NEW PROP QUESTION

[tsubaki]

I'm gonna throw some $.02 out there.
The ones available are a 15",17",19" & 21".
Well the 15" and 21" are out as far as I'm concerned. The 15" would be for slow and overloaded situations and the 21" would be for haul *** situations on a light boat , so neither apply. The 17" might be a good all around prop or the 19" may work if the boat isn't overloaded.
Need ya'lls input.