There is a continuing problem with getting sufficient reliable performance data for bilge keel yachts on which to base refinements of my Portsmouth Number equivalent formula for these craft.  So, I have decided to look at the problem from a different angle. Given that the formulae for fin keel boats continue to work well, my current quest is to look at designing an appropriate adjustment that will enable the same formula, in essence, to be used for all keel types.  A significant advantage of this approach is the possibility of extending it to the TCF models described in Articles 2.6 and 2.9.  I will report on progress in due course.