Re: Catalina 42 ... Why not?
Years ago I was the Measurer for the Catalina 34 International Owners Association. The C34 fleet had a very active one design racing component and a pretty rigorous one design rule which we calculated adjustments for things like roller sails and shoal draft keels. The problem with the PHRF formula is it tends to understate the impacts of things like change in displacement (shoal draft boats have heavier keels). For our 34 footers the difference in time between the two types of keels is more like 20-25 seconds per mile. This translates to a shoal boat being 3-5% “slower” than a normal fin keel. What the measurement doesn’t calculate is the tighter tacking angles of a fin keel. I’d say the fin is tighter by five to seven degrees. From my practical racing experience, I never worried too much about shoal boats as I could easily lift above them so I never had to split tacks, I’d just run them down and lift over them.
So you think this only matters if your are racing? IMHO, it is probably more important as a cruiser. The added weight in the shoal keel becomes a bigger disadvantage as the winds get lighter. So you are turning on the motor sooner and motoring longer. You are not as efficient clawing off of a lee shore, nor are you as efficient if your destination is upwind. My opinion is you have to be a really good and constant trimmer just to keep up with a lazy trimmer on a fin keel boat.
2000 Catalina 34 MkII