Ruth is a marine surveyor and degree qualified marine engineer with a particular interest in naval architecture and aero-hydrodynamics. She started sailing dinghies at school - and in later years raced Lasers and RS200s before moving on to yachts. When not sailing she can often be found paragliding on ridge sites in Wessex and along the Dorset coast.

William is a software engineer with a maths / computer science degree and 20 years experience - building embedded military communications software and commercial database systems. As well as VPRS, he has also developed race planning software - which uses logged polar data together with wind and tide conditions and available sail plans - to calculate optimum points of sail for fast passage making. Actually more at home on a board than on a yacht, he has a good appreciation of the dynamics of sailing.

We now own a Hustler 35 which we occasionally race short-handed with the Poole Yacht Racing Association (PYRA), mostly on the longer passages, and as a result we have experienced some of the frustrations and problems with the rating systems used by clubs in the harbour.

Encouraged by some of our racing friends at Parkstone Yacht Club and building on an earlier research project, we designed a completely new rating system. The system uses a Velocity Prediction Programme (VPP) and works with a restricted set of input measurements - similar to those used for IRC and PHHS. It is therefore known as VPRS (Velocity Prediction Rating System) and is purely dependent on measurement.