For the Winter and Summer races held in the UK, your GPS needs to be configured as follows:
Position Format: British Grid/British National Grid
Map Datum: ORD SRVY GB
Your GPS will report your position with a high degree of accuracy. For simplicity we shorten this to a six digit reference in most instances. Please ensure that you understand the BRITISH GRID system on your paper maps. BRITISH GRID uses a combination of letters and numbers to signify your position.