What is the "Steering Wheel" on a boat called?

Helm

helm ~ the wheel or handle by which a ship is steered
Example: He asked me to take the helm (= steer the ship).
translations
Arabic: مِقْوَد، زمام الأمور
Chinese (Simplified): 舵
Chinese (Traditional): 舵
Czech: kormidlo
Danish: ror
Dutch: roer
Estonian: tüür
Finnish: peräsin, ruori
French: barre
German: das Steuerruder
Greek: πηδάλιο
Hungarian: kormányrúd, -kerék
Icelandic: stÿri
Indonesian: kemudi
Italian: timone
Japanese: 舵
Korean: (배의) 키
Latvian: stūre; stūresrats
Lithuanian: vairas
Norwegian: ror
Polish: ster
Portuguese (Brazil): leme, timão
Portuguese (Portugal): leme
Romanian: cârmă
Russian: руль; штурвал
Slovak: kormidlo
Slovenian: krmilo
Spanish: timón
Swedish: roder, rorkult
Turkish: dümen yekesi

Helm is a verb as well as a noun. To helm is to steer/navigate/captain the ship/boat/yacht, and the helm is the steering wheel and compass and navigational equipment etc.

In the navy we called it the ships wheel. “Man the ships wheel, ya scurvy dog!”