Paul,
I have a pattern for a yoke which will accommodate a 13" diesel bell which I made many years ago. If you PM me your email address, I will email you photos and dimensions, but it is probably too small. I do not have the desire or time to make one, but if this would work, I would loan it to you to get cast.
The yoke for #11 is similar in size.
The Cattail Foundry may have the pattern or even what you want in stock. Again, if you PM me, I will give you their phone number and explain a few things about how they do things. It is an interesting place.
Bernie
