das Ruder
rudder
A device at the stern of a ship or boat used to steer its direction.
Der Kapitän legte das Ruder hart nach links, um der Kollision zu entgehen.
The captain put the rudder hard to port to avoid the collision.

rudder / oar
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rudder
A device at the stern of a ship or boat used to steer its direction.
Der Kapitän legte das Ruder hart nach links, um der Kollision zu entgehen.
The captain put the rudder hard to port to avoid the collision.

The word 'Ruder' (rudder/oar) has two different technical meanings. In the context of ships and steering, it refers to the steering device at the stern. In the context of rowing boats, it refers to the pole used for propulsion, often used in the plural 'die Ruder' (the oars).
Das große Containerschiff hat ein riesiges Ruder.
The large container ship has a huge rudder.
The idiom 'das Ruder übernehmen' (to take the helm) means to take control or leadership. The image is that of a captain taking hold of the ship's rudder. You can also 'das Ruder in der Hand haben' (have the helm in your hands / be in control) or 'das Ruder abgeben' (give up the helm/control).
Als der Projektleiter krank wurde, musste sein Teamkollege das Ruder übernehmen.
When the project manager got sick, his teammate had to take the helm.
The idiom 'aus dem Ruder laufen' (to get out of hand) means that a situation gets out of control. The image describes a boat that can no longer be steered and goes off course.
Die Party begann friedlich, lief aber später völlig aus dem Ruder.
The party began peacefully but later got completely out of hand.
When referring to the steering rudder of a ship, typical verbs are 'das Ruder legen' (to put the rudder over, to change direction) or 'das Ruder herumreißen' (to wrench the rudder around, to change direction quickly and sharply).
Der Steuermann riss das Ruder herum, um dem Eisberg auszuweichen.
The helmsman wrenched the rudder around to avoid the iceberg.
control / check
'die Kontrolle' and 'das Ruder' can both have to do with leadership and responsibility. 'Kontrolle' directly says that someone controls or has command of something. 'Das Ruder' originally comes from boating, but is often used figuratively. In 'das Ruder übernehmen' (to take the helm), it means to take over leadership. In 'aus dem Ruder laufen' (to get out of hand), it means that something gets out of control. 'Kontrolle' is more general and fits in almost any area. 'Ruder' sounds more figurative and usually appears in fixed expressions.

Nach mehreren Fehlern übernahm die neue Leiterin das Ruder im Team.
After several mistakes, the new manager took the helm in the team.
Trotz der vielen Aufgaben hatte Sofia die Kontrolle über den Zeitplan.
Despite the many tasks, Sofia had control over the schedule.