The effects are likely to be particularly pronounced in ships where the propeller slipstream does not play directly on to the rudder. The effects of shallow water on steering in restricted waters such as canals or rivers are usually worse than in the open sea, and are more likely to have dangerous results. The only way to regain control is to reduce speed drastically at once. ◦ When manoeuvring at slow speed or turning at rest in a confined space in shallow water, the expected effects from the rudder and the propellers may not appear. Water cannot flow easily from one side of the ship to the other, so that the sideways force from the propellers may in fact be opposite to what usually occurs. Eddies may build up that counteract the propeller forces and the expected action of the rudder. Stopping the engines to allow the eddies to subside, and then starting again with reduced revolutions, is more likely to be successful