Buoyancy aids ON at all times. A boat need not be off her moorings at the preparatory signal. Any boat recrossing the finish line is automatically disqualified without a protest hearing. The course is shown on a board in the clubhouse, both as a diagram and as a sequence of marks. The marks are placed clockwise round the reservoir, with 1 to the left as you face the water, going round to 9 on the right, with F in front of the clubhouse.
Odd numbers are orange spherical buoys, even numbers are yellow cans.
There's also a pink 'X' roughly in the middle which gets used sometimes. Don't get confused with the rescue boat moorings. Thames Water don't use Island Barn very much, but if pumping is in progress it is particularly important to keep at least 25 yards clear of these areas. There is a chequered buoy moored near the clubhouse, if you go between this and the bank you may hit the inlet pipes, depending on the exact depth of the water and the 'draw' of your boat - in short, don't do it. Consult the sailing instructions for full details.