keep on an even keel
Fig. to remain cool and calm. (Originally nautical.) If Jane can keep on an even keel and not panic, she will be all right. Try to keep on an even keel and not get upset so easily.
keep something on an even keel
Fig. to keep something in a steady and untroubled state. The manager cannot keep the firm on an even keel any longer. When the workers are unhappy, it is difficult to keep the factory on an even keel.