Get in touch with Leigh and Lowton S.C. or Elton S.C.
they both use computerised race management systems and have done so for a long time. They'll both have websites.
Work out start times for classes from PY rating
Produce graphical data of positions at marks of the course per boat per lap.
just remembered - the programme I used to see advertised was written by Colin P McMullen
Our club has been running a homemade system for a couple of years now which has proved itself. However we are now looking at 2 things 1) Expanding the current system. 2) Asking the question are there already approved systems available off the shelf!