spacer, thereby putting tension on the nut itself as it tries to push back out.

Use a nylon lock nut anyway.