An often misunderstood concept in power boating, is figuring out how to select the correct propeller for a given boat & motor combination. Understanding the "theory" behind this process can take some of the difficulty, and mystery, out of the process.

2 primary factors are involved - available power & hull efficiency

In theory, a 12 pitch propeller will move through the water 12 inches for each complete revolution. That would be true in application if there was no slippage between the prop and the water. Of course that isn't the case, all propellers have slippage, some more than others - due to limitations of design and application.

Your engine could have been fitted with a 9,10,11 or 12 pitch prop. Selection from OMC was very limited back in the day. Which prop is the "right one?"

The FiberGlassics® Wiki is a community project that is open to all registered users of Fiberglassics.  Guests and members can view articles, however "Editors" can create articles and documents to contribute to the project.

The project attempts to classify, describe and document the classic fiberglass boats of the 50's and 60's through the use of articles, links and relevant media.

All content is viewed by the community for accuracy and you are encouraged to contribute by submitting articles via the Contact Us form.  Once your article has been reviewed, it will be published and you can become an "Editor" if you wish to continue contributing.