Symbol 3646 from ISO 7000 - Title/Meaning: Propeller 
Function/description: To indicate the maximum propeller output of a marine engine. To indicate on the builders plate of a small craft the maximum allowable power to be fitted to the craft.
Own work using: iso.org/obp/graphics/grs/e35e1251-91aa-4127-a13f-31f5cfa1b5f2 200.png
Vectorization:  Mrmw