Usage patterns
〈人〉が舵を握るfor someone to grip/take control of the helm (often figuratively, to take charge)
The new president took control of the company's direction.
舵が故障するfor the rudder to malfunction/break down
The rudder broke down during the voyage.
Expressions
舵を切るchange course; shift direction 舵を取るsteer a ship; take the helm · manage; take command; take the helm