As the tide rushes past Portland Bill it is heading due south but immediately hits the east going tide that has not been influenced by Portland. It therefore very soon starts to bend slightly eastwards running south, south by east, south east by east then south east.

Within a quarter of mile of Portland, with the sea often flat calm because of the power of the flood tide, the water hits the Portland Ledge (you must imagine Portland continues under water for another half mile and the seabed rises from 90' to 30'). Like in a river when it shallows rapidly, the speed of the water speeds up even more. It hits the underwater 'wall' and is deflected upwards to the surface as there is too much water to stay calm over this vast submerged barrier. The first three waves of The Race in full flood can be very dangerous and is, 90 percent of the time, very impressive. The first three waves break the power and slow the water so that it tumbles and becomes confused. It will be traveling at anything up to 5 knots now. This gradually eases and the sea becomes calmer as it travels towards the west Shambles Buoy where, at high water on a spring tide, it will still be at 4 knots. A back eddy builds up (which is why The Shambles is formed) and bends in an anti clockwise direction to travel back along parallel to Portland's east side. This back eddy meets the south going stream at Bill Point, causes further confusion and then also gets deflected southwards to add yet more speed and quantity of water. If there is a cross swell or a south west, south or east wind then further friction is caused making the seas more confused and more unpredictable. With all this going on, you must be very careful about when you decide to fish the Race. It changes all the time; it can be too dangerous for a time (usually high water to one hour after) and then it can suddenly change and become fishable. There are no rules!!

The EBB Race is potentially VERY dangerous but a spring tide (running westwards) 6 to 7 hours after HW Weymouth (at max speed of 7 to even 9 knots) creates a large flat area to the east of the ebb Race which is perfectly fishable. Often the more calm this patch is the worse the actual ebb Race becomes. You cannot miss it. A standing wall of water can be created which will turn you over if you hit it wrong. It's better to stay well to the east of the white water!!

Paul Whittall. Offshore Rebel Charters.