• RYA has a 2013 review that concludes “You should fit a prop guard only once you have made a full assessment of the impact it will have on your vessel and the operation for which you intend to use it.” US Powerboating has a link to the RYA information. Sail World wrote an article soon after the RYA guidence was published, which paraphrased the RYA information.
  • Community Boating Inc. in Boston decribes methods used for maintaining engines on its safety boats, and the types of engine guards in use.
  • Gowrie Group seems to recommend a specific brand of guard that is pictured in its article.
  • A propeller design that originated in Australia is claimed to be safer because of its rolled-edge design. It is described here (see Products/Safer-propeller) and a video may be viewed here.
  • Testing and experience: Some organizations have tested propeller guards and have an opinion that outboard motorboat speed and maneuverability is reduced by the drag from the guard assembly, but other organizations have overcome that by increasing the horsepower of the outboard motor, or modfying the pitch of the propeller used with the guard.
    • 2012 article in Boat US describes methods of testing prop guards and sumarizes safe powerboat operation techniques.
    • Propeller Guard Test Procedure report was developed for the Coast Guard under the auspices of the American Boat and Yacht Council 1n 2013. This procedure is intended for use by developers of propeller guard devices and independent third party testing entities to test propeller guard products in a consistent, repeatable manner. An article about the procedure was published in a maritime industry publication.
    • A proponent of propeller safety writes regularly about prop guard benefits on his website.
    • Tests of a specific brand of prop guard were conducted in Port Washington NY and were published on the website of the prop guard supplier, with a version also published in WindCheck.