Re: converging ring
It depends on the style of prop. On some props on some rigs if you lose the ring you'll get some venting. The same prop on other rigs, it doesn't seem to matter. Some props don't have them at all, usually the barrel is a bit longer on those.
In theory the ring slows down the water flow over the barrel. This "stacks up" the water so the blade gets a better bite. That's the theory - you decide.
