I figured it out it is a snap shackle block I have one, the other one was not with the boat. Trying to find one on eBay.
you can also look on Sailrites web site. under parts I think. they have three wheels the middle one is about what I have, or go really big but the price is kinda steep.You really must tell me how you did this. I have several very old sewing machines that probably have heavy duty parts because they were made around the 1940s/