I do think 3/16 is right but it shouldn't be just any 3/16 needs to be high quality non stretchy stuff. I did mine a couple times this year and it's not to bad once you get the hang of it but it is hard to describe so pictures are good. I just the boat away for the winter but Doug doesn't put some pictures up soon I will see if I can dig out the rudder casting and snap some pics. In Fact maybe I can make it a Tutorial that can be posted for others as well.