Iam in the process of repowering my catalina 30 ,81 model from a old universal 5411.I realize that I will have to reprop also. In order to do the calculations and compare the various makes of props and 2 vs. 3 blade I am wandering if any one out there can tell me what the largest diameter is acceptable for my boat, leaving the proper 1- to 1 1/2 in. clearance from the hull. Many thanks for your helpjd